Inspecting T86 And Transfer Case

Score on the bigger garage!

 

Hey @timgr (and @Stano316) - if we both have T86 cases with T90 guts, regarding small parts kit for seals and bearings etc. are those interchangeable as well since the cases are so similar? Which one did you get when you rebuilt yours and did you have any issues?

Specifically, what are the differences in application/fitment between this:
Crown Automotive T86AA Small Parts Kit for 66-67 Jeep CJ-5 & CJ-6 with T86 3 Speed Transmission
and this:
OMIX-ADA 18805.01 Small Parts Kit for 46-71 Jeep CJ, SJ & J Series with T90 3 Speed Transmission
Thanks!

 

I've never owned a Jeep with a T-86 or a T-90. I've rebuilt a few transmissions including Borg-Warner 3-speeds, and I bought any Jeep parts from dealer stock. I have recently bought parts for my T-18 from PartsMike. Both Novak and Herm would be good sources for transmission parts if you want advice along with your transmission parts. Supposedly Herm has measured and investigated the available parts to put together his own kits. Novak will likely sell you Crown stuff.

I would choose Crown over Omix, all day long. Specifically, I don't know what the differences are, if any. The T-90 gears look different from the T-86 gears, with the T-90 having straight-cut spur gears and straight splines on the main shaft. The front case pattern of the T-86 is larger than the T-90, and the same as the T-14 and T-15. The T-86 spur gears are beveled and the splines of the main shaft are helical. The small parts should be interchangeable, but I can't guarantee it.

If you have either kit, you can use the parts if they measure correctly. Buy an inexpensive micrometer and measure each part and compare it with what you are replacing.

 

I just purchased a T86 converted to a T90 from Herm and he supplies a whole new T90 shift stick top. So yes if you convert you need the T90 top and yokes. The T86 top that belonged to the case I sent him had a back up light hole drilled and threaded. The T 90 top he sent me didn't have the tapped hole. I asked him about it and he said the T90 top could be drilled and tapped. He didn't mention just switching out the rods and yokes so I'm not sure if can be done.

 

Question for the Experts - I have a T86AA with T90 guts. There is a pool of gear oil in the bottom of the spacer/adapter:


I would like to address this leak while I have the transmission and transfer case out of the Jeep.

Above is the parts diagram from the T86. K/W only has parts for the T90 (T90 Transmission).

What is the right move here to arrest this leak - 1) remove the adapter, 2) remove the bearing cap, and 3) replace the seal with a new felt seal from K/W?

 

Crown shows a small parts kit for a T-86 that appears to include seal #26 in your diagram above. This looks like (and I would expect it to be) a neoprene seal, which would seal the front bearing from the transmission oil. Maybe this does not work with the T-90 gears? A T-90 dripping from the front bearing retainer is a common problem. The factory oil retention methods on a T-90 (scroll? felt seal?) are a known issue, typically solved on a T-90 using a sealed front bearing.

If somebody has the number for that seal, I expect you can buy it by itself. If not, here's the parts kit: T86 Transmission | Crown Automotive Sales Co

RockAuto shows it:



There should also be a thin paper gasket between the bearing retainer #27 and the transmission case. Likely not available separately, but easy to make with gasket paper, or a thin coat of RTV or RightStuff should substitute fine.