Driveline lubrication on 4*6 Mogs?

[Andrew_G]

How are the drive lines (inside the torque tubes) lubricated? I know there is a u-joint at the ball socket end and a spline at the differential end that must need lubrication. There is a grease zerk fitting that appears to just lubricate the ball and socket joint, but (I'm guessing) not the u-joint. No mention of any maintenance requirement in the Case manual either. Is the u-joint lubed with oil from the transmission rather than (typical in other cars) a grease fitting?? It's hard to tell from the exploded parts drawings what is a shim or a seal. There's a vent tube between the diff and the torque tube, so there must be a seal in there. If I understand correctly, the torque tube is one part of a long venting chain (portal to axle housing to torque tube to trans finally exiting via the curly vent tube on top of the trans) so it must be open at the trans end...so oil can get in the tube?
If there is indeed oil in the torque tubes, I'd like to get a sample of it, but I don't see a drain plug. Appreciate any words of wisdom from the forum. It's been a great resource (reading a lot of old posts) so far. Thanks!

[DokaTD]

U joint is lived for useful life from the factory. The splines do not require more than the assembly grease and oil that wicks up into it from the diff.

The torque tube should be dry, if not you have a leak.

[Andrew_G]

Ok, thanks. I suppose since it's well protected from the environment that makes sense (compared to more typical exposed drivelines). If I wanted to verify that the tube is indeed dry, I suppose I could just crack the joint open at the low (diff) end and see if anything comes out. Anyone see any problems in doing that? I'm concerned about water being in there since I had a leaky axle seal and there was some water in the diff. I think it's unlikely that any water would have gotten that high to propagate into the tube, but I have the front axle housings removed at the moment, so now's the time to check.

[DokaTD]

It's certainly possible that you have/had water in the torque tube, but you would have had to go through fairly deep water or had a lot of condensation. Regardless, any amount of water in the tube will drain off into the diff eventually. It's not of much concern. Plus the torque tubes usually have at minimum a small amount of oil in them that usually protects the tube from extreme rust.

[hammogger]

Hi Andrew,

Of course you are aware that if the bolts holding the torque tube to the diff are loosened enough to drain anything, bad things could happen. If you manage to loosen the bolts too much, the rear axle could flop over. That's not a good thing :-)

There has been a mod posted on this forum where a hole is drilled into the bottom of the torque tube, low end, to drain it. Have to be careful to not hit the lower oil seal so don't do that in the blind. A search might find that info.

BTW, if you search about U-joint lube you may find a confusion factor because some 404's did 'leak' a little trans lube into the driveshaft flange and into the U-joint. There is an opening in the tranny output flange and a small fiber filter was fitted there. It served to limit lube flow too.

406's have a plug in the flange hole on all that I have seen. Interestingly, however, 406's still call for the o-ring between the output flange and the U-joint flange, supposedly to keep the non-existing lube from leaking out?. Maybe earlier 406's had U-joint lubrication too??

Concerning the pressure plate bolt torque, MB typically says always use new bolts and for a given bolt the setting torque is given, then an additional angular degrees tightening to stretch the bolts properly. I don't find actual torque specs either. Bet every one of us who have rebolted a pressure plate has re-used the bolts. If that's your intention, why not check a generic torque chart for the size and grade of those bolts and tighten accordingly. Clean them and put Locktite on them as assembled.

Bob

Originally Posted by Andrew_G

Ok, thanks. I suppose since it's well protected from the environment that makes sense (compared to more typical exposed drivelines). If I wanted to verify that the tube is indeed dry, I suppose I could just crack the joint open at the low (diff) end and see if anything comes out. Anyone see any problems in doing that? I'm concerned about water being in there since I had a leaky axle seal and there was some water in the diff. I think it's unlikely that any water would have gotten that high to propagate into the tube, but I have the front axle housings removed at the moment, so now's the time to check.

[Andrew_G]

Thanks Bob for the reply. I'll look into the torque tube drain plug thread. I'm trying to avoid taking everything apart and only get into the necessary things to re-commission this truck which apparently sat idle for some time. I'm going to crack the torque tube joint trying to avoid disturbing the pinion gear seating. If nothing comes out, I'll put it back. The axle tubes are already removed, so I just have to watch the center section - thanks for the cautionary words. All of this stuff is heavy.

I think your comments regarding the pressure plate bolts were intended for someone else, however. I hope my clutch is ok.

By the way, I noticed that you have quite a collection of Mogs. I'm a bit overwhelmed getting my "fleet" commissioned and in road going condition. How do you manage?

[Snow mogg]

I come from th MX bike world where we take a bike apart down to nothing then rebuild every couple races, That said I like to take anything apart sometimes for no real reason, I took my rear axle out the way you are doing it it is very easy. A few strange things I found the pinion gear and ring gear on my truck are not a matched set, also there was only one paper thin spacer inbetween the pinion carrier and the diff center housing? watch out its hard to see and easy to destroy. like hammer said the axle likes to flip over fully assebled. Once you take diff housing off the pinion watch out because the diff and ring gear will come crashing down and break anything in the way hand included. If your in there do the locker seals no matter if they work or not, and use lots of RTV.