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Topic Summary

Posted by: Carls_jeep
« on: August 07, 2014, 04:00:45 PM »

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.
Posted by: calvinhunt
« on: August 07, 2014, 01:39:30 AM »

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.
Posted by: Carls_jeep
« on: August 07, 2014, 12:37:50 AM »

Some say, what you don't know can't hurt you.
Posted by: zooke581
« on: August 06, 2014, 09:19:43 PM »

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.
Posted by: Ryan_M
« on: August 06, 2014, 08:58:29 PM »

Quote
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.
Posted by: 1955CJ-5
« on: August 06, 2014, 12:21:30 PM »

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






Posted by: athawk11
« on: August 06, 2014, 12:00:53 PM »

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� ��
Posted by: calvinhunt
« on: August 06, 2014, 12:28:01 AM »

I did use NOS blocker rings from Pete DeBella.  I expected a long-lasting application.  I might still be okay.
Posted by: Carls_jeep
« on: August 05, 2014, 11:07:38 AM »

Calvin, I don't think the oil has caused the wear on the third gear blocking ring. It could just be a defective blocking ring. Maybe the brass alloy was not right or maybe it was a bad machine job. It seems like the minimum clearance between brass ring and steel gear is .030" but I'm not sure about that.

The only way I can shift my tranny without a little clicking in second and third gear is to double clutch in neutral. If I don't double clutch the synchros make a little noise when shifting in second and third.
Posted by: 1955CJ-5
« on: August 04, 2014, 10:47:08 PM »

Thanks Carl,

If I rebuild another, or rebuilt this one again, I'll have more knowledge of how it should be and will at least make an effort to do it "right".� Of course that means more tools!! :)

On a positive note the 3a transmission seems to be just fine after 500 miles...and the Cj-5 transmission is just fine after some 49,000 miles from the factory.....But the T/C is a little noisy in low range...
Posted by: Carls_jeep
« on: August 04, 2014, 10:32:00 PM »

1955CJ5, the end play that is alluded to is actually clearance between the input and output shafts. There is no such thing as end play, it's clearance and I wish everyone would understand that.

To find the clearance you have to hone out a good used bearing so the bearing slips on the output shaft. You assemble everything and clamp the bearing retainer plate to the back of the tranny housing. Then with a dial indicator you measure the distance the shaft slides in and out in the bearing. That distance is the .003" to .014" listed in the service bulletin.

Some bearing retainers stick out from the rear of the case and that is called protrusion and that has to be accounted for with the correct thickness gasket to seal the tranny to the transfer cases. If the bearing retainer is below the surface of the rear of the tranny case the plate and bearing can slide back and forth and you will have more clearance between the shafts than is required.

Due to production tolerances anything is possible so check everything as you build the tranny and transfer cases. Take nothing for granted. I solved the clearance issue by making a bearing spacer to replace the original spacer that was to thin. Not everyone has a lathe to do this so you have to find a source of shims to fix the problem.

Since bearings are made to very close tolerances you don't have to worry about the thickness of a bearing being different. BUT, you do have to use a good bearing without a lot of wear in the balls and races to do the clearance testing.

On the other hand, people do just slap them together and it works, but maybe not very long.
Posted by: 1955CJ-5
« on: August 03, 2014, 11:33:50 PM »

Well I have learned plenty....a T-90 rebuild is much more than just installing a rebuild kit.......

Keep us in the loop.....

Randy
Posted by: calvinhunt
« on: August 03, 2014, 11:28:40 PM »

Randy,

Yes, I did measure the gap between 2nd gear when pushed forward and the shoulder on the main shaft.  Sorry to say it was .025.  That makes we worry that it may not be long before my tranny starts jumping out of 2nd when on deceleration.  That is where the aftermarket shim would fit if one were available.  When that happens I'm going to try to use some 1/4 hard stainless sheets we have at the aviation shop and make one as close to what I remember having so many years ago on my CJ-5.  I hope I learn something from all this. 
Posted by: 1955CJ-5
« on: August 03, 2014, 11:16:21 AM »

Calvin,

I'm glad your transmission is still working well...the blocker ring wear is interesting and if I ever have occasion to remove my tower assy I'll check the gaps on mine..

Were you able to measure the gap between 2nd gear and the shoulder on the main shaft, as mentioned in step 5 of the service bulletin? Just curious of course...

Randy

Edit:...Maybe that service bulletin should be in the FAQ or some other easily accessible location.....
Posted by: calvinhunt
« on: August 03, 2014, 01:49:29 AM »

Thanks Gents,
I appreciate the input and discussion.� I was hoping there would be a "magic bullet" answer about what I've been doing wrong to cause my 3rd gear blocker ring to wear prematurely.� Actually, it still shifts perfectly and doesn't jump out of 2nd, so I'm pleased.� I measured the gaps today: Blocker ring to 2nd gear is .038, blocker ring to 3rd is .019.� Hopefully the wear is slowing and it may serve me well for years to come.
�
Randy, That was certainly an interesting, and yes, spirited discussion you shared from the CJ-2A site.� However, Willys manuals of the time left lots of stuff out.� I'd hate to try to overhaul a tranny just using the vintage shop manual.
�
Tim, Yes, the pilot bearing in the flywheel needs to be in good shape.  I installed a new one each time I overhauled my transmission.  There are cheap ones and good ones.  Use a good one.  I think you'll enjoy overhauling your T-90.� But like I just said, I'd have another source as a guide for your overhaul.� Novak Conversions has a good one and it's available from their web site.
�
Bob, Thanks for posting the old service bulletin.� It is step 6 that we're focusing on here.� As I said, George at Army Jeep Parts told me about the shim.� He has them available as a set of varying thicknesses and they install just as the bulletin instructs.� He also told me to ream out the center of an old rear bearing so that it may slide over the main shaft (output shaft) and be clamped against the spacer mentioned in the bulletin.� Once the desired fit is obtained the new rear bearing is pressed onto the main shaft and the T/C is bolted to the tranny. Like Randy says, the T/C casting fits over the rear bearing upon bolt up.�

Brett, You are right.� When I was 18 years old I had a 56 CJ-5 that jumped out of 2nd gear on compression.� I checked with a Jeep dealer about it.� They had a .030 stainless steel shim (1/4 hard) that fit into the tranny just by removing the shifting tower and placing it just behind 2nd gear over the main shaft.� That moved 2nd gear forward, closer to the clutch sleeve for better engagement.� It was like a horseshoe but it was designed to close it some by bending the open tangs slightly together to retain it.� It took care of the problem.� I had the Jeep for more than a year after that and then sold it to a friend who had it for several years without the problem returning.� The Jeep dealer explained that it was not a Jeep part, rather an aftermarket item.� However, the .030 shim mentioned in the bulletin is installed when the tranny is being assembled with the bearing spacer and the rear bearing.