T 90 transmission problems

[steve welder]

Happy to report my rebuilt engine runs great, my attempt tom rebuild my trans was not so great
After hearing some nasty sounding noises coming from my trans, I pulled it out and it was a mess
The trans was hard to shift into second and third, I assume I had some issues with the assemble of the synchroniser, I found it impossible to move by hand but what really hit me was the bent, bits and pieces of needle bearings from the countershaft cluster gears. They were everywhere and fine pieces of metal. The thrust washer was destroyed and if there was a spacer, I cant find it
The case is ruined, the area of the case, a boss area 3/4 of it was ground away. What could possible cause this? I assembled all those needle bearings carefully, used a dummy shaft and assemble grease
Luckily I have another case from a CJ3. I put a new 2nd gear, new bearings and synchros in this trans and I was hoping to reuse them
I have to find out the mistake im making

[bmorgil]

Take some pictures Steve. Why it failed to me is the most important part of a good mechanics job. I am wondering if we cant figure it out from Lots of pics. It is tough to tell from your description. You may have done everything correct. We don't know where all these parts are made anymore. Try it again Steve, if at first you don't succeed.....

[gmwillys]

I'm with Bmorgil. Don't let it get you down SW. Some forensic deconstruction should yield where the issue originated.

[steve welder]

Thanks, so disassembling trans I realised there was no rear thrust washer, from the damage it seems the needle bearings were forced against the other washer which is against the case destroying it and damaging the case
I had another case and this time got everything right and the cluster gear feels perfect.
I found that my dummy shaft for the cluster gear was to short and this was the reason I was having problems getting everything set up properly
I installed the main gear assembly, flipped the case over and thee cluster gear practically fell into place
My mistaken was letting the main shaft slip out the end of the case before I secured it and in had to start all over
Now every video ive watched shows the cluster gear on the bottom of the case to let you install the main shaft and gears
I was able to manipulate the synchro and leave the large gear off (first gear?) and install the main shaft into the input shaft and than install the first gear, the cover plate and shim
The trans spins free in all gears, i did notice pushing the synchroniser back and forth by hand was very hard and wanted to know if that was a issue I need to look into
I secured the main shaft so it doesnt move with two zip ties connected to a cover bolt
What do you think, im worried I screwed up again --------------Thanks for the help, its greatly appreciated

[bmorgil]

Steve, it looks like you have graduated to T90 trans technician! I always assemble them completely and run them through the gears a few times on the bench. The trans should shift with minimal effort with "The Stick" attached. The sychros can be difficult to engage with the cover off and a pry bar or fingers. It needs to shift however. If it spins freely and you can get it to engage all the gears and spin freely, put the cover and the stick on and run it through the gears. It should feel like a new transmission. It should not be difficult to shift if you are spinning it over and lining up the gears, with the shifter. Keep in mind the shifter has quite a bit of leverage over the sychro. It makes engaging the sychro much easier. This is also why you shouldn't drive with your hand on the stick. All that leverage will wear the shift forks down.

[steve welder]

Steve, it looks like you have graduated to T90 trans technician! I always assemble them completely and run them through the gears a few times on the bench. The trans should shift with minimal effort with "The Stick" attached. The sychros can be difficult to engage with the cover off and a pry bar or fingers. It needs to shift however. If it spins freely and you can get it to engage all the gears and spin freely, put the cover and the stick on and run it through the gears. It should feel like a new transmission. It should not be difficult to shift if you are spinning it over and lining up the gears, with the shifter. Keep in mind the shifter has quite a bit of leverage over the sychro. It makes engaging the sychro much easier. This is also why you shouldn't drive with your hand on the stick. All that leverage will wear the shift forks down.

Thank you, if you ever venture to the big apple I owe you lunch...... There is nothing like assembling the entire trans and finding the C clip for the main shaft which is exactly what I did LOL
Id like to fabricate something to hold that rear cover plate and rear bearing in place and than I could shift the gears without the mainshaft backing out. I learned it does not have to back out very far to screw up the syncros. Thanks again for the help

[bmorgil]

When your shifting it without the transfer case and drive gear on the main shaft, it will move around. You can take a metal strap and put it across two bolt holes and over the edge of the bearing to hold it firmly in the case.

Now lunch in the Big Apple... that sounds like a great time!

[steve welder]

When your shifting it without the transfer case and drive gear on the main shaft, it will move around. You can take a metal strap and put it across two bolt holes and over the edge of the bearing to hold it firmly in the case.

Now lunch in the Big Apple... that sounds like a great time!

Pretty much exactly what I just did. Trans shifts better than last rebuild so in it goes

[bmorgil]

It sounds like you have it now Steve. Watch that back man! I know you didn't want to crawl under there again.

[steve welder]

It sounds like you have it now Steve. Watch that back man! I know you didn't want to crawl under there again.

I finished it up today, cross member in, driveshafts hooked up, adjusted the clutch.....Started it up, (jeep is up on jack stands) ran it through gears and no noise and shifted good
Im a happy camper today.
I learned a few things along the way. When I pulled the trans, transfer case was off, I left the bell housing on, when I went to put the fork on I than realised why the bell housing comes off with the trans
I tried and tried to get that fork on through the clutch inspection cover, I dropped it into the bottom of the bell housing several times, using a magnet to retrieve it
Finally what I did was I tacked a 1/8 steel rod on the very end of the fork, just a slight tack and dont weld the steel rod all the way around.
Pushing the throw out bearing forward with one hand, I was able to maneuver the fork behind those tangs and unto the ball. Than twist the rod back and forth to break it off
I guess a little unorthodox but for me it was better than pulling everything apart