Manual Gearbox; 5-speed manual the design designation are H150F.
The apparatus ratios become: first 4.529:1, 2nd 2.464:1, third 1.49:1, 4th 1:1, 5th .881:1, reverse 4.313:1
Size, Spline OD & No. of Teeth 275 x 29.7 x 21

Handbook Gearbox; 5-speed manual the design designation is H151F.
The gear ratios were: first 4.081:1, 2nd 2.294:1, third 1.49:1, 4th 1:1, fifth .881:1, reverse 4.313:1
Size, Spline OD & No. of Teeth 300 x 32.4 x 14


The H151 uses a larger clutch. The H150 can be found in the 1HZ's.

A transmission was a machine in an electrical transmission system, which supplies controlled application associated with the energy. The term transmission relates in order to the gearbox that utilizes gears and equipment trains to provide rate and torque sales from a rotating power source to another unit.

In British English, the expression transmission is the entire drivetrain, including clutch, gearbox, prop shaft (for rear-wheel drive), differential, and final drive shafts. In American English, however, the term relates considerably particularly into gearbox alone, and step-by-step consumption varies.

The most frequent usage is in cars, where transmission adapts the production of internal-combustion motor into the drive tires. Such motors need to function at a comparatively high rotational speeds, which will be unacceptable for beginning, stopping, and slowly travel. The transmission reduces the bigger engine speeds towards slower wheel speeds, increasing torque in the act. Transmissions are also utilized on pedal bikes, set machines, and in which various rotational speeds and torques are adapted.

Frequently, a transmission has several equipment ratios (or simply just "gears") with the ability to switch among them as rate differs. This switching could be finished manually (by the operator) or immediately. Directional (forth and reverse) controls may also be offered. Single-ratio transmissions additionally exist, which merely replace the speed and torque (and sometimes way) of motor output.

In cars, the transmission generally try attached to the system crankshaft via a flywheel or clutch or fluid coupling, partially because internal-combustion engines cannot operate below a particular rate. The result of transmission is sent through the driveshaft to a single or maybe more differentials, which drives the wheels. While a differential may also incorporate gear reduction, their primary factor is let the rims at either end of an axle to turn at different speeds (essential in order to prevent wheel slippage on turns) since it adjustment the course of rotation.

Old-fashioned gear/belt transmissions are not the only procedure for speed/torque adaptation. Alternative mechanisms include torque converters and energy change (example. diesel-electric transmission and hydraulic drive system). Crossbreed configurations also exists. Automated transmissions use a valve system to shift gears using fluid pressures in conjunction with an ecm.

The necessity for a transmission in an automobile are due to the characteristics of the internal combustion motor. Machines usually run over a range of 600 to about 7000 rpm (though this varies, and is usually less for diesel machines), although the vehicles's rims turn between 0 rpm and around 1800 rpm.

Additionally, the motor produces its greatest torque and energy outputs unevenly across the rev range resulting in a torque band and a power band. Often the biggest torque is required once the automobile was going from rest or traveling slowly, while greatest power is required at high speed. Therefore, something is required that transforms the motor's production so that it can supply highest torque at lower speeds, and run at highway rates using engine nevertheless operating within their restrictions. Transmissions perform this transformation.
a drawing comparing the ability and torque groups of a "torquey" system versus a "peaky" one

The dynamics of a car or truck vary with speeds: at reasonable speeds, speed is restricted because of the inertia of vehicular gross size; while at cruising or maximum rates breeze resistance could be the prominent barrier.

Most transmissions and gears found in automotive and truck solutions tend to be contained in a cast-iron circumstances, though more frequently aluminium is used for lower fat especially in automobiles. You will find typically three shafts: a mainshaft, a countershaft, and an idler shaft.

The mainshaft stretches away from situation in both instructions: the input shaft to the motor, and the result shaft towards backside axle (on back wheel drive vehicles. Front wheel drives typically possess engine and transmission attached transversely, the differential becoming part of the transmission system.) The shaft was suspended because of the biggest bearings, and it is split to the input end. In the aim of the split, a pilot bearing holds the shafts collectively. The gears and clutches drive regarding mainshaft, the gears becoming absolve to turn in accordance with the mainshaft except when engaged by the clutches.

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1) Function — theory first
- In this H‑series gearbox the timing belt (or toothed drive belt) horizontally links rotating components so they keep precise angular phase. Typical roles: drive internal oil pump, drive countershaft/speedometer drive, synchronize shift mechanism or link input and intermediate shafts where gears are belt‑driven. Because it is toothed, it prevents slip and enforces exact positional relationship between driven parts.
- A worn, stretched, cracked or failed belt loses tooth engagement or tension → lost phase, slipping, noise, abrupt loss of drive or loss of lubrication flow (if it drives an oil pump). The repair restores correct angular relationship, corrects tension, and eliminates degraded bearings/idlers that cause misalignment and accelerated wear.

2) Symptoms that indicate belt replacement is needed (why you repair)
- Ticking/knocking/whine from the gearbox housing consistent with belt tooth wear.
- Intermittent loss of drive, sudden disengagements, or incorrect speedometer reading.
- Oil contamination with belt fragments or visible glazing/cracks at inspection.
- Excessive belt slack, or seized/rough idler/tensioner bearings.
Repair fixes these by replacing the fatigued element that enforces phase and replacing worn support bearings so the belt runs on true, correctly‑tensioned pulleys.

3) Preparatory theory and safety (before you touch bolts)
- The belt must be replaced with the gearbox in the same reference position used for alignment marks — otherwise phasing is lost and gears will not mesh or pumps will be out of phase.
- New belt tension is critical: too loose = skip and tooth wear; too tight = excessive load on bearings and shafts. Tension is set to a specified static or measured deflection and verified by rotating the assembly to even seating.
- Replace idlers/tensioner and seals/gasket that are accessible when the cover is off. A new belt on worn idlers will fail prematurely.
- Always drain oil if cover removal exposes oil passages, and prevent contamination by cleaning mating faces before reassembly.

4) Step‑by‑step procedure (ordered, with the why beside each step)
1. Prepare: park on level ground, secure vehicle, disconnect battery if required for safety. Raise and support vehicle if necessary for access. Gather new belt, tensioner/idlers, gasket, sealant, oil, and proper tools.
- Why: safe access and parts ready avoids rushed reassembly that causes misalignment.

2. Drain gearbox oil if the cover or housing you’ll open is oil‑retaining.
- Why: prevents oil loss into work area and avoids contamination of mating surfaces.

3. Remove external components blocking access: covers, linkages, brackets, ancillary drives.
- Why: required to expose timing cover and pulley set while preserving their correct positions.

4. Remove timing/outer cover(s) to expose the belt and pulleys. Clean outside to prevent dirt ingress.
- Why: cleanliness prevents contaminant damage to new belt and bearings.

5. Note and photograph alignment marks on all pulleys/shafts and gearbox housing. If no clear marks, rotate to manufacturer’s “timing/neutral” marks positions.
- Why: ensures you can re‑establish the exact phase relationship. This is the most important theoretical step — phase equals function.

6. Loosen and/or release the tensioner per design (spring or hydraulic). Do not immediately remove belt until you’ve recorded marks and tensioner position.
- Why: controlled release avoids sudden movement of shafts that can change alignment.

7. Remove the belt. Inspect belt teeth, cord, and both sides for cracking, oil contamination, hardening. Inspect idler and tensioner bearings by spinning them — any roughness or play = replace.
- Why: confirms root cause and determines what to replace beyond the belt. Bearings and pulleys control runout and contribute to failure.

8. Inspect all pulleys, shafts, seals and housing for wear, scoring or misalignment. Replace any worn pulley or shaft component. Replace cover gasket and any oil seals that would be exposed during reassembly.
- Why: a new belt running on a damaged pulley or leaking seal will fail quickly or contaminate the belt.

9. Fit new tensioner and idler bearings if recommended. Lubricate per spec if required.
- Why: new bearings have correct preload and low friction; this prevents noise and uneven belt loading.

10. Install the new belt, preserving the pre‑marked positions on pulleys and housing so the installed belt has the same phase. Route the belt to match original tooth engagement.
- Why: the belt must re‑create the exact angular relationship that was recorded — that is how the gearbox functions correctly.

11. Set initial tension per manufacturer specification (measured deflection or tension gauge). If a spring tensioner, set to the specified indicator position. If adjustable, tighten to spec and lock.
- Why: correct tension prevents tooth skip (too loose) and bearing/shaft overload (too tight). It also ensures consistent running-in.

12. Slowly rotate the input shaft (or turn the gearbox by normal rotation method) through several full revolutions (at least 5) by hand while observing timing marks and listening/feeling for binding or irregularities.
- Why: this seats the belt, distributes loads, reveals mis‑phasing, and ensures no interference.

13. Recheck timing marks and final belt tension after rotation; adjust if necessary and torque locknuts to spec.
- Why: belts can settle; final adjustment ensures long life and correct phase.

14. Reinstall covers, gaskets and any removed linkages. Refill gearbox oil to the correct type and level.
- Why: seals and oil are part of the system that preserves belt life and lubrication of bearings.

15. Bench/idle test then road test: listen for abnormal noises, monitor operation, recheck for leaks and re‑inspect tension after short run (some designs recommend re‑tension after a set mileage).
- Why: in‑service verification confirms the repair actually fixed the symptom and that components ran correctly under load.

5) How the repair fixes the fault — concise
- Replacing the belt removes the mechanically degraded element that lost tooth engagement or tension. Replacing worn idlers/tensioner restores the correct support geometry and reduces runout and eccentric loading.
- Correct installation (marks aligned) restores the precise phase relationships that allow gears, pumps or speedometer drives to operate as intended. Correct tension prevents slipping and stress peaks.
- Verifying rotation and re‑tensioning ensures the belt seats evenly and that no hidden interference or improper phasing remains. This eliminates the root causes (wear, misalignment, bearing failure, contamination) rather than treating symptoms.

6) Important cautions (practical theory)
- Never reuse a belt that shows any fatigue, glazing, or oil contamination — the tensile core degrades before visible failure.
- Always replace tensioner/idlers if there is any doubt — they are the usual second‑order failure cause.
- Torque to manufacturer specs and use the correct belt type/width and tooth profile; mismatched belt geometry changes load distribution and causes rapid failure.
- If the belt drives a lubrication pump, failure can cause catastrophic bearing damage—do not test-run long without confirming oil pressure/flow.

End.
rteeqp73

- Safety first
- Wear safety glasses, gloves, and sturdy clothes to protect from fluids, dirt and sharp edges.
- Work on a flat surface, use wheel chocks, and support the vehicle securely with jack stands if you must get under it. Never rely on a jack alone.
- Disconnect the negative battery terminal before touching electrical connectors to avoid short circuits.

- Quick note about parts and fitment
- Confirm the exact gearbox model and serial/part numbers before buying parts; Toyota/H-series transmissions can have variations. Use VIN or the gearbox stamped code to order the correct blower motor assembly or components.
- Common replacement items during blower motor service: blower motor assembly (fan+motor), mounting screws/bolts, electrical connector/pigtail if corroded, any small O‑rings or dust seals around the motor, and sometimes a short length of heat‑shrink or wire for repair. Replace what is worn or damaged.

- Tools you will need (detailed descriptions and how to use them)
- Socket set with ratchet and extensions (metric sizes likely): sockets fit over bolt heads; use the correct size to avoid rounding. Extensions let you reach recessed bolts. Use the ratchet handle to turn sockets; pull/push to tighten/loosen, avoid cheater bars on small ratchets.
- Combination wrench set (metric): open-end and box-end wrenches for bolts in tight spots where a socket won’t fit. Use box end for best grip; open end for quick turning where clearance allows.
- Torque wrench (click‑type, metric Nm range): set to the specified torque and tighten until it clicks to avoid over/under tightening critical bolts (mounting bolts often require a specified torque). If you don’t have one, you can snug bolts but get a torque wrench for final tightening.
- Screwdrivers (Phillips and flathead): for prying plastic clips or removing screws. Use correct blade size to avoid cam‑out.
- Needle‑nose pliers and standard pliers: for pulling clips, holding small parts, bending and repositioning connectors. Needle‑nose is useful for working in tight areas.
- Multimeter (DC volts / continuity): to check power and ground at the blower motor connector and test motor continuity. Set to DC volts to confirm battery voltage at connector; set to resistance/continuity to check motor windings.
- Wire brush and contact cleaner: to clean corroded connectors and mating electrical surfaces. Spray cleaner, brush gently, then dry before reconnecting.
- Penetrating oil (e.g., PB Blaster): to loosen rusted or seized bolts. Apply and let soak per instructions.
- Small pry bar or plastic trim tools: to remove clips and gently pry housings without damage. Plastic trim tools avoid scratching plastic housings.
- Shop rags and drain pan: to catch any small fluid drips or dirt, and to keep the work area clean.
- Work light or headlamp: to see in dark locations around the gearbox.
- Safety jack stands and hydraulic jack (if required): a hydraulic jack raises the vehicle; jack stands hold it safely. Required if blower motor is accessed from underside.
- Replacement parts and consumables: replacement blower motor assembly (OEM or equivalent), replacement bolts if original fasteners are corroded, small O‑rings or sealing washers if present, dielectric grease for electrical connectors.
- Optional but strongly recommended: service manual or repair sheet for your exact gearbox model (contains torque specs, disassembly order and diagrams). Without it you risk incorrect reassembly.

- How to use the key tools (beginner tips)
- Ratchet and sockets: pick the socket that fits flush on the bolt. Place socket fully over the bolt head, use an extension if needed. Turn counterclockwise to loosen, clockwise to tighten. If stuck, apply penetrating oil, wait, then try again. Use steady force—don’t jerk.
- Torque wrench: set the desired torque by rotating the handle to the readout, then tighten until you hear/feel the click. Practice on a spare bolt to get used to the feel.
- Multimeter: set DC volts to 20V range to check battery voltage. Probe positive and negative terminals on the connector with probes; about 12V with ignition on (or as specified) means power is present. For continuity/resistance, remove the motor connector and measure across motor terminals; very high or infinite resistance indicates an open winding.
- Needle‑nose pliers: grip small clips or wires near their base to pull; don’t pull by the wire insulation only—use the connector body.
- Penetrating oil: spray on the bolt threads and allow 5–15 minutes to soak. Wipe off excess before loosening.

- Step‑by‑step removal and replacement (generalized for beginner; follow with caution)
- Prepare workspace: chock wheels, lift and support vehicle on jack stands if blower access is from underneath, or if working from engine bay make sure engine is cool and gearbox area is accessible.
- Disconnect battery negative terminal to prevent shorts.
- Locate the blower motor on the gearbox housing. (Exact location varies by model — refer to the service manual or visually trace the fan housing/connector.)
- Inspect mounting area for dirt, wiring, and connectors. Clean loose dirt so debris won’t fall into open ports.
- Unplug electrical connector from the blower motor. If stuck, depress the locking tab and pull the connector; use a small flathead to lift the tab gently if needed.
- Remove any retainers, clips or shielding that obstruct access to the blower motor mounting bolts. Use screwdrivers or trim tools as appropriate.
- Spray penetrating oil on mounting bolts if they look rusted; let soak.
- Use the correct socket/wrench to remove mounting bolts. Keep bolts in order and note orientation of any washers or spacers.
- Carefully withdraw the blower motor assembly. Be mindful of any small gaskets or seals — save them if reusable or plan to replace them.
- Inspect the removed motor:
- Check for free rotation of the fan shaft by spinning it by hand. Seized or noisy bearings mean motor should be replaced.
- Smell for burned odor or look for melted plastics or excessive corrosion.
- Use multimeter to check motor windings for continuity and check voltage at the connector while key is on to confirm power supply.
- Decide if replacement is required:
- Replace the motor if it’s seized, noisy, has burned windings, has no continuity, or if power is present at the connector but motor doesn’t run.
- Replace wiring/connector if corroded, broken, or intermittent. Replace mounting bolts or seals if damaged.
- Install new or refurbished blower motor:
- Compare new part to old to ensure match (mounting holes, connector type, rotation direction).
- Fit any new O‑ring or seal, seat motor in its housing, align bolt holes.
- Reinstall bolts finger‑tight, then torque to manufacturer spec (use service manual). If you lack the spec, tighten evenly and snugly, then get exact torque later — do not overtighten.
- Reconnect electrical connector, applying a small amount of dielectric grease to contacts if desired.
- Reinstall any shields or clips removed earlier.
- Reconnect the battery and test operation:
- With the vehicle safely in park/neutral and parking brake set, operate the blower (or start engine if required) and verify normal operation across speeds if applicable.
- Listen for unusual noise and check for leaks or loose mounting.
- Lower vehicle if lifted and perform a final check.

- Typical reasons to replace the blower motor and what to buy
- Burned or open windings (motor dead) — replacement blower motor assembly required.
- Worn brushes or bearings (noisy, slow, or intermittent) — often best to replace the whole motor assembly rather than attempt brush replacement unless rebuild parts are available.
- Corroded or damaged electrical connector — replace connector/pigtail for reliable contact.
- Seals/gaskets damaged during removal — replace to maintain sealing and prevent contamination.
- Buy OEM part if possible (same part number stamped on removed motor or matched by VIN). If OEM is unavailable, buy a high‑quality aftermarket unit with identical mounting, connector and electrical specs.

- Troubleshooting quick checks (use multimeter)
- No power at connector with ignition on: trace wiring back for a blown fuse, relay or switch. Check related fuses and relays in the fuse box.
- Power present but motor does not run: motor likely failed; replace.
- Motor runs but slow/noisy: bearings or brushes failing — replace motor.

- Additional notes and cautions
- Exact bolt locations, torque specs and removal order vary by gearbox variant — consult a factory service manual or a reliable repair guide for your H140F/H150F/H151F model for precision.
- If you find damaged internal gearbox components (metal shavings, heavy contamination) while accessing the blower area, stop and consult a professional — internal gearbox issues may be complex and unsafe to continue alone.
- If you are unsure at any step, a local independent mechanic can confirm diagnosis and fitment.

- Summary of commonly required replacement parts
- Blower motor assembly (OEM or matched aftermarket)
- Electrical connector/pigtail (if corroded)
- Mounting bolts or washers (if corroded or stripped)
- Small seals/O‑rings or dust shrouds (if present and damaged)
- Fuse/relay (only if diagnostics show they are faulty)

- Final reminder
- Get the correct part by confirming gearbox code and part numbers; use a repair manual for torque values and diagrams. Follow safety practices and use the recommended tools (particularly a torque wrench and jack stands) for a safe, durable repair.
rteeqp73

1) Theory — what the TPS on these gearboxes does
- The gearbox TPS (often implemented as either a 3‑wire potentiometer or a 2‑wire throttle/kickdown switch mounted to the transmission or throttle/kickdown mechanism) tells the transmission ECU/hydraulic controller how far the throttle is open.
- The controller uses that signal to set shift points, line pressure (shift firmness), kick‑down downshift, and torque‑converter lockup.
- A 3‑wire TPS is a variable voltage divider: it has a 5 V reference, ground, and a wiper that produces a smooth voltage proportional to throttle angle (typically ~0.5–4.5 V range on most systems).
- A 2‑wire switch simply closes at a certain throttle position to request kickdown or high line pressure.
- Faults (wear, corrosion, broken wires, bad reference, mechanical misalignment) cause incorrect or no signal → incorrect shift scheduling (early/late shifts), harsh or soft shifts, no kickdown, limp mode or fault codes.

2) Tools and equipment
- Multimeter (DC volts, continuity, and ideally an oscilloscope or scan tool with live TPS data)
- Basic hand tools (screwdrivers, sockets, small torque wrench)
- Contact cleaner, small brush, dielectric grease
- Replacement TPS (OEM or correct spec) or replacement switch/cable parts
- Safety gear (gloves, eye protection)

3) Safety and preliminaries (do these first, in order)
- Park on level ground, block wheels, and apply parking brake.
- If working under vehicle, use jack stands; do not rely on a jack.
- Disconnect negative battery terminal when removing electrical connectors or sensor to avoid shorting. For live signal testing you will reconnect battery as needed but be careful.

4) Locate and inspect (visual + mechanical)
- Locate the TPS/kickdown switch on the gearbox/throttle linkage (follow wiring harness to sensor).
- Visually inspect: wiring harness, connector pins, corrosion, fractured insulation, bent actuator, cable routing and stops.
- Check mechanical movement: move throttle linkage smoothly through range and watch sensor actuation — it should move smoothly without play or slop.

5) Electrical theory and diagnostic order (how to test)
A. Identify type: count connector pins. 3 pins → potentiometer; 2 pins → switch.
B. Potentiometer (3‑wire) tests in order:
- Backprobe connector with ignition ON (engine off) or use scan tool for live data.
- Measure reference pin ≈ 5 V (ignition ON). If no 5 V, suspect ECU power/reference issue.
- Measure ground pin ≈ 0 V. If not, check chassis ground.
- Measure wiper voltage at closed throttle and at wide open throttle (manually move linkage). Voltage should move smoothly and monotonically from low to high (e.g., ~0.5 V → ~4.5 V). No sudden steps or dropouts.
- Wiggle wires and move linkage while watching voltage for intermittent breaks.
- Resistance test (engine off): between end terminals should be steady (a few kΩ typical), and wiper resistance should vary smoothly.
C. Two‑wire switch tests:
- With multimeter on continuity, operate throttle through range: switch should change state (open/closed) at expected position.
- Wiggle wires to find intermittent contact.
D. If available, use a scan tool to observe TPS live data vs pedal position and compare to expected profile (smooth curve).

6) Interpretation of test results (what each fault means)
- No 5 V reference → ECU or wiring power problem (not sensor).
- Wiper voltage stuck or jumping → internal wear/dirty track or broken wiper (replace sensor).
- Intermittent continuity/voltage with wiggle → wiring or connector fault (repair wiring or connector).
- Mechanical play or wrong angle → misadjusted cable/stop or worn linkage (adjust/replace mechanical parts).
- Corroded connector pins → high resistance causing wrong readings (clean or replace connector).

7) Repair procedure (order of actions)
- A. Minor fixes first (in order): clean connector pins with contact cleaner; apply dielectric grease; secure loose wiring; route/clip cable away from heat/sharp edges. Re-test.
- B. Adjust linkage/cable: if sensor is adjustable, set the sensor to the nominal rest position specified by OEM (if you don’t have spec, set it so wiper voltage is at low end at closed throttle and rises smoothly to high end at full throttle). For a kickdown cable adjust freeplay and travel per manufacturer method (ensure full travel engages switch). Re-test.
- C. Replace sensor if tests show bad voltage curve, dead wiper, or internal intermittent faults:
1. Disconnect battery negative.
2. Unplug sensor connector. Note orientation and any alignment marks.
3. Remove mounting screws/bolts and extract sensor—retain any shims/positioning parts.
4. Fit new sensor in same orientation; if shims were present, restore them. Tighten bolts to snug/torque spec if available.
5. Reconnect connector, reconnect battery, and re-test voltage/continuity per above.
- D. If wiring damaged, cut back to good wire, use correct crimp connectors, heatshrink, and secure harness. Re-test.

8) Calibration / relearn and verification
- Some ECUs require no formal programming; others will adapt automatically after a drive cycle. Use a scan tool to clear stored codes, then monitor live TPS values while slowly opening throttle to ensure smooth change.
- Road test: verify normal shift behavior, correct kickdown response, no limp mode, no transmission‑related codes. If shifts are still wrong, re-check signal with scan tool while driving under load.

9) How each repair action fixes the fault (theory applied)
- Cleaning connectors reduces contact resistance and restores a clean 5 V reference and ground return path, removing voltage drops that falsify throttle position.
- Repairing wiring restores continuity and eliminates intermittent open/shorts that cause spurious signals or dropouts, which the controller can interpret as sudden throttle changes → bad shifts.
- Adjusting cable or sensor angle ensures the sensor/wiper maps the actual throttle travel correctly to the controller’s expected voltage range; correct mapping returns shift timing and pressure to design values.
- Replacing a worn/dirty potentiometer replaces the electrical element that produces a smooth analog voltage. A bad pot produces jumps, dead zones or false readings; replacing it gives the controller accurate, stable input so it can choose correct shift points and lock‑up behavior.
- Clearing codes/relearning forces the controller to stop using cached faulty adaptation and use the restored correct signal for shift logic.

10) Typical symptoms and expected result after repair
- Symptoms before repair: erratic or harsh shifts, failure to downshift/kickdown, stuck in limp mode, transmission slip or chatter, transmission fault codes.
- Expected after proper repair: smooth monotonic TPS voltage, correct shifting under load and throttle, restored kickdown, fault codes cleared and not returning.

Done.
rteeqp73