A spin-handle wrench is preferred to speed up the process of installing bolts and snugging them prior to tightening to final torque specifications. They do not require compressed air, and are much less likely to overtighten fasteners and/or strip out threads in the case.
Using a spin-handle wrench speeds up the rebuilding process dramatically. It also eliminates the possibility of stripping out any threaded holes in the case when using air impacts or air ratchets.
Several varieties of snap ring pliers will be needed, including some that will be modified for a particular purpose. On the TH350 and 4L60 transmissions specifically, the output shaft uses a small snap ring for retention, which is difficult to access. Pry it out carefully with a very small screwdriver, or use modified ring expanding pliers, which are easier.
A variety of snap ring pliers are required for transmission work. Some are available with removable ends to work with a wide variety of snap rings with the same tool.
Large ring expanders can be modified as shown. They are needed in the TH350 transmission to remove the snap ring on the front of the output shaft. They also work well when removing the spring cage retainers on the drums in both the TH350 and TH400 transmissions.
This is why you need a set of modified snap ring pliers. The output shaft front snap ring can be difficult to access and remove because it’s pretty far down in the case; it’s generally difficult to get both hands in there at the same time and see what you are doing.
An alternative to buying an entire assortment of snap ring pliers is to buy one set that has removable tips.
Pliers with removable tips are also available; one pair can cover a broad range of applications. Some snap ring pliers are also designed to be convertible, and can be modified in seconds to remove either inner or outer snap rings.
A variety of screwdrivers come in handy during the rebuild. Large flat-blade screwdrivers can be used to remove the snap rings in the transmission cases and also to reposition them. And, Phillips screwdrivers also double as alignment tools when putting the pump back on the case. A few minutes with a torch can quickly take a couple of small flat-blade screwdrivers and turn them into friction and steel removal tools.
By bending over the ends, they can be used to reach inside clutch drums or into the transmission case to pull steels and frictions out.
Large flat-blade screwdrivers are needed to remove the large snap rings from the cases on the TH350 and TH400 transmissions. You can also use them to remove the manual shaft seals from the case.
Phillips screwdrivers make great alignment tools for installing the oil pump and valve bodies on the case.
You can modify screwdrivers by heating 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.