T86aa Synchronizers

So in my 1966 cj5 my t866 has been having some issues. Ive narrowed it down to the synchros being the issue, and I want to get all the info I can on them before I buy new ones. I found a synchro unit for sale a few days ago but i couldnt find them today. How many synchros are there in this tranny? Just first gear or? Would the 100 dollar synchro unit be all i need and if so does anyone know a good place to buy new ones?

 

Only 2-3. I might have a new old stock one but you might want to narrow down what your problem is first. What exactly makes you think it needs the synchro?

 

You mean the blocking rings? There is a synchromesh hub that slides into the blocking ring. One hub, two blocking rings.

Yes, describe your symptoms. A T-86 is an "advanced" T-90, and it may be cheaper to put all new T-90 gears in the T-86 case, rather than find parts for a T-86.

 

Everytime I shift the gears will grind, as well as it poping out of third every time I let off the gas. Also when I dropped my tranny a year ago I saw that the gold colored ring (which I later realized is part of the synchro unit) looked like its teeth were worn. At time time I didnt really even think anything of it.

 

The gold-colored ring is the blocking ring, sometimes called a synchro ring. They are a wear item, and when worn the gears will clash when shifting, but they should not affect staying in gear. I expect you are going to have to take the transmission apart and inspect for worn parts, more than just the blocking rings.

Herm sells a rebuilt "modified" T-86 that is a T-86 case with T-90 gears. If you have a lot of parts to replace, that may be a practical choice. Or you can find a T-90 core transmission and rebuild your T-86 with T-90 gears... there are plenty of new parts for the T-90, not so many for the T-86. T-86 Transmissions | Herm The Overdrive Guy

There's lots of information about rebuilding the T-90 online, like here The Novak Guide to Rebuilding the Jeep T90 Transmission
The process for a T-86 is the same, except none of the gears are interchangeable.

 

Willys America Transmission Synchro Unit for Willys Overland T86-AA & T90A-1 Transmissions for anyone else who is looking for replacement parts at a better price this is where i got my syncros unit $65. They apparently raise it to$85 the very next day though!

 

Unless I could see it, I would worry that part is wrong for the T-86. The T-90 has straight splines on the main shaft, and the T-86 splines spiral.

This is a T-86



Notice the spiral in the main shaft splines, and the bevel of the sliding gear teeth. Both are straight in a T-90.

<edit> I dashed this off on my way out the door at work... thinking about it a little more, the synchro hub may exchange between the T-90 and T-86. Everything I've heard/read says you have to use everything from a T-90 or everything from a T-86, except the case and top. If the hub works for either transmission, you can get T-90 parts from oodles of places. If I needed a hub, I'd call Herm and 1) ask if the T-90 hub will work and 2) get the part from him.

 

I have a complete. now spare, COMPLETELY DISSASSEMBLED T 86 IN THE GARAGE, Is it you?