What’s Wrong with my Transmission...and Other Stuff

Lookout Ranch said:
I had the chance to pull the transmission after work this evening, and it told a tale.

My method for pulling the T90 is to replace the top right and lower left bolts with long ones. I then remove the other two and slide the transmission back on the long bolts to clear the pilot bushing cleanly. (I use the same technique going back in.)

Anyway, the tale the transmission told is best shown with a picture.

View attachment 77671

Yes, the front bearing retainer is very loose, the bolts having worked their way out a considerable distance, and I believe I know the cause (my fault, of course), but that will have to wait till I’ve had a chance to inspect it more closely. You can also see where the retainer and the throw out bearing were rubbing as the retainer moved.

Meanwhile, after seeing that, I was very glad my son and I turned back when we did and made it home OK from Central Nevada in that condition.
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Found a serious problem.
 
The loose front bearing support is a good amount of your problem. If the input shaft moves forward, or more commonly the mainshaft is a bit too far to the rear, the synchro rings will jump out of engagement with the little steel keepers and spin. Usually the steel keepers break off if the synchro moves too far out.
 
Herk said:
The loose front bearing support is a good amount of your problem. If the input shaft moves forward, or more commonly the mainshaft is a bit too far to the rear, the synchro rings will jump out of engagement with the little steel keepers and spin. Usually the steel keepers break off if the synchro moves too far out.
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At his point in time if you are able. I would disassemble the entire transmission and check every part for defects as well as verify serviceability. Then reassemble with any new parts if needed, new bearings and new seals. Something that I have learned about seals. The original seals often were only single lip seals . However as time has gone on SKF for instance has updated the seal and has a double lip seal available for the same application. Sometimes the only way I have ever found the updated seals is to look in the SKF seal book and/or call SKF to verify. The other updates for seals is material from neoprene to Viton for instance. Viton is much better and longer lasting than neoprene in most applications. I learned this reading the seals available based on the original number.
 
You may also want to remove you clutch, pressure plate and throw out bearing to make sure there is no damage to them. You will want to completely degrease your pilot bearing. You will also want to inspect and measure it to verify it is still in tolerance.
 
I've rebuilt hundreds of standard transmissions (mostly Warner) and have never seen that problem. I'm pretty sure what went wrong as well. Thanks for sharing Carter

diggerG
 
I've rebuilt hundreds of standard transmissions (mostly Warner) and have never seen that problem. Thanks for sharing Carter. I'm pretty sure what went wrong, I've been there done that myself. We all have!
diggerG
 
Back to the engine main bearing issue.
I put some reference material in the Library forum.
The reference material says the rear main bearing with the thrust faces is 1.632" long. This appears to be based on a TRW bearing - standard size.
Interestingly, a brand new Federal-Mogul bearing for a 10-under crank is only 1.629" long. (It has the lower thrust bearing face, like the one in my wagon.)
The old used "spare" bearing of unknown brand for a 20-under crank is 1.628" long.

I've ordered a set of Mahle Clevite bearigs that I'm guessing will be sized closer to the TRW spec and more like the old spare. I also found a set of NOS TRW bearings that were cheap enough on eBay that I feel it was worth ordering them as a back-up option.
 
Forgive me for not re-reading the whole string, but did you ever measure the actual end play before disassembly? The few thousandths your chasing in bearing differences may not make much of a difference, considering your statement that you could actually watch the crank moving fore and aft as the clutch was engaged/disengaged. Wishing you success...……….
 
Seabee said:
Forgive me for not re-reading the whole string, but did you ever measure the actual end play before disassembly? The few thousandths your chasing in bearing differences may not make much of a difference, considering your statement that you could actually watch the crank moving fore and aft as the clutch was engaged/disengaged. Wishing you success...……….
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The end play with my current (worn) bearing is 23 thousandths. I can make up at least 18 thousandths of that with a new bearing of the proper size.
 
Lookout Ranch said:
The end play with my current (worn) bearing is 23 thousandths. I can make up at least 18 thousandths of that with a new bearing of the proper size.
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The bearing width is a standard dimension ....so if you are reading the back and plan to use an "0.020" bearing it will not change that end play for you. I only say this because you are not saying you compared the old to the new width of the thrust bearing
 
Here you can see the difference in the heights of the main bearing thrust faces.
The first picture shows the Federal Mogul bearing on the left and the Mahle Clevite on the right. Both are for a 10-under crank.
FAA3B1ED-8C53-4755-86AD-54175F09C6FC.jpeg

The next one shows the old 20-under main, from the Kaiser block, on the right. It’s hair taller than the Clevite. Still don’t know what brand it was
056AA16A-8D26-4DAE-A736-D7C4181BD434.jpeg

After careful measurement of each of these the length of the Federal Mogul and the Clevite appear to be the same at about 1.629”. The other old bearing is 1.630.”

You’ll recall from the table posted above, the spec for a new bearing length (per TRW) is I.632”. I’d sure like to find one that meets that spec. It would bring my end play to within 5 thousandths, and spec is 3-6, if I recall correctly.
 
Lookout Ranch said:
Here you can see the difference in the heights of the main bearing thrust faces.
The first picture shows the Federal Mogul bearing on the left and the Mahle Clevite on the right. Both are for a 10-under crank.
View attachment 78104

The next one shows the old 20-under main, from the Kaiser block, on the right. It’s hair taller than the Clevite. Still don’t know what brand it was
View attachment 78105

After careful measurement of each of these the length of the Federal Mogul and the Clevite appear to be the same at about 1.629”. The other old bearing is 1.630.”

You’ll recall from the table posted above, the spec for a new bearing length (per TRW) is I.632”. I’d sure like to find one that meets that spec. It would bring my end play to within 5 thousandths, and spec is 3-6, if I recall correctly.
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That engine will live with end play but.........if I could get it close or under 0.10 Id be happy .
 
Hey Carter, I might be missing something here, but shouldn’t the crank end play be set by thickness of sides of that bearing as opposed to the height? I don’t understand how the height would change horizontal play of the crank. I know the machine shop that did my crank stated that they would check the polish of that section and ensure they didn’t remove too much.
 
Rustynuts said:
Hey Carter, I might be missing something here, but shouldn’t the crank end play be set by thickness of sides of that bearing as opposed to the height? I don’t understand how the height would change horizontal play of the crank. I know the machine shop that did my crank stated that they would check the polish of that section and ensure they didn’t remove too much.
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You're right, of course. Perhaps I wasn't being clear. My wish for height is to to provide more thrust face surface area that might help those faces wear better. You'll recall the bearing I'm replacing is a short one and has worn down on the thrust faces, creating all that end play.
 
Didn't make a lot of progress this weekend, but did do some clean-up and prep that should help move things along in the next stages.

I could use your advice and counsel for when it comes time for reassembly. As you know the combined package of rear seal, front and rear filler blocks, neoprene oil seal, and the oil pan is a rat’s nest of interfaces between different materials and surfaces that all have the potential to leak oil even when assembled carefully.

What works best in terms of techniques and sealants for the various components?

I've been looking at the Permatex sealants guide but am as unsure as ever which sealant or combination of sealants should be used at various points.

https://www.permatex.com/product-category/gasketing/gasket-sealants/
https://441py33rout1ptjxn2lupv31-wp...2016/03/2016-Product-Guide-GasketDressing.pdf
 
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