T-90 question

After you assemble the second speed gear and then the sychro. assembly on the mainshaft and apply the snap ring, how much end play should you have? I can get a .020 feeler gauge between the second speed gear and the mainshaft shoulder, which seems excessive. Is there thicker snap rings or shims to adjust this?

Thanks,

Randy

 

i have two t-90s with the shifter off one has .002 the other .003 is somthing worn?

 

"After you assemble the second speed gear and then the sychro. assembly on the mainshaft and apply the snap ring, how much end play should you have? I can get a .020 feeler gauge between the second speed gear and the mainshaft shoulder, which seems excessive."

In past experience I have had no problem with a gap as large as 0.012" inches, however the gap cannot be large enough to allow the blocking ring to rest on the mainshaft shoulder.

Check out Rick Stivers T-90 guide for a reference:

http://www.willystech.com/wt/T90RebuildGuide/T90rebuild.htm

 

Thanks for the replies, the measurements given will sure help. As far as things being worn, the second speed gear and sychro. set is all new. The mainshaft was reused. Not sure where the slack is coming from, sounds like I need to get it down to at least half of where I'm at. How could I adjust this if I can't find anything obivous causing the excessive end-play?

Thanks again,

Randy

 

Hi,
I have run across snap rings of varying thicknesses in three different kits that I've used on t-90s in the past, so that could be a problem, you may want to check the thickness against the original. Also, many transmissions use variable thickness snap rings to adjust end play and clearances, such as the input shaft snap rings on the t-98s and t-18s.
Hope this helps some,
Daniel

 

Thanks, that's what I was wondering. I generally don't work on stuff this old, but on newer transmissions that I have worked on that's exactly how they adjust for endplay. My problem is I don't have the original and my kit only came with one. Is there some place that sells the different thickness snap rings individually, I could measure the one I got and add what I need to remove from endplay? If anybody has a source please post.

Thanks again for all the help,

Randy

 

just for your information, there is no published end play spec for 2nd gear; you won't find different snap rings for the shaft; there is only one listed for the T90, and the factory spec on it is: .086 to.088 thick; you might mic yours to see what it measures. (some kits might give you some to choose from, but fom Jeep, there is only 1 part number listed)
it's true, with other trans (T86, T14 T15) you could get a selection of snap rings.
I have seen all kinds of shims added to make up for some of this play; small pinion shims are the most popular.
every old time Jeep mechanic had his own way with dealing with this potential problem; most crossed their fingers and hoped it wouldn't pop out of gear......but that is another story ...

 

One other thing that I wanted to mention, if you decide to ad a shim, keep in mind that most pinion and axle shims are thin and not really designed to handle the thrust presssure of a gear that is spinning on them, they can easily split and crack apart under pressure if they are loose in an assembly especially if they are thinner than .010". I have seen it many times in transfer cases and axles that I have rebuilt and repaired after the pinion nuts loosen or the t-case output shaft nuts loosen. Pinion shims are designed to be clamped tight between the pinion shaft and the pinion bearing with virtually no relative motion between them. The thinner the shim the more prone to damage it is.

As a side note, I rarely use less than a .010" shim for pinion preload because of the extreme pressures that these shims see, I have seen thinner shims split under the pressure required to simply torque the pinion nut!

The best bet if you want to eliminate some of the end play may be to use a thicker snap ring with no shim if possible, or use a thinner snap ring and the thickest shim you can while still mantaining some endplay. Just something to consider, because I'd hate for you to run into problems after all that work.

Daniel

 

Daniel you bring up a good point.
that's not how I would do it either,
just what I have seen over the years.