Broken Front Diff??? (1 Viewer)

lcolon

SILVER Star
Joined
Oct 14, 2007
Messages
461
Location
East Bay, SF, CA
I twisted up my front drive shaft in Death Valley coming down south park canyon, just before 'chicken rock'. I somehow made it out in 2wd and was able to get home back to the bay area.

I pulled my front shaft out and sent it to the shop to get rebuild. The funny thing is that my front diff is acting strange:

I can turn the pinion flange 180 degrees in either direction (hubs unlocked) before feeling resistance. With the hubs locked, I can do the same. I moved the truck back and forth about 15 ft and i could not see the flange turn at all. How do I figure out without taking apart the whole axle whether my diff has any issues? I do not feel any play in the flange. I am not sure how far the thing is supposed to move by itself and whether it should turn when I roll the vehicle with hubs locked....

I searched but.... now I have to post.
0410101734-00.jpg
 
Joined
Apr 6, 2010
Messages
117
with hubs locked I don't believe it should turn at all (with your tires on the ground) as it is then mechanically linked to your tires. With hubs out should turn easily as your turning your axles/diff and not your wheels/tires. With your hubs locked and you backing your vehicle the flange should be turning. Could be wrong but makes sense to me.
 

lcolon

SILVER Star
Joined
Oct 14, 2007
Messages
461
Location
East Bay, SF, CA
Thank you for the advice.... I will compare how the rear diff behaves to the front. Yes it is quite twisted up. I found out (the hard way) that this is a fairly common occurrence when you hit a rock. The drive shaft can collapse as easily as a tin can when you dent the side. Interesting because I have never carried a spare... now I am considering having a second with me (front and rear).

PacToy,

Thank you. Hopefully it is OK. I will probably know at the end of the week.
 

2mbb

SILVER Star
Joined
Sep 1, 2003
Messages
5,194
Location
WC, CA
with hubs locked I don't believe it should turn at all (with your tires on the ground) as it is then mechanically linked to your tires. With hubs out should turn easily as your turning your axles/diff and not your wheels/tires. With your hubs locked and you backing your vehicle the flange should be turning. Could be wrong but makes sense to me.

x2. this is assuming the front drive shaft is not installed or the transfer case is in 2wd and both tires on the ground.

With the hubs "free" the flange should spin around and around with only the resistance of the differential and axles.

When you first lock the hubs, the flange will spin easy for less than one rotation as the hubs engage. When they do engage, the flange should not turn in either direction except for the few degrees associated with the differential backlash.

with the hubs locked and engaged rolling the car on the ground should make the flange turn.

This is not exactly what you describe in your first post. I would drain the differential and check for metal bits before test driving. I suspect something locked up in the differential.
 
Joined
Mar 4, 2010
Messages
198
Location
Gulf Coast
I think you have an issue. With the hubs locked, your flange should turn with the truck over a 15ft drive for sure. Have you got an open diff or locker or what? If you don't have a locker, it may just be a hub issue.
 

lcolon

SILVER Star
Joined
Oct 14, 2007
Messages
461
Location
East Bay, SF, CA
I am running open diffs. I guess there are some more tests in the works to determine what the problem is... strange that the driveshaft collapsing would cause bigger issues in the front end. The truck, thankfully, is not my DD. I will pull it out of the garage next weekend and see if I can figure out what is up.

Thank you all for the advice. I hope it is not something too serious and that I don't have to tear down the front axle. It has already been apart twice in the last 1.5yrs...
 

2mbb

SILVER Star
Joined
Sep 1, 2003
Messages
5,194
Location
WC, CA
I don't think the driveshaft caused that problem but occured because of another problem.

You don't describe the situation that would cause both front wheels to stop rotating while rear wheels rotate.
 

Ducks

SILVER Star
Joined
Apr 5, 2006
Messages
1,905
Location
Portland, Oregon
If your hubs are locked and you roll the truck 15ft, the flange has to rotate. If it doesn't rotate, then there is something wrong with the hubs or something wrong with the axles or something wrong with the diff. Sorry but it has to be that way.
 

lcolon

SILVER Star
Joined
Oct 14, 2007
Messages
461
Location
East Bay, SF, CA
Update - Got my new re-enforced driveshaft back from Gary at Mudrak. It looks great (that is the good news). The bad news is that I grenaded my front diff or otherwise broke something serious. Gary used his special jack (forklift) to lift my front end off the ground. We were able to lock the hubs, spin both tires, and could not feel any movement at the pinon flange. The pinion flange also turns fairly freely.

I guess I now have to look for another 4.11 Third and have the front completely disassembled (third time in two years) to have the diff replaced. Hopefully nothing else got taken out.

What I learned (Gary's advice) - when going down hill in 4low USE THE BRAKE over obstacles and don't bounce the front. I probably put 2.5 tons of truck up against the front diff coming down the rock ledge and destroyed the whole thing. I'll go back to the fact that I was lucky enough to be able to drive out in 2wd.
 

Users who are viewing this thread

Top Bottom