them up and bending the ends over. They have a variety of uses, including pulling steels and frictions out of clutch drums and cases.
A hook and pic set comes in handy for transmission rebuilding. They can be used to remove lip seals from apply pistons, steel check balls from the case, and to pull steel and friction plates out of the clutch drums. These sets are inexpensive and readily available at most auto parts and tool supply stores.
Use an awl to remove the retaining ring for the TH350’s accumulator piston cover. To fabricate one, all you have to do is grind the tip of an old screwdriver to a sharp tapered point with a bench grinder.
An awl with a sharp point also makes a great tool to remove the solid factory Teflon sealing rings on accumulators and servos.
A hook and pick set is handy for removing lip seals and lifting steel and friction plates from the clutch drums. An awl is handy for transmission rebuilding. It can be used to help line up bolt holes with gaskets and separator plates when installing the valve body, and also to remove the snap ring that retains the 1-2 accumulator in the TH350 case.
Transmission rebuilding involves precision and attention to detail; many items in the assembly must be measured for specification. A dial indicator is a nice addition to the arsenal for transmission builds. It can be used to check input or output shaft endplay before and after the unit is assembled. Because you may have selective shims available to set the shaft endplay, it’s nice to be able to measure it accurately. The other end of the dial indicator has a depth gauge, which is another handy tool. It tells you how far down in a drum a particular bushing was installed. You need to know this measurement before driving it out for replacement.
A dial indicator is used to determine input shaft endplay. You can measure endplay and then use shims or selective washers to keep it within specification.
Dial calipers are used to measure thickness or size and also depth. Good calipers are pretty much a mandatory item for transmission building, as you must measure the thickness of friction and steel plates when stacking clutch drums.
Use a dial caliper to measure the total thickness of one friction and one steel plate. You can then use this measurement when machining apply pistons to add more frictions to a clutch drum, or just to compare the dimensions of your replacement parts.
Some bushings are installed below flush for a reason. Before removing any bushing that is not flush, take a moment to measure the depth in the bore. Make sure to duplicate the depth when installing the new bushing. This eliminates the chance that any lube oil passages are blocked off and ensures that the bushing supports the correct corresponding part of the shaft or component.
Another measuring device is a micrometer. Use ball micrometers to measure round surfaces and quickly determine bushing thickness. Flat-tipped micrometers (for measuring diameter) can tell you the diameter of a valve in the valve body
A feeler gauge is used to measure the free travel of the clutches in the forward and direct drums. This ensures that the transmission functions correctly, that you have put the correct number of frictions and steels in each clutch pack, and that they are the correct thickness.
A standard caliper is a great tool to measure friction and steel plate thickness, as well as the total thickness of clutch packs. It can also be used to measure the bushings’ diameter (both outside and inside), as well as the thickness of apply pistons, steel plates, and frictions.
A standard 1-inch micrometer works equally as well for measuring frictions and steel plates, as well as the total thickness of a clutch pack.
You should also add a feeler gauge to your list. They are used to check clutch pack endplay in the forward and direct drums. A feeler gauge is also used to install the apply pistons in the forward, direct, and intermediate drums.
Several of the units covered in this book require a piston spring compressor inside the case. The TH350 and 4L60, specifically, use a low/reverse piston in the lower portion of the case. A snap ring holds the spring cage in; it must be compressed in place for removal.
You need a spring compressor to remove the snap ring inside the case on the TH350 transmission. You can fabricate one in minutes with a long threaded 3/8-inch bolt and a couple of pieces of flat bar.
You can use these to compress spring cages on other components, provided those pieces have a center hole. For drums without a center hole, the component must be held stationary and some sort of spring compressor used to push down on the spring cage to facilitate the removal of the snap ring.
You can use a shop press to compress the spring cages on the forward and direct drums with a piece of flat steel and a couple of sockets that are the same height. Pretty much anything that compresses the spring cage evenly and does not distort it will work here. Be extremely careful here, because a shop press has enough force to distort the spring cages and damage the drum if the cage hangs up on the snap ring groove for any reason.
A spring compressor is a required tool for transmission building. Shown here is a homemade unit fabricated from square stock and angle iron. A spring compressor allows the transmission builder to gently compress spring cages just enough to remove and install the retaining rings without damaging the spring cage.
A larger tabletop bench-mounted spring compressor is needed for building clutch drums. A shop press works equally as well, although this type of press tends to be much more difficult to set up and a lot slower to use.
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