I have been rebuilding my 69 Buick Skylark for a long time now, and the final issue is the TH400 transmission. First it was the vent tube being clogged, causing a backflow up the dipstick at shut down; then the seal around the dip tube, causing a small leak at shutdown; then the modulator was stuck, a new unit was installed; then the parking pawl spring needed to be slightly stretched to adjust the pawl latch to engage the drum, then the torque converter was replaced, in a desperate effort to get the transmission to stop from spinning in all gears. Despite getting all those other corrections completed, I still could not get the transmission to stop from spinning, From different resources, I concluded it was the front gear clutch not disengaging, and ensued to try and air test it. So after removing the transmission for the 3rd time, I tried to air test it using the front pump housing, and I could not hear or view any changes, and decided to disassemble the front clutch drum to check and see if there was anything stuck or jambed. After a thorough inspection of the springs and interior of the drum clutch, nothing was found in the assembly, all seemed clean and movement free. It was then discovered that I needed two different clutch piston seal protector tools to re-assemble the forward clutch drum. These tools are both from Kent - Moore, J21362-1 for the inner clutch piston seal and J-21409 for the outer clutch piston seal. The only problem is that the outer seal protector COST. Tillman Tools wants $881, Freedom Racing needs $539, even Ebay lists it for $299 and $300. For these prices, I am half way to having someone else simply rebuild it for me. Pardon my lack of understanding, but the inner seal protector tool is barely a plastic dixie cup, how can the outer tool cost $300, at best. Does anybody have any tricks for assembling this clutch without this outer clutch seal protector, or possibly have one they could part with for less than $300? Maybe a rental deal? Something? Anybody know of a reliable rebuilder in the Jersey area? Hell, the tranny is already out and sitting on my bench. Open to all suggestions here. Thanks for any help you can offer
I bought a set of 3 tools years ago for under 50 off ebay. All 3 are plastic. You can a .015-.020 feeler gauge and slide it round and round to fold the seal down......just don't push hard on the piston. And work both the inner and outer seals, and don't work the feeler gauge like a saw or you can cut the lip seal.
Lip seal tool ... I have used thin rigid plastic strips with success. T-400 can be assembled / disassembled with basic tools in the shop (mostly). I made a few for compressing springs and such. If you need a shop - take it to Meenan Transmissions in Lansdale, PA. Family owned and operated since 1967
I use the "wire" loop tool. (link below) Center seal goes in "Lip" facing you (up),with the drum, sprag side (hub), on the bench. Then put the inner and outer seals on the piston, and with everything lubed up, start working around the center seal, then the outer seal, and back to the center seal. Do not "push" the piston while working the tool, but just enough pressure to keep it going into the drum, and go all the way around both seals. Sometimes you have to go back and forth on them a few times before it drops in. Use enough lube that the seals are not "dry" and you (should) feel the piston "pop" in I use Assemblee Goo green. Make sure you don't get the seals from the kit mixed up. Center support is a tiny bit larger, but it won't seal. https://www.ebay.com/itm/2953197984...837436483&abcId=9317284&merchantid=5072316736
I've not done a th400 but used a ring I cut out of a two liter plastic bottle like this ring above to help get lip seals on the trans stuff I have done. Also used a feeler gauge blade as suggested above. Careful install, goo lube used, and an air check to make sure it works. And additional air checks as you assemble can save a bunch of pulling it back out for stuff that could be caught with an air check.
I always used the drawer removal tool that came with my Snap-On tool box. (Photo was hi-jacked from the internet)
