Front Diff Failure (1 Viewer)

[dglenn]

Ok, got the call from my son yesterday afternoon driving the 94 LC. Dad the truck is making a horrible noise, happened when I made a turn, just pulled over and it is really a bad grinding noise when I put in drive.

He was able to limp home idling as he was roughly a mile from the house. He said that the grinding diminished while just underway but would increase with acceleration. I guess this has something to do with the axle catching up to the broken gear and then over riding it?

I had him put in gear while under truck and the front drive shaft is actually turning while the truck is sitting and in gear. I have spent a good amount of time reading through different threads and FAQs. I have a better understanding of how all the differentials work. I have a DIFF LOCK button for RR and FR-RR just to left of my steering column. I do not have a Center Diff Switch. I have ABS.

We need to drive the truck until I can further diagnose, repair the front differential. Can I, remove the front drive shaft, lock the center differential(turn key on, put shifter in 4L, pull diff fuse, shift to 4H) and safely drive.

Or do I risk doing more damage in the front differential?

Second, is it more cost effective to rebuild the front differential or find a used front end and go that route?

Oh and please no comments about the safety of having my kid put the truck in gear while I was underneath, I was very clear that he should not run me over.

Thanks.

 

[Tools R Us]

...
We need to drive the truck until I can further diagnose, repair the front differential. Can I, remove the front drive shaft, lock the center differential(turn key on, put shifter in 4L, pull diff fuse, shift to 4H) and safely drive.

That will work.

Or do I risk doing more damage in the front differential?

Maybe... Where is the noise coming from, the center of the axle, or knuckle area? I would remove the dust caps and see if one of the stub shafts are turning. You could have a broken diff (doesn't sound like it?), broken birf (doesn't sound like it?), a stripped drive plate (most common), etc. Need to figure it out before spending $$$.

... I was very clear that he should not run me over.

Thanks.

 

[LandCruiserPhil]

Ok, got the call from my son yesterday afternoon driving the 94 LC. Dad the truck is making a horrible noise, happened when I made a turn, just pulled over and it is really a bad grinding noise when I put in drive.

He was able to limp home idling as he was roughly a mile from the house. He said that the grinding diminished while just underway but would increase with acceleration. I guess this has something to do with the axle catching up to the broken gear and then over riding it?

I had him put in gear while under truck and the front drive shaft is actually turning while the truck is sitting and in gear. I have spent a good amount of time reading through different threads and FAQs. I have a better understanding of how all the differentials work. I have a DIFF LOCK button for RR and FR-RR just to left of my steering column. I do not have a Center Diff Switch. I have ABS.

We need to drive the truck until I can further diagnose, repair the front differential. Can I, remove the front drive shaft, lock the center differential(turn key on, put shifter in 4L, pull diff fuse, shift to 4H) and safely drive.

Or do I risk doing more damage in the front differential?

Second, is it more cost effective to rebuild the front differential or find a used front end and go that route?

Oh and please no comments about the safety of having my kid put the truck in gear while I was underneath, I was very clear that he should not run me over.

Thanks.

Sorry to hear.
Yes you can drive it but in addition you will need to remove the drive plates on each end of the axle and protect the inners of the hub. This can be done with something as simple as duct tape or a plastic bag over the end secured with electrical tape.

Post up more specs and history on your vehicle.

 

[Eicca]

x2 on checking the hubs for stripped drive plates. Front diff failures are more common among the 100-series cruisers.

 

[CJF]

Waay more likely a birfield (or even just a drive flange if you're lucky) than the diff.

You need to figure out exactly what's broken before driving it any further, or yes, you could cause a lot more damage.

 

[dglenn]

Ok appears the noise was right in the differential where the front drive shaft bolts up to the flange coming out of the front differential. Not sure I follow the bit about removing the drive plates, does that then let the wheels roll free of the axle? Is that as painless as the front axle removal or a lot more detailed? I will get back into the front end after work and with my son in tow around 6:00. Thanks for the feed back.

 

[LandCruiserPhil]

Ok appears the noise was right in the differential where the front drive shaft bolts up to the flange coming out of the front differential. Not sure I follow the bit about removing the drive plates, does that then let the wheels roll free of the axle? Is that as painless as the front axle removal or a lot more detailed? I will get back into the front end after work and with my son in tow around 6:00. Thanks for the feed back.

Yes, without removing the drive plates the diff,axle, and birf with still turn. Removing a drive plate consist of 6 nuts, 6 cone washer, dust cap, and 1 snap ring.

 

[dglenn]

Ok thanks, plan to do a little more diagnostic under the truck later this evening to see if I can verify the noise is coming from the front differential flange area then lock center diff, remove front drive axle, remove the drive plates and get the truck on the road until I can spend some more time with it. I am guessing after I do this and the wheels move freely as the truck is jacked up that I am not risking the possibility of more damage in the other areas, birf, diff etc...?

 

[CJF]

Ok thanks, plan to do a little more diagnostic under the truck later this evening to see if I can verify the noise is coming from the front differential flange area then lock center diff, remove front drive axle, remove the drive plates and get the truck on the road until I can spend some more time with it. I am guessing after I do this and the wheels move freely as the truck is jacked up that I am not risking the possibility of more damage in the other areas, birf, diff etc...?

Slow down.

First step is to simply remove the dust cap and see if the axle is spinning. (No need to even jack the truck up.) Spinning = stripped drive flange.

If that's the problem, then as Phil said: "Removing a drive plate consist of 6 nuts, 6 cone washer, dust cap, and 1 snap ring."

That's it; you're done. Lock the center diff and go.

 

[dglenn]

Got it, thanks CJF, if it is not Spinning = stripped drive flange, then do I still need to remove the drive plate to get her on the road temporarily? Or is it just drop the drive shaft?

 

[Eicca]

If the shaft isn't spinning the drive flange is fine. If the shaft is spinning, then you've got a problem.

 

[kidglove13]

It is probably one of 2 things
Pinion bearing is gone
Or drive plates are stripped

either one of these issues can be bypassed so that the truck can be driven, gotta love a land cruiser

 

[dglenn]

Ok, popped both dust caps and neither the right or left stub end of shaft is turning when we engage the transmission. The sound is really a heavy grinding of marbles. If I have understood the comments so far, my next move is to detach the front drive shaft, fool the cdl into lock position and I can drive her until I get a chance to get into the front differential or do I also need to detach the drive plates to run this way? Thanks for any feedback.

 

[Eicca]

You'll probably want to pull the drive plates anyway so whatever's broken doesn't get ground up even worse by the rotation of the wheels.

 

[LandCruiserPhil]

Ok, popped both dust caps and neither the right or left stub end of shaft is turning when we engage the transmission. The sound is really a heavy grinding of marbles. If I have understood the comments so far, my next move is to detach the front drive shaft, fool the cdl into lock position and I can drive her until I get a chance to get into the front differential or do I also need to detach the drive plates to run this way? Thanks for any feedback.

If you have never removed cone washers do yourself a favor and search prior

 

[dglenn]

alright, thanks guys appreciate the help.

 

[dglenn]

Ok, removed the front shaft and test drove. 25 to 50 MPH, no noise or abnormal vibration from the front end. We have not removed drive plates. Based on test drive, not sure that we need too? Can we rule out everything outside of the front differential case at this point?

CDL is locked, indicator lights on dash look right, diff fuse out.

As we were breaking the nuts loose on the shaft front and rear, we needed to rotate the shaft from a neutral transmission position. It took a lot of pressure with a large screwdriver in the u joint to move approximately 180 degrees to get to all the nuts.

Where the heck do you go from here to diagnose differential if we can rule out the mechanical stuff outside towards the wheels?

Thanks

 

[Eicca]

Pop the diff cover and see wazzup.

 

[kidglove13]

Pop the diff cover and see wazzup.

There is no front diff cover

 

[kidglove13]

I think it is time to pull the diff
You cannot know what it is until you take it out
Something is obviously wrong in the diff
That means that whole front end will need to come apart and pull the axles to get the diff out
If you have to do that you might as well factor in a front rebuild while you are in there if you have not done it
New seals and trunion bearings and repack everything with grease

This would also be a good time for father and son time working in the cruiser
A front end job is not overly difficult and you and or your son could have fun with it
I would leave the front diff work to someone else, diff work is not fun nor easy
I thought I could tear into mine and ended up bringing it to a friend, especially if you dont have the right tools