66 Cj5 Won't Go Into Third

Full disclosure: I intend to buy this rig, but I have not yet, so I cannot go look/try anything. I am really trying to figure out whether, when I take delivery, I should have it towed to a transmission shop or home. I am a Jeep noob, but experienced with cars and trucks.

Supposedly rebuilt transmission (original - t90?). New sychros. Goes into reverse, first and second fine. Just not third. Thoughts? Bent shift fork? Whatever guesses you have, please include difficulty and time to fix for an average home mechanic and whether the transmission has to come out.

Thanks!

B.

 

I have seen some of the aftermarket blocker rings that were not machined correctly, the notches for the keys must be perfectly centered on the teeth and the correct width. If they are off it will not shift into gear or it will grind depending which way they are off.

 

Your worst case is replacement of the transmission. These transmissions can be sourced from Herm T-90 Transmissions | Herm The Overdrive Guy among other places. Parts for the T-90 are widely available on the aftermarket.

Just about anything you'd do to a manual transmission requires the transmission to come out. Removal and replacement is easy in a Jeep, and the T-90 is easy to work on.

 

wrong input shaft?

 

Make an offer that allows you the cost of a trans rebuild.

 

yep and if you have been working on cars . a jeep is just another on going project

 

I just did my t-90 rebuild . there are plenty of videos to check out . Take a look at them and see if you want to mess with it .

 

About the only things you can do to a T-90 in the car is change the oil and look at the shift top. Not much happening in the shift top - there's a pill between the rails that locks out the opposite rail to prevent two gear at once. 2 & 3 are on the same fork, and 1 & R on the other, which is a sliding gear - primitive. You could take the floor panel off, remove the shift top off and take a look. You must make sure that each fork goes back into its groove on the synchro hub (2-3) and sliding gear (1-R).

Possible the owner put the synchro hub together wrong or left out a snap ring or something.

"New synchros" probably means new blocking rings - I would not call that "rebuilt." Crown Automotive T90 Blocking Ring J0640397

Again, Jeeps are easy to work on. The components are comparatively small, there's a lot of room under the car and around the engine, and the technology is quite basic. Near 100% that the transmission has to come out.