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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Assumption: you mean “how to service / calibrate / repair” the Toyota H140F / H150F / H151F gearbox (not an engine carburetor). Below is a concise, ordered, theory-focused procedure and why each repair step cures specific gearbox faults. No extra chatter.

1) Define the symptom and basic theory
- What to note: noise (growl/grind/whine), inability to engage a gear, gear pop-out, slipping, hard shift, fluid leak.
- Theory: symptoms come from wrong input/output speeds, worn teeth/syncros, damaged bearings, poor lubrication, incorrect clearances (endplay/gear mesh), or linkage/selector misadjustment. Diagnose which subsystem (linkage, synchroniser, gears, bearings, seals) is causing the symptom.

2) Preliminary checks (non-invasive) — why first
- Check fluid level/type and condition (metallic particles, burnt smell). Theory: low/contaminated oil causes bearing/gear wear and poor synchroniser function.
- Verify external leak sources (seals, pan, breather). Theory: leaks cause oil loss and contamination ingress.
- Inspect shift linkage and selector mechanism for play, binding, worn bushings. Theory: misadjusted/loose linkage prevents true gear selection or causes partial engagement.
- Road/bench test to reproduce symptom. Theory: reproducing confirms which speed/operation causes fault and narrows down internals.

3) Linkage and hydraulic (if applicable) repair — when this fixes it
- Adjust/replace worn shift cables, bushings, selector shafts, detent springs. Theory: restoring correct geometry lets detent and shift forks fully move gears into engagement; fixes hard/shallow shifts and false “internal” faults.

4) Drain gearbox and inspect fluid contents
- Remove drain/inspection and note metal debris type (fine vs. chunks). Theory: fine filings = bearing/synchro wear; large bits = broken gear/one-way failure. This directs whether rebuild is required.

5) Remove gearbox — methodical disassembly
- Label and photograph positions. Remove bellhousing, input shaft, output shaft assemblies, synchros, bearings, shift forks, detents, end covers.
- Theory: internal inspection reveals wear patterns: pitting/peeling on synchro cones, scored gear teeth, play in shafts, axial play beyond spec.

6) Measure and inspect wear-critical components — why
- Check gear tooth faces for wear, pitting, broken teeth. Broken or heavily worn teeth -> replace gear or gear set. Theory: replacing restores tooth profile and gear meshing geometry so forces transmit at intended contact pattern, eliminating noise/catching.
- Inspect synchroniser rings (cone surface) for glazing, heat discoloration, or missing inserts. Theory: synchroniser friction surface must provide speed matching; replacing restores friction so shifts become smooth and gear engages without grinding.
- Check bearings (radial/roller/tapered), races for brinelling, play, heat marks. Theory: worn bearings allow shafts to misalign and change gear mesh/clearance causing noise and premature wear; replacing restores alignment and preload.
- Measure endplay/axial clearance and gear mesh/backlash with gauges. Theory: correct backlash ensures load is distributed across tooth face; too much backlash causes impact noise and gear clatter; too little causes binding and heat.

7) Replace wear parts and renew seals/gaskets
- Replace synchro kits, bearings, seals, gaskets, and any damaged gears/shafts. Theory: worn friction surfaces and bearings are the usual root causes; replacing these restores original friction coefficients, clearances, and oil sealing so the gearbox can function reliably.
- Renew seals and update breather if contaminated. Theory: prevents future oil loss/contamination.

8) Rebuild with correct shims, endplay and torque specs
- Set bearing preloads/shims and endfloat per factory spec; set gear mesh/backlash where adjustable. Theory: correct preload and backlash ensure shafts run concentric with designed spacing, eliminating axial play and restoring correct tooth contact pattern; this cures noise, vibration, and premature wear.
- Reassemble synchroniser hub/keys, detents, shift forks aligned to selector positions. Theory: correct reassembly ensures positive shift engagement and detent indexing.

9) Fill with correct lubricant, torque and bench-test
- Use correct grade and fill level. Torque bolts to spec. Bench shift through gears and check smoothness, detent feel. Theory: proper lubricant and assembly torque provide intended hydraulic film and clamping forces; bench testing verifies internal engagement before reinstallation.

10) Reinstall, adjust external linkage, road test, final check
- Adjust linkage freeplay and verify all mounts. Road test under load for all gears, listen/feel. Recheck drain plug for metal and fluid level after break-in. Theory: load testing validates repairs under operational conditions; rechecking ensures nothing was missed and parts are bedding in normally.

How each common repair fixes common faults (brief)
- Replaced synchroniser rings: fixes grinding/hard shifts by restoring friction surface for speed matching.
- Replaced bearings: cures whining/growling and excessive play by realigning shafts and removing play-induced vibration.
- Repaired/replaced gears: fixes broken engagement, clunking, and metal debris by restoring tooth geometry and load-carrying capacity.
- Linkage repair/adjustment: fixes false “internal” shift problems (won’t engage / partial engagement) by ensuring the selector physically moves the collar/spline into full engagement.
- Seal/gasket replacement plus correct fill: fixes leaks and prevents oil starvation-related wear.
- Correct shimming/preload/backlash: fixes noise, gear clatter, overheating, and premature wear by re-establishing correct gear contact pattern and shaft positions.

Failure modes to watch for after repair
- Continued metal in drain: indicates missed damaged part. Repeat inspection.
- Intermittent pop-out: likely selector shaft detent or fork wear—recheck fork alignment and thrust clearances.
- Overheating or rapid wear: check oil grade, fill level, and bearing preload.

End — theory-forward checklist (quick)
- Symptom -> isolate (linkage vs internal) -> fluid inspection -> disassemble -> measure wear -> replace friction/bearing/gears as required -> set endplay/backlash/shim -> reassemble with correct oil -> bench + road test -> monitor.

No questions.
rteeqp73

- **Safety Precautions**
- **Safety Glasses**: Protects your eyes from debris.
- **Gloves**: Protects your hands from grease and dirt.
- **Jack Stands**: Essential for safety when lifting the vehicle; never work under a vehicle supported only by a jack.

- **Tools Required**
- **Jack**: Used to lift the vehicle off the ground for access to the wheels. Ensure it's rated for the vehicle's weight.
- **Jack Stands**: Place under the vehicle once lifted to ensure stability during work.
- **Lug Wrench**: A cross-shaped or socket-type wrench that loosens and tightens the wheel nuts. Ensure it fits the wheel nut size.
- **Socket Set**: A set of sockets with a ratchet handle, typically 10mm to 17mm sizes for brake components (check your vehicle specifications).
- **Piston Tool or C-Clamp**: Used to compress the brake caliper piston to fit new brake pads. The C-clamp presses against the caliper and the back of the brake pad.
- **Brake Cleaner**: Cleans old brake dust and grease from components.
- **Torque Wrench**: Ensures wheel nuts and caliper bolts are tightened to the correct specifications.
- **Brake Pad Set**: New brake pads are required, as old ones wear out and may lead to decreased braking performance.

- **Replacement Parts**
- **Brake Pads**: Essential to replace if they are worn down (usually to less than 3mm thickness) or damaged. Worn pads reduce braking efficiency and can damage the rotors.
- **Brake Rotors**: Inspect for scoring or warping. If damaged, rotors may need to be resurfaced or replaced.

- **Procedure**
- **Lift the Vehicle**
- Use the jack to lift the vehicle at the designated jacking points.
- Securely place jack stands under the vehicle.

- **Remove Wheel**
- Use the lug wrench to loosen and remove the wheel nuts.
- Take off the wheel to expose the brake assembly.

- **Remove Brake Caliper**
- Use a socket from your set to remove the caliper bolts. Keep track of the bolts.
- Carefully slide the caliper off the rotor. Do not allow it to hang by the brake line; support it with a bungee cord or similar.

- **Remove Old Brake Pads**
- Slide out the old brake pads from the caliper bracket. Note the orientation for installation of new pads.

- **Compress Brake Caliper Piston**
- Use the piston tool or C-clamp to compress the caliper piston back into the caliper housing. This creates space for the new, thicker brake pads.

- **Install New Brake Pads**
- Place the new brake pads into the caliper bracket in the same position as the old ones.

- **Reattach Brake Caliper**
- Slide the caliper over the new pads and align it with the bracket. Insert and tighten the caliper bolts using a socket.

- **Reinstall Wheel**
- Place the wheel back on and hand-tighten the lug nuts.
- Lower the vehicle, then use the torque wrench to tighten the lug nuts to the manufacturer’s specifications.

- **Final Checks**
- Pump the brake pedal a few times to ensure the brake pads seat properly against the rotor.
- Check for any leaks or issues before driving.

- **Disposal**
- Properly dispose of old brake pads and any brake fluid according to local regulations.
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