3rd Gear Blocker Ring Wear

[calvinhunt]

I did use NOS blocker rings from Pete DeBella.  I expected a long-lasting application.  I might still be okay.

[athawk11]

Calvin,
Hopefully I'm not offending, but I'm about to pirate your thread a little.� Although, it may help us both.� I just completed my T-90 rebuild.� I measured things prior to tear down, then after rebuild.

Step 5 above...prior to T-90 rebuild� .007 gap.� After rebuild...virtually no gap or movement when I pull 2nd gear forward.� This has me a bit concerned.� .003 is a pretty small gap, but I don't think I even have .001.

Blocking ring gap...� Prior to rebuild....� .018 for 2nd and .032 for 3rd. (note: my reason for the rebuild was a slight grind going into 2nd)� � After rebuild, the gaps on both rings are in excess of .045.�

The wire springs that hold the 3 dogs are very stiff compared to the set I removed.� Prior to rebuild, I was able to shift the clutch hub back and forth by hand.� After rebuild, I can't slide it back and forth by hand.� It does shift back and forth when using the gear shift lever and fork.� I'm not sure if this is a good thing or a bad thing.

End play on output side prior to rebuild...� I had .008.� Most of this movement was in the rear bearing.� If I held the inner race with a clamp, I had zero end play.� After rebuild, (new bearing)� I have no end play when clamping the rear bearing to the case.�

Everything is turning and shifting freely, but I expected to see some movement.� I plan to install the TC tonight so I can check clearances and movement with it all fully assembled.

Any thoughts on above information would be helpful.

Again to Calvin, Hopefully my jumping in will help us both.

Tim� ��

[1955CJ-5]

I just changed the transmission oil for the first time (500 miles)since it was rebuilt, and I noticed a tint of brass in the oil. I expected that..

So I'm thinking those blocker rings will initially wear in pretty quickly, and the various gaps will either widen or close a little....

Tim, I'm not sure what I would do in your case, but I do know that in my blissful ignorance I checked none of the gaps/clearances and it seems to be working fine....so far

[Ryan_M]

I do know that in my blissful ignorance I checked none of the gaps/clearances and it seems to be working fine....so far

x2...on two transmission so far. Problems are so much easier to handle when you are not aware they even exist.

[zooke581]

I didn't check any play on  mine either.  Just use the bearing and seal rebuild kit and hope to get it in this weekend.  2nd and 3rd are stiff as well and can only shift with the shift tower in.  But it loosened up some after several shifts.

[Carls_jeep]

Some say, what you don't know can't hurt you.

[calvinhunt]

Tim, no worries, totally okay.  As far as thoughts about your tranny being too tight, I mentioned that my second T-90 overhaul, the one with the all NOS gears, shafts, bearings, etc., was tight.  I blamed that on wearing out my 3rd gear blocking ring.  I don't blame that any more. I indicated in my initial post on this thread that George from Army Jeep Parts, who overhaul trannys for customers everyday, told me that if it turned freely in all gears I shouldn't have a problem with it being too tight.  My next dis-assembly just to install new blocker rings, I chose to leave it loose and now regret that.
I must say that what Randy, Ryan, & zooke posted above makes a lot of sense.  Most T-90s are overhauled using kits and components readily available and most of them do just fine without any extra shims or specials efforts to determine end play.
NOTICE: I didn't include Carl in the list because whatever he has to say doesn't count.  He is already in Arizona (coming up my way soon) on a 8 to 10 week Jeeping Holiday.  So his mind is presently out of touch with reality.  Watch for posts with photos of his escapades while out here in the West.

[Carls_jeep]

What? Just because I am traveling I don't know what I am saying?

The closer the shafts are together the less clearance between the synchronizer assembly and the second gear cone the blocking ring fits on. The clearance between the shafts has no effect on third gear blocking ring at all.

I simply can't go along with the, "If it turns freely it's ok", statement. Personally I would prefer to have at least .005" clearance between the shafts to allow for expansion of the shafts length wise. The ball races will allow some length wise movement but only a couple of thousandths and you don't want to bind up ball bearings or needle bearings. There is some movement on the shaft for the synchro assy and second gear and that's the reason you don't want the clearance to loose or to tight.

If my memory serves me right the clearance for a new blocking ring on a new input shaft or second gear is about .050". If you set the clearance at .000" then when he shafts expand the blocking ring will be forced on the cone of second gear. In the long run it will cause wear on that blocking ring.

When the blocking ring and/or the second gear are worn then the shifting collar can't move the blocking ring far enough to the rear to match up the gears as it's supposed to. That is when you will experience jumping out of second and hard to shift into second.

Here's a suggestion for one of you building his tranny now. Hone out a rear bearing to slide on the output shaft and set the clearance to .000" and then see how far you can move the second gear blocking ring off the second gear cone and report back.

By the way, you have to leave the nut off the rear of the output shaft to measure the movement of the shaft to get the clearance.