rear end fluid change

[alpinekid]

Hi folks,
I bought this bus awhile ago and I’m still working on the complete preventive maintenance review and filter/fluid change. So far I’ve seen nothing that give me much concern.

This week it has been the rear end that has had my attention. After getting a big enough breaker bar I got the filler plug out and I removed to rear cover. There was no drain plug so this was the only way to change the fluid.

There was about ¾ gal of really black fluid in it. No idea if it was synthetic or natural oil, it was real black and flowed easily. The cover was coated with a thick layer of a sticky grease like substance. No sign any metal particles but it did take quite a bit of work to clean that stuff off. After thinking about it for while, maybe it was a protective coating as a by-product of a synthetic oil. The reason I think that is I did not see any rust on the inside but after just a short while spots of surface rust appear on the inside clean metal. I quickly applied fresh oil to stop that.

I’ve cleaned and painted the outside surface and I’ve got a replacement gasket and some black gasket goop ready to replace the cover; and a few questions:

1) is there anything I should be checking while I have the cover off?

2) what is a good fluid to put back in and why is it good.

3) what are the trade-offs?

I’ve got some fresh but really old 90-140 gear lube but I see a lot of folks going with 85-90. any thoughts
I’ve included some images for your edification. I’ve heard pictures are always good
Thanks
Al

 

[Booyah45828]

Looks to be a dana 60 axle.

I've never had luck with gaskets and stamped steel differential covers. I usually use gear oil rtv from permatex, and haven't had issues with doing that.

Be careful on the paint you use inside. The additives in the gear oil might eat/soften the paint, and cause it to fall off. I'd skip the paint altogether if I were you.

As far as fluid goes, you can use any rear axle lubricant. Originally I think they spec'd 90w, so you can go with a conventional 80w90 if you'd like, or you can bump up to a synthetic 75w90 or 75w140 if you are heavily loaded. Just use a good name brand fluid and go with it.

 

[alpinekid]

Thanks for the info, I'm not painting the inside surface. I only cleaned up so it wouldnt make a mess on the bench.

 

[Native-SKO]

I just changed the differential oil in our bus ... 4 gallons. It calls for 17 quarts of organic 80W90 gear oil. I suppose I did not drain it all out since it was cold so there might have been a quart left inside the axles. I will say that it is now much less noisy.

 

[alpinekid]

thanks, I dont feel so bad, my diff was 3/4 gal. It is only a dana 60.

I can't find a manual for this bus so I'm just guessing on what kind of replacement oil. The stuff that was in there was as black as coal but still flowed ok.
I have an old jug of valvoline 85w-140, so I'm thinking of just using that.

 

[Native-SKO]

thanks, I dont feel so bad, my diff was 3/4 gal. It is only a dana 60.

I can't find a manual for this bus so I'm just guessing on what kind of replacement oil. The stuff that was in there was as black as coal but still flowed ok.
I have an old jug of valvoline 85w-140, so I'm thinking of just using that.

Call or visit your dealer. They will have it spec'd in their parts breakout for the rear-end. While you are there, you could also get the volume as well as the type and volumes of all fluids.


They will need your VIN.

 

[Kubla]

The fill plug is on the side of the diff, you fill it until it starts coming back out

 

[alpinekid]

Thanks for all your input,

I'm just closes with what I did.
It looks like it really is a dana 60 - 4.10 axle, there is a 60 cast into one corner of the casting.
I've finished up with the fluid change in the rear end.
I picked up a new gasket from napa, on one side of the package it says FEL-PRO; pn RDS 6095-1 ; on the other side it says federal-mogul
I put a continuous small bead of permatex ultra black maximum oil resistance gasket maker on both side and tighten the bolts to 35ft-lbs.

I refiled with valvoline 85w-130, I had most of a gallon left from a project years ago. It took all I had left.

On to the next step:

Am I correct is assuming that it is the fluid in the differential that will flow to the rear bearing in the hub and lub them? or do I need to pull the axles and grease the bearings?

 

[Ronnie-SKO]

On a dana 60 or 80 the wheel bearings are lubed by the differential lube, so no need to pack them seperately.

 

[alpinekid]

thanks for the info. I was hoping that was the answer.