T-case rear output bearing slop (1 Viewer)

[Glenn-BJ74]

I noticed my T-case output bearing has been loose (when wiggled) over the last few months and it appears to be getting worse. Its now weeping oil motivating me to have a look.

I pulled out the drive shaft this weekend and undid the staked 32 mm nut. The staked nut is supposed to torqued to 94 ft/lbs, but when I undid the tabs, it came off fairly easily. Underneath the staked nut was a thick washer (0.193” thick). I don’t understand if the staked nut was supposed to be at 94 ft/lbs why was it so easy to undo ??

After pulled off the rear bearing retainer I examined the bearing and race. The bearing and race are not pitted, but their was some minor pitting just inside and outside of the bearing contact areas. I guess this is normal. What I don’t like is the end of the shaft is very loose. At its end the shaft wobbles around in a 1/8th inch circumferential radius, that is about ¼” side to-side.

What is causing this amount of play?

http://www.flickr.com/photos/12208287@N06/3036601397/

 

[crushers]

LOL!!
<okay laughing might not be nice>
the nut was torqued to that spec with a new (no wear) bearing and race, now you have wear which actually reduces the amount of torque remaining against the nut...

 

[Glenn-BJ74]

Yes that is the symptom, but what is the cause?

Having never worked on splitcase I am wondering if this is a sign of something seriously wrong inside.

Thanks in advance to those more experienced than I.

 

[Radd Cruisers]

Yes that is the symptom, but what is the cause?

Having never worked on splitcase I am wondering if this is a sign of something seriously wrong inside.

Thanks in advance to those more experienced than I.

You know, Glenn, we're just up the highway a little from you and we have all the parts and all the answers... the phone works better than email.

If you're mileage is getting upwards of 200K then you might want to consider a re-bearing of the case (we have numerous kits in stock, all have Koyo bearings). If yours is a low mileage truck, then you can try to re-shim and install a new seal. A new nut is a good idea...

This is normal wear issue. The bearings wear slightly over time and lose their preload, causing play in the shaft. It is important that it gets fixed or bad things can happen if you let it go too long.


~John

 

[crushers]

its wear, how many km on the t/case? how much mud and water has it seen? last time it saw an gear lube change? lift?
any or all of these can cause the t/case to have premature output bearing wear...

 

[crushers]

don't shim the old bearing, rebuild properly with new... if the rear output is worn then so is other internal parts...

for me, if it is a long distance hauler or a DD then rebuild, if it is a bush pig (depnding on the degree of wear) then drive it. you will be rebuilding it more often as a bush pig. my bush pigs get a rebuild usually about every year, depending on the mud i have played in...

 

[Ron R]

I may be wrong here, but the all the stakenut does is bolt the flange to the outputshaft.
The bearing load is set by the shims in the housing. Even if the nut is off you can check the bearing load, but then, the manual instructs to put the nut on to check the bearingpreload by means of a torquemeter. The nut is needed to use the torque meter to find the preload.
If the preload is off, shims behind the outer race - inside the bearing retainer - are used to adjust.
Only after adjusting the preload (without the flange installed) the flange should be installed and the nut torqued to spec (1,300 kg/cm or 94 ft-lb or 127 Nm)

So if there is play in the bearing this has nothing to do with the flange nut being properly torqued or not.

If you go (are) in there, like John and Wayne are saying, put in new bearings. They are not that expensive and then you're good to go for many k's again.

 

[crushers]

the campanion flange puts pressure on the shims and the stake nut puts the pressure on the companion flange...

 

[Radd Cruisers]

the campanion flange puts pressure on the shims and the stake nut puts the pressure on the companion flange...

The bearing retainer holds the race (cup) into the case and puts the pressure on the output bearings, the stake nut holds the rear bearing (cone) on to the shaft via the companion flange, speedo drive ring, and a spacer. The shims sit in the bearing retainer between the race and the retainer.

The looseness in the shaft is most often related to output bearing wear. Oil loss via the shaft seal is related to bearing wear, and in some cases a loose companion flange (next paragraph).

The rear nut seems to come loose over time and may be related to compression of the companion flange and very slight wear in the splines (improperly seated bearings can cause this). This is aggravated by higher than normal driveshaft angles, use of lockers and larger tires (due to increased stress on the parts), worn u-joints (vibration) etc... Usually oil loss through the spline is associated with a loose nut (mostly noticed when removing the driveshaft).

Often the pinion bearings need attention at the same time as the transfer case. Glenn had ARBs put in, so his diff bearings should be fresh... Lockers & larger tires also aggravate pinion shaft looseness, especially with crush sleeve diffs.

The loose t'case bearing issue usually means you need new bearings, though not always. Having the rear retainer off to inspect the race is required.

I can go on, but I have work to do...

~John

 

[crushers]

LOL!!
yep, my bad. early morning brain fart...

The bearing retainer holds the race (cup) into the case and puts the pressure on the output bearings, the stake nut holds the rear bearing (cone) on to the shaft. The shims sit in the bearing retainer between the race and the retainer.
~John

 

[Glenn-BJ74]

The bearing retainer holds the race (cup) into the case and puts the pressure on the output bearings, the stake nut holds the rear bearing (cone) on to the shaft. The shims sit in the bearing retainer between the race and the retainer.

The looseness in the shaft is most often related to output bearing wear. Oil loss via the shaft seal is related to bearing wear, and in some cases a loose companion flange (next paragraph).

The rear nut seems to come loose over time and may be related to compression of the companion flange and very slight wear in the splines (improperly seated bearings can cause this). This is aggravated by higher than normal driveshaft angles, use of lockers and larger tires (due to increased stress on the parts), worn u-joints (vibration) etc... Usually oil loss through the spline is associated with a loose nut (mostly noticed when removing the driveshaft).

Often the pinion bearings need attention at the same time as the transfer case. Glenn had ARBs put in, so his diff bearings should be fresh... Lockers & larger tires also aggravate pinion shaft looseness, especially with crush sleeve diffs.

The loose t'case bearing issue usually means you need new bearings, though not always. Having the rear retainer off to inspect the race is required.

I can go on, but I have work to do...

~John

Great info John - that explanation was what I was looking for -- that will help others with simiar slop at the rear T-case bearing.

 

[Ron R]

The bearing retainer holds the race (cup) into the case and puts the pressure on the output bearings, the stake nut holds the rear bearing (cone) on to the shaft. The shims sit in the bearing retainer between the race and the retainer.

~John

It may sound a bit picky, however, that is not my intention. All I want to do is a bit of explaination for the interested reader....

I've prepared a little (and simplified) drawing.

The outputshaft has a notch against which the cone (inner race -A) of the bearing rests.
The outer race (B) is held in place by the bearing retainer (C)which is bolted to the casing.
The shim (D) - depending on thickness - presses the outer race race more or less towards the left, thus establishing the preload on the bearing because the races are tapered.
The compannion flange is not drawn but normally sits on the splines (horizontal lines at the right hand side of the shaft) and is secured by the stake nut.

From the drawing you can see that, the companion flange and stakenut being present or not, the inner race cannot move to the right.
Therefore the bearing preload only depends on the thickness of the shim and a properly torqued bearing container.

 

[Joe70]

don't shim the old bearing, rebuild properly with new... if the rear output is worn then so is other internal parts...

for me, if it is a long distance hauler or a DD then rebuild, if it is a bush pig (depnding on the degree of wear) then drive it. you will be rebuilding it more often as a bush pig. my bush pigs get a rebuild usually about every year, depending on the mud i have played in...

Hey Wayne, what is all included in the T-case rebuild that you speak of? I've never had it done on any of my rigs and you know how we wheel around here. It's probably time.

 

[crushers]

everything you need to do the job right.
contact Dan at 4wheel, he has them in stock and he will ship the same day.

 

[Joe70]

I suppose you have to pull the T-case?

 

[Ron R]

I did a rebuild under the rig. Replaced all the bearings.
Took of the rear and front casing. Left the centre part on the gearbox.
Was not very hard to accomplish.

Most difficult in my opinion was to adjust the bearing for the rear outputshaft.
The manual advises to use the original shim as a start. That proved to be wrong.
You then have a table to find the right shim (they are awfully expensive about 10USD/piece)
Had to order several shims before I had the right one that provided the right preload.

Every time you have to change the shim, you have to take off the bearing retainer and remove the outer race. Put in a different shim, bolt back on check etc.
Top left picture showing the difference between old and new race. Topright the partly dismantled x-fer. Front part still in. Lower picture some of the old rollers (not part of the topleft race.

 

[crushers]

well, you can do it on the truck with the back half removed but i recommend taking it completely off (you have a pit and it is EASY). clean it real well, instll the front parts, reinstall the front half.
of course it still has to go back on the front half first, guts, then the rear half.
i have done too many to remember in that pit...

 

[Glenn-BJ74]

I did a rebuild under the rig. Replaced all the bearings.
Took of the rear and front casing. Left the centre part on the gearbox.
Was not very hard to accomplish.

Most difficult in my opinion was to adjust the bearing for the rear outputshaft.
The manual advises to use the original shim as a start. That proved to be wrong.
You then have a table to find the right shim (they are awfully expensive about 10USD/piece)
Had to order several shims before I had the right one that provided the right preload.

Every time you have to change the shim, you have to take off the bearing retainer and remove the outer race. Put in a different shim, bolt back on check etc.
Top left picture showing the difference between old and new race. Topright the partly dismantled x-fer. Front part still in. Lower picture some of the old rollers (not part of the topleft race.

Good diagram and explanation Ron R -- always been a mystery how that is suppose to work. The manual is very vague on this important adjustment.

 

[Ron R]

Good diagram and explanation Ron R -- always been a mystery how that is suppose to work. The manual is very vague on this important adjustment.

Thanks for the kind words.

I agree on vagueness of the manual.
The value for the preload is not a very broad range and one of the things that puzzled me was the gasket for the bearing retainer.
The way I read it, you should leave the old gasket in place while doing the adjustment. Then after the adjustment put a new gasket on and do the final assembly.

But you also can read it as 'do not use a gasket during the adjustment' and after the adjustment put the gasket on.
Having the old gasket removed during the cleaning process I decided to use a new gasket during the adjustment procedure and replace that for another new one during the final assembly.

Why so a*n*a*l about this gasket?
Well, the available shims (about eleven different sizes) differ in incremental thickness 0.1 mm (0.040 inch). This 0.10 mm alters the preload by about 1 N.m and that is equal to the range in the setting that is allowed.
So compression of the gasket (even if very small) can put you out of the preloadrange when the gasket is being reused and more often compressed during renewed assembly to find out the right setting.

So what I did was establish the needed value and do the final assembly of the bearing reatainer.
Then I checked the preload value once more without the companion flange in place. That being in the right range, I put on the flange.
It's holding now for about 50.000 k's without play and I guess I did it right.

 

[Glenn-BJ74]

Ron R - I think I understand now, except how do use a small 1/4" torque wrench to measure the output shaft bearing torque. The end of the shaft is indented, but how is a small torque wrench attached to such a large shaft. Is there a some special tool avialable to do this - ?