Front Differential Help

[SycloneAndSHO]

When I test drive the truck and hit the brake, primarily when I am going down hill, I hear a rattling/clunking sound coming from underneath the truck. So I jacked up the truck and noticed the driveshaft, where it connects to the front diff, was very shiny, and had been rubbing against the transmission. But only when I apply the brakes. So the pressure of the front wheels stopping had been pivoting the differential, and causing the driveshaft to rub against the truck. Has anyone had this problem? I figure the mounts are shot for the differential, and need to be replaced. Unless I'm missing a mount? There's only one place where it is mounted, which is right above where the drivshaft connects. Are there supposed to be any other places where it's mounted?
Also, when I steer the truck, the tires skip, A Lot. As if it were a locked axle. All 4 tires. Is it supposed to do this? And when I got the truck, I got new front axles and wheel bearings with it, since the front left axle had been broke. I'm wondering if that's how it got broke. I'm afraid I'm going to break something taking tighter corners.
Any help is greatly appreciated, thanks!

 

[Don W.]

Re: Front Differential Help

And there are 4 mounts for the front dif. The one you see by the u-joint. One on the front of the dif that goes up to amount on the frame rail, drivers side. And two on the pas side supporting the axle tube over to where it connects to the right half-shaft.

Can you post a pic of the area showing where the driveline is polished and include the surrounding area as well?

 

[dgoodhue]

Re: Front Differential Help

The shiny axle is probably from an upgrade front prop shaft. They make aftermarket shift levers that have little more clearance to avoid that or you can bend your original. I would not be surprise if the front proper shaft failed from the locked vicious transfer case above. With a little of luck you front differential isn't damaged yet.

 

[SycloneAndSHO]

Re: Front Differential Help

And there are 4 mounts for the front dif. The one you see by the u-joint. One on the front of the dif that goes up to amount on the frame rail, drivers side. And two on the pas side supporting the axle tube over to where it connects to the right half-shaft.

Can you post a pic of the area showing where the driveline is polished and include the surrounding area as well?

I can only see one mount and that is by the driveline. I'll post pictures pretty soon when I figure out how. I need to send them some where I guess so I can use the URL

 

[SycloneAndSHO]

Re: Front Differential Help

So my tires in the front are different from the tires in the back. 245/50R16 97H rear, 225/50R1 92V front. So I figure I'll be removing the front axles and only use RWD? Am I going to be able to rebuild / replace the V clutch, or rebuild the differential? I've rebuilt many dirt bike engines, one VW bug engine, and did head gaskets on my 01 ram 1500. So I'm pretty mechanically inclined. The guy I got it from said he had the front end rebuilt a while ago too.
I'll post pics here pretty soon.
I'm gonna resort to youtube and see how a v clutch works lol

 

[dgoodhue]

Re: Front Differential Help

The viscous coupler is a sealed unit. It looks relatively easy to rebuild. The 225/50 and 245/50 are no no for the transfer case.

 

[SycloneAndSHO]

Re: Front Differential Help

Take the front driveshaft out. They do great burnouts with it out. Your clutch is already locked up. You can leave it that way forever if you want. RWD for life. You just won't have one of the coolest attributes of a SyTy: 0-60 in 4.x seconds.....................even in the rain.

You can not remove the stub-shafts that go through the wheel bearing and drive it. Shouldn't really even roll it around the shop with them out. The shaft and big nut hold the bearing together.

The guy I got it from is telling me that the front differential was rebuilt about 100 miles ago. And i figure thats why some of the mounts are missing. Do you think it may still be ok? I'm definitely removing the driveshaft for know until I get it fixed and new tires.

 

[Quickstop [UK]]

Re: Front Differential Help

Sorry for the hijack but where can one get the shift lever for the 80 that takes up less space? I also remember having to grind down the nut that held it on the shift shaft...

Thanks!

 

[Don W.]

Re: Front Differential Help

He sent me some pics and it looks like the drivers side motor mount has failed allowing the motor to settle down and rub against the front u-joint.

 

[Don W.]

Re: Front Differential Help

My trouble is I need to see it. The one other pic he sent shows the lower drivers side mount centered on the bolt BUT without the little outside support. Which, to me, means the front dif has been out. Who know what was done to it. Like Dave said, with the driveshaft removed and one wheel off the ground the dif should turn freely. You can also check "backlash" by rotating the pinon flange back and forth. You should be able to turn it only slightly before you feel it begin to turn the ring gear. IOW with the tire still off the ground virtually ANY motion on the pinion should result in the tire rotating.

Those two tire sizes are "only" about 2% different. Or .81 different if you go the other direction. The vicious clutch may or may not handle that.

Somebody want to wiggle under their truck and measure the distance from the pinion flange to the bell housing. This looks like about 1". Are we that close?

X2 on everything else Dave said as well.

 

[SycloneAndSHO]

Re: Front Differential Help

So I got the driveshaft removed. I had all 4 wheels off the ground so I could turn the driveshaft and access all the bolts. When I got it removed, I turned the part that goes into the differential, and the tires barely turned. Every half turn or so I the tires would move a little bit. I could not hear or feel any roughness when I was turning it. I turned the tire, and it felt smooth aswell. I took the truck for a test drive and no more tires skipping or clunking / rattling sounds like its going to fall apart. The truck drove very smoothly and was quite fun to drive. I forgot to check the lube level, I'll do that tomorrow. Also someone mentioned that it may not have the proper fluid in the differential. Could this be a reason for this issue? Not that it matters too much right now since that driveshaft isn't going back on until all new tires.
I'll get more pics and jump on the laptop and get these things uploaded tomorrow. Ill get some pictures of the engine mounts too

 

[Don W.]

Re: Front Differential Help

If you can turn the pinion shaft/flange and the wheels don't turn the front dif is probably toast. Jack only one front off the ground. Try to turn the pinion flange. does the wheel turn? It should.

 

[SycloneAndSHO]

Re: Front Differential Help

If you can turn the pinion shaft/flange and the wheels don't turn the front dif is probably toast. Jack only one front off the ground. Try to turn the pinion flange. does the wheel turn? It should.

So I jacked one front tire into the air and turned the flange on the front differential, and the tire in the air turned smoothly, either way I turned the flange. I stopped the tire from turning with one hand and tried turning the flange and couldn't turn it, with the tire stopped. So I figure my differential may not be toast?

 

[Don W.]

Re: Front Differential Help

Sounds like it...