How to Remove and Install a Transmission in a 1998 Chevy Truck

This is a step by step guide on how to remove and install a transmission in a 1998 Chevy truck

Steps

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    Park the truck in a place where you will be able to work on it efficiently. An ideal place is a roomy garage, but a concrete driveway, or at least a firm, smooth, level surface is needed to facilitate jacking the truck safely.
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    Remove the positive battery cable so any electrical short circuits will be avoided. Failing to do so could result in damage to the wiring harness.
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    Jack the truck up at the front end. You will need to lift the front wheels at least six inches above the floor so the transmission can be removed from underneath the vehicle when it is dropped down.
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    Remove the front drive shaft, if it is 4wd. Then remove the exhaust flange from the exhaust manifold. Remove the electrical and transmission oil cooler lines.
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    After you have removed all of these components, you need to drain the fluid from the transmission. After the fluid has drained out, you need to reinstall the fluid pan back on the transmission.
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    Remove the shifter linkage cable. Once removed, tie it up out of the way. Also, remove the speedometer cable and the vacuum hose from the shift modulator valve.
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    Remove the rear drive shaft. This should give you the room you need to remove the transfer case from the rear of the transmission, if the truck is four wheel drive. Remove the six bolts and remove it.
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    Remove the starter from the engine and remove the bolts attaching the transmission bell housing to the engine block. The front of the transmission will now be supported by the splined input shaft and mounts, so do not allow the rear of the transmission to drop in the following steps, or this could damage the shaft, seals, or torque converter assembly.
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    Use jack stands or a jack to support the rear of the transmission (and the front must not be allowed to drop, either). Remove the two bolts holding the transmission to the cross member, and the four bolts connecting the cross member to the truck's frame. Remove the cross member.
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    Remove the transmission, keeping it continuously supported, while sliding it toward the rear of the truck -- keeping the unit in line with the engine. You will need to slide it backward about 7 inches (17.8 cm) to clear the torque converter.
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    Lower the transmission to the floor, and slide it out from underneath the truck, keeping it as level as possible and in an upright position. You can now remove the bolts that attach the torque converter to the flywheel if it is to be removed for repair or replacement.
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    Install it in reverse order from the removal process.
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    Get the spline and input shaft to insert into the torque converter and pilot bearing. It's tricky. It has to be straight in line both ways with the insertion point, and preferably supported on its balance point (balanced from fore and aft, and side to side), securely strapped (for example) from falling, not dangling or flopping around. But, it must be angled the same as the car is (if the front of the car is raised for instance). It would be easier, if the entire car were lifted, level, not angled.
    • Gravity will fight your getting it in all the way in the spline-socket and into the bearing on the end, unless it is supported at its balance point and lined up perfectly.
    • Lifting the trans unsecured, or off balance, can cause chaos, wobbling, rolling, falling,...
    • The spline grooves must align both ways, vertically and horizontally.
    • The input shaft can hang-up on the pilot bearing edge, instead of proceeding in -- if the transmission is angled more than a few hairs -- if not balanced and aligned.
    • Do not allow the spline, alone to support the weight of the transmission.

Tips

  • Do this project on a concrete floor if possible, as a floor jack or such doesn't roll on soft surface. Strong, level, 3/4 inch (19mm) plywood may work over asphalt or gravel.
  • A breaker bar and a cheater pipe on the breaker bar handle are usually needed. Pneumatic (air) tools make the job faster and easier.
  • Using a transmission jack (one which lifts straight up), would make the process much easier, since the transmission is difficult to hold onto, or balance and very heavy.
    • A floor jack is a pain, as it must continually be rolled forward; then pushed and pulled to stay on point or in line. It keeps changing the location of the transmission as the lift-arm changes its angle (the lift and transmission goes backward as it lifts and forward as it lowers).

Warnings

  • The transmission is heavy, tilts and slides easily. Be careful lowering and raising it.
  • Do not work under a vehicle that isn't properly supported, a jack is not sufficient.
  • Transmission fluid is flammable and toxic, control and cleanup spills if they occur.

Article Info

Categories: Trucks