I have my diff cover off

[Defective]

8.8 with 220k miles.

Started getting a groaning sound and vibration that felt like meshing gears.

I put the truck up and jackstands and the rearend was difficult to rotate the tires by hand. While spinning I could feel a repeating resistance that felt like what I could have been feeling while driving.

The fluid has never been changed, unless it happened in the 32k miles before I got it.

So I drained the black fluid and cleaned it up a bit to see what I had. Everything looks good to me but I've never looked into a differential before for wear.

There is some play when turning the driveshaft, no side/side or in/out play. There is some play in the axle when turning the tires too, not too much, but it's noticeable.

How do I figure out what the noise was? Should I just fill it up with fresh fluid and see if that takes care of it? 75or 80w gear oil right? Does anybody know if Royal Purple already has the required friction modifier?

Thanks!

 

[martin]

check the pinion bearings. If you don't find anything, have someone more familiar with axles to take a look for you. If it was making noise it was doing it for a reason.

 

[kevinsranger]

check the brakes also, if the drums arent off it can be them causing the resistance

 

[Evan]

The play you mentioned is normal, provided it's not excessive.

 

[fordboi415]

Jack up the rear with the cover removed, turn the tires while watching the gears in the differential, make sure there are no teeth missing or broken off, if it all looks good and you can't see any damaged gear teeth then bolt it back up and make sure you replace the cover gasket, I use 85w140 royal purple and yes it does have the limited slip additive in it, worst case senario is that you need new gears and I did the 8.8 swap for about 500 bucks so it was def. worth it

 

[85_Ranger4x4]

Jack up the rear with the cover removed, turn the tires while watching the gears in the differential, make sure there are no teeth missing or broken off, if it all looks good and you can't see any damaged gear teeth then bolt it back up and make sure you replace the cover gasket, I use 85w140 royal purple and yes it does have the limited slip additive in it, worst case senario is that you need new gears and I did the 8.8 swap for about 500 bucks so it was def. worth it

Most 8.8's don't use a gasket. Mine didn't have one from the factory and since it was dry after 100k I don't plan on putting one on it.

 

[Sasquatch_Ryda]

Yea, RTV silicone is a much better sealant than any gasket.

 

[pacodiablo]

75W140 or 80W90 will work fine.

Use RTV Ultra Black silicone. Make sure it has the "Ultra" part printed on the tube.

 

[Defective]

I ended up calling it all good after looking at it pretty darn close. I put Valvoline 80w90w with whatever brand additive Schucks had on there shelf. I couldn't bring myself to spend that much on Royal Purple right now, 15.99 a quart. I already had some Valvolene on my shelf at home so I used it also to save some money because I didn't think this was going to solve my problem.

Anyway, after putting it back together the problem is still there. I'm back to thinking it's something in the front end. The thing is I've replaced almost everything up there and don't know what could be making this sound/rubbing feeling. It sounds like a "big wheel" bike. It does this with hubs unlocked or locked. Could it be the hubs themselves? What do bad hubs feel like?

 

[Defective]

And I did actually find two more things wrong up front last night. The lower passenger side ball joint is a little loose and the steering gear has play in it to the point I can shake the tires back and forth and make it make a thunking noise. The steering wheel turns almost instantly though when moving the tires. Rotating the tires yielded no funny noises or rubbing.

 

[pacodiablo]

Check the fluid level/condition in the front diff.

 

[Defective]

The fluid in the front is brand new Royal Purple 75 90w. No extra additive.

The noise happens with hubs unlocked and the front diff is not turning.





Can I put the tire on without the hubs and drive to see if they are causing the noise?

 

[Bent Bolt]

Is the noise there driving straight or turning corners or both ??

 

[Defective]

Both, I'm actually starting to think it's my driveshaft carrier bearing and that's why it's difficult to determine front or rear.

 

[Bent Bolt]

Very possible. A quick rundown on noises from the rear :

Noise only happens on turns : could be side and/or spider gears, limited slip clutches.
Noise at tire speed : axle bearings, brakes, carrier bearings, tires.

Driveline noises ( kinda at road speed but faster )
u-joints ( squeek-squeek or vibration or bang )
carrier bearing ( steady drone,may or may not be effected by throttle )
pinion bearings ( will be effected by throttle )
crown and pinion gears ( drone at a particulair speed or all the time moving, or steady chunk-chunk noise from missing/damaged teeth)

There are more but this is a basic list. Your results may vary.