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u-joint replacement

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fishndad

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I just picked up a used upper gear box for my AQ275 (mine is toast). The universal has enough rust that I want to replace the spiders. Seems like a bad idea to knock out the old ones with the u-joint assembly still connected to the gear box, and all the manuals seem to show it pulled out. I've read other posts about a gear box swap, and comments suggest any time you crack open the gearbox you should re-shim. For this section however, it seems the shims are part of the bearing pack. If I'm just popping the box open and pulling the u-joint assembly out, do I really need to go through the shimming procedure for that section?
 
When you get the bearing box out, you'll notice some small shims within the seal surface wear washer.
These must go back in if (key word IF) the seal surface wear washer is NOT replaced.

Try your best to polish any rust from this surface. You can take up to .004" or so from this without harming anything.
The new seal will have an approximate .030" squeeze on a perfect washer....., so .004" off won't matter.

Now, if you must replace this washer, the dimensions are not the same.
This means that the shimming procedure must be done.... (i.e., setting the bearing rolling torque value) and this shim value will change.

There is a very thin O-ring that fits into a small groove on the FWD side of this seal surface washer..... between the washer and the male yoke face.
It too must be replaced.


NOTE:
I this is a 275A, the BB will be one piece aluminum. This requires a certain procedure re; way that it is sealed when going back together.
It will require a single O-ring specific to the A transmission.

If this is a 275, the BB is steel and with an aluminum clamping collar. This requires much more attention re; sealing the bolts and bolt threads and mating surfaces when going back together.
It will require two O-rings specific to the Pre- A transmission.

If you need help on any of this, I can send you to an on-line service manual, or we can do it here.


If this is indeed a 275, and if the bearing cross caps are clipped internally, then the new bearing crosses can be a Spicer 5-1306X, and for about $14 each.
Same good quality and the grease fitting is in the apex of the cross just where you want it to be.

If the universal shaft assembly has been changed at one time to the externally clipped caps, then this is a different bearing cross.
I have a p/n for this cross.


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Thanks for a really great description. It is a 275A, replacing an SP-A. I have a Volvo shop manual though it seems to be a reprint, and the pictures aren't all that clear. Fortunately I also have a Seloc and a Clymer manual for this setup too, so I should be able to figure it out.

I think I understand the bearing loading shim process if I do have to change that washer. What about the shimming that sets the gear meshup using the gear marking dye process - I should be able to leave that alone for what I'm doing, right??

I'll hopefully pull it a part this weekend to see what's up. Thanks again, this is very helpful!
 
You are very welcome.

OK... since you have the A drive (as in 275A), the BB will be an intergrated aluminum BB.
All transmissions including and after the A are this style.... 275A, SPA , DP A, DP B and so on.

This means that the bearing pre-load will be crush sleeve controlled... (i.e., no shims within the seal surface washer).
You can replace this seal surface washer without affecting the rolling torque (unlike the earlier transmissions).... but the catch is..... the sleeve "crush" will affect the rolling torque value.

The book will suggest that a new crush sleeve be installed.
However, if you are careful, the crush sleeve can be reused by slilghly increasing the rolling torque value.
The OEM service manual will give us rolling torque values for both "new" and what they call "run-in" bearings (i.e., used and re-usable bearings)
This means that the original crush sleeve will be further compressed, but not by much.
That's the key if you are to do this.
If you can't make the value, then you will replace the crush sleeve and begin again.


You'll also see inch pounds and circular string line rolling torque procedures mentioned.
If your specs suggest spring scale values, then use a string line and scale.
String line/spring scale uses the BB circumfereance as the means of load point to roll the bearings.

If your specs suggest inch pounds, then the inch pound torque wrench procedure must be used.
Inch pounds uses center rotational force to roll the bearings.

DO NOT confuse the values between these two methods... they will not render the same rolling torque values if confused.



Being an A transmission also means that the BB shims are a gasket style shim between the collar and the main gear case.
You will be able to R&R the BB without any change to gear pattern unless you were to replace the two tapered roller bearings.
Even then the change would be minimal, but must be checked.

Use sealant on the four bolt threads.
Bring all four bolts down together until the gap closes to about 1/4"- 1/8" or so.
The sealant will ooze out of the threads and will help seal around the four bores in the collar and the gasket area.


As for gear pattern and/or contact, if you want to you can take a back-lash reading before you pull it apart.
No need to check pattern with die unless you suspect an issue.
If you take up back-lash with the main drive gear, technically you should also take up some with the two driven gears.
This would mean reducing the shim value between the bearing retainer and gear case.
However, this changes the shim control both "Under" the transmission and "Between" the upper bearing and top cover.
For these two areas, what you remove from one side, must be added to the other!
I'd not worry about it unless you suspect an issue!

This sounds more complicated than it actually is. You'll do just fine.


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