Differential Service

klutchdust wrote:

ron.dittmer wrote:
I wonder how a shop sees metal shavings in the diff fluid when checking. Maybe they sucked some fluid out from near the bottom with something like THIS SUCTION GUN. I use one for adding/filling differential and manual transmission fluids.

Good question. Maybe a flexible magnet into the fluid. Metal shavings are common in those types of gear assembles. And when they say shavings think the size of ground pepper or even smaller, more like metal chips/flakes, not what you see when you drill holes in steel.

I would describe metal particles in vehicle differentials and transmissions as "black and gray mud" that forms at the bottom.

I have seen in new lawn equipment, cheap machinery by comparison, a metallic glistening in the first engine oil change (during the break-in period). That does not describe diff and trans fluids in a vehicle.

ron.dittmer wrote:
I wonder how a shop sees metal shavings in the diff fluid when checking. Maybe they sucked some fluid out from near the bottom with something like THIS SUCTION GUN. I use one for adding/filling differential and manual transmission fluids.

Good question. Maybe a flexible magnet into the fluid. Metal shavings are common in those types of gear assembles. And when they say shavings think the size of ground pepper or even smaller, more like metal chips/flakes, not what you see when you drill holes in steel.

I wonder how a shop sees metal shavings in the diff fluid when checking. Maybe they sucked some fluid out from near the bottom with something like THIS SUCTION GUN. I use one for adding/filling differential and manual transmission fluids.

Grit dog wrote:
^Exactly. And your explanation may help the OP understand that.
Maybe I wasn’t clear, but I don’t consider a broken spring locator pin an alignment issue, but rather a parts failure. I consider alignment something that is adjustable.

Thanks for the feedback.

Thanks for the update!
Leak at hub explains fluid loss.

Picked up the RV today. There was no rear axle alignment in the description of service. They sent it out for a regular alignment as they don’t do those in the shop. Didn’t get the exact alignment specs but they set the toe in from zero. Between 1/16th and 1/8”

They just checked the alignment of the front to the rear tires and it was spot on. The differential service appeared to be the result of observing bad hub oil during the rear brake job. It was just serviced no other issues.

^Exactly. And your explanation may help the OP understand that.
Maybe I wasn’t clear, but I don’t consider a broken spring locator pin an alignment issue, but rather a parts failure. I consider alignment something that is adjustable.

Grit dog wrote:

EMD360 wrote:
Recommended differential service is between 50,000 and 60,000 miles. So it was time. They just replaced the gasket and the fluid. Because it was just service the warranty does not cover it. Didn’t hurt to ask. I still don’t have the RV though because they were not happy with the alignment so sending it back for a rear axle alignment. These look like they are relatively uncommon. But if the steering wheel is off center or there is pull one way or the other I guess it’s possible the rear axle can be adjusted. Can’t find much on it on Google. So the shop that does alignment for them can’t get to it until next week. It’s drivable they say but I didn’t want to experience a problem after all the work I’ve had done so I won’t get it until 2022!

Fwiw, unless there are some extenuating circumstances not mentioned, it is virtually impossible to knock the rear axle of a solid axle vehicle out of “alignment” and it is 1000% not adjustable. If for some reason there is a gross misalignment or bent axle, it is a mechanic shop or body shop job.

Or in other words, you’re likely being sold a bill of goods on the rear alignment. Beware.

Leaf springs have a center pin that protrudes out and a saddle may sit on and be centered by that pin.The axle sits on that saddle and is held together by the leaf spring u bolts. If the pin fails the axle can move. Occasionally you will see bob tail or pick up trucks doing the doggy walk down the road, favoring one side or the other.

FWIW fact: I performed wheel alignments on semi trailers and the front axle was 1/4 inch longer in measurement from the king pin on the drivers side and the rear was adjusted to be exactly the same distance from the front axle. This was to keep the trailer axles favoring the crest of the road. Often a trailer came in for wheel alignment as the driver noticed the trailer "dog tracking" A broken center pin was the first item we checked.

EMD360 wrote:
Recommended differential service is between 50,000 and 60,000 miles. So it was time. They just replaced the gasket and the fluid. Because it was just service the warranty does not cover it. Didn’t hurt to ask. I still don’t have the RV though because they were not happy with the alignment so sending it back for a rear axle alignment. These look like they are relatively uncommon. But if the steering wheel is off center or there is pull one way or the other I guess it’s possible the rear axle can be adjusted. Can’t find much on it on Google. So the shop that does alignment for them can’t get to it until next week. It’s drivable they say but I didn’t want to experience a problem after all the work I’ve had done so I won’t get it until 2022!

Fwiw, unless there are some extenuating circumstances not mentioned, it is virtually impossible to knock the rear axle of a solid axle vehicle out of “alignment” and it is 1000% not adjustable. If for some reason there is a gross misalignment or bent axle, it is a mechanic shop or body shop job.

Or in other words, you’re likely being sold a bill of goods on the rear alignment. Beware.

larry barnhart wrote:
We have an 05 3500 chev dually bought new and now has 113K miles on the truck. I have changed the rear fluid 13 times because it was an easy job for me to do. Kinda overkilled all maintenance but the truck feels and drives like new.

chevman

“kinda” overkill is not a strong enough descriptor. More than 3x since new would be the start of more than necessary, imo.
If you’re changing, say, 50k mile fluids at <10k miles, are you changing engine oil at like 2000 miles?