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T-90 shift tower issues

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CJ2a6527 View Drop Down
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    Posted: 17 Oct. 2021 at 8:08pm
OK Guys, I seem to have a bit of a problem. Although it is somewhat self inflicted just bear with me and pay attention..LOL.
When I got my Jeep it had been popping out of second for a while.
I ordered a replacement OMIX-ADA complete tower and installed it. The Jeep shifted great. Never popped out of gear or had any of the old problems. BUT!!!
The shifter is completely different than the original. I hated the way it looked. It is much thicker and straighter than the original.
So I took apart the new shifter planning to install all of the new parts on the old shift tower.
Only AFTER disassembling the new shifter did I realize that the new shift tower parts won't even fit in the old shifter.
The shift rails are completely different than the originals and the shift forks won't fit the old rails.
Soo, I used the new poppet balls and springs and replaced the factory pins with roll pins. The original shift forks are much tighter on the rails than they were to begin with and the poppet springs and balls are much better (one spring was broken).
But now the dang thing pops out of second again.
I can order new shift forks but who knows if they will even fit the old rails?
Any ideas?

THE TRANSMISSION IS FINE!!!! It was rebuilt several years ago but the shift tower was not touched.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DMusil Quote  Post ReplyReply Direct Link To This Post Posted: 17 Oct. 2021 at 8:38pm
Most likely second gear is worn and or main shaft end play is excessive.  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote CJ2a6527 Quote  Post ReplyReply Direct Link To This Post Posted: 17 Oct. 2021 at 8:40pm
Why would you say that when I wrote in my post that the transmission is good? 
 I know for a fact that the transmission doesn't have 500 miles on it after the rebuild. The shift tower was not rebuilt and it continued to pop out of second but my uncle didn't care and I do.
 

Edited by CJ2a6527 - 17 Oct. 2021 at 8:44pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 17 Oct. 2021 at 9:10pm
As far as we the readers can determine the problem may lie in either the shift tower assembly or the second gear or in both.

The best way to rule out second speed gear is via visual inspection.
Take a very close look at the engage cogs on the front of the second speed gear. 
The cogs need be sharp and crisp without rounding at the points.
That is most commonly the problem found with the second speed gear.

Let’s say then that the second speed gear is acceptable.
In that case one should put the shift tower into position and shift the T90 into second gear. 
Next carefully remove the shift tower by lifting it straight up.
Notice exactly how far synchronizer sleeve is engaged onto the second gear engage cogs. 
If not fully engaged then the problem certainly lies with the shift tower assembly.

There are basically 2 other issues that may also effect gear. engagement.
Condition of the synchronizer plates and excess end play of the main shaft.


Edited by oldtime - 17 Oct. 2021 at 9:18pm
Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963)
Zero aftermarket parts

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Post Options Post Options   Thanks (0) Thanks(0)   Quote CJ2a6527 Quote  Post ReplyReply Direct Link To This Post Posted: 18 Oct. 2021 at 6:58am
Originally posted by oldtime oldtime wrote:

As far as we the readers can determine the problem may lie in either the shift tower assembly or the second gear or in both.

The best way to rule out second speed gear is via visual inspection.
Take a very close look at the engage cogs on the front of the second speed gear. 
The cogs need be sharp and crisp without rounding at the points.
That is most commonly the problem found with the second speed gear.

Let’s say then that the second speed gear is acceptable.
In that case one should put the shift tower into position and shift the T90 into second gear. 
Next carefully remove the shift tower by lifting it straight up.
Notice exactly how far synchronizer sleeve is engaged onto the second gear engage cogs. 
If not fully engaged then the problem certainly lies with the shift tower assembly.

There are basically 2 other issues that may also effect gear. engagement.
Condition of the synchronizer plates and excess end play of the main shaft.

I appreciate the information. And I apologize for being a bit gruff in my response to DMusil. 
 My Dad, my uncle and myself rebuilt the transmission using a kit from KaiserWillys about 4 years ago. 
Everything in the transmission was replaced and while admittedly I don't remember the specs, everything was acceptable  and the transmission put back into service. The shift forks showed some signs of wear but did not appear to be a problem. Obviously we were mistaken.
 My Uncle owned the Jeep at the time and drove it very little. It had been popping out of second for many years and he was used to it and accepted it. He didn't care that it still popped out of second.
I now have the Jeep and I would like to get the issue fixed.
 I will double check the condition of the second gear to see if the problem with the shifter may have damaged the new gear.
 

 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DMusil Quote  Post ReplyReply Direct Link To This Post Posted: 18 Oct. 2021 at 8:39am
My skin is very thick.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 18 Oct. 2021 at 10:09am
Most commonly I would say that the synchronizer plates are the issue. 
The synchronizer plates are cold formed from approximately  10 gauge sheet steel. 
The ends of the plates frequently break off. 
This causes slop in the position of the synchronizer sleeve relative to the second speed engagement cogs.
I would expect the synchronizer plates to be intact at only 500 miles use.
Perhaps you can get a look at the six ends of the three synchro plates via rotating and shifting the synchro sleeve fore and aft ???

Secondly it is quit common to find the engage cogs rounded off on the second speed gear.
That can readily be seen.

Thirdly I would say the the tower has issues.
Here usually it either has broken poppet springs or the forks have become worn thin. possibly a fork has become loose of some other issue.

Lastly I would be concerned with excess main shaft end play. 
This could be the case by worn out or by installing an unknown quality aftermarket mainshaft bearing. (Fafnir 307K)





Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963)
Zero aftermarket parts

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