Diff fluid change

beastofwar · Sep 1, 2009

So I'm going to do the 60k service myself, part of which is changing the diff fluid. How difficult is this? Though I'm moderately competent, I'm far from an expert. One tutorial thing I saw online someplace said to spray it out with brake cleaner and let it dry before reassembling and refilling with lube :bugeyed: That seems sketchy to me.

Any advice/tips/brief instructions would be very much welcomed.

TIA

MWeed · Sep 1, 2009

Use brake cleaner and spray liberally. This will help flush out the old lube and clean things up considerably. It'll dry in just a few seconds and leave no residue. Carb cleaner spray also works. If you have limited slip in the rear end, be sure to get a tube for the refill. Use RTV for the diff cover sealer, and use the type labeled for gear oil use. Make sure the cover flange is flat prior to re-install. Same for the front, other than the limited slip additive.

beastofwar · Sep 1, 2009

Thanks.
:twisted:
Seems like it should be pretty straightforward.

qwassy111 · Sep 1, 2009

MWeed said:
Use brake cleaner and spray liberally. This will help flush out the old lube and clean things up considerably. It'll dry in just a few seconds and leave no residue. Carb cleaner spray also works. If you have limited slip in the rear end, be sure to get a tube for the refill. Use RTV for the diff cover sealer, and use the type labeled for gear oil use. Make sure the cover flange is flat prior to re-install. Same for the front, other than the limited slip additive.

Doing the same on my Gen 1 ('02) 4.7 soon. Mike covered it! Suggest gettin Scotch Pads to remove any residual RTV or gasket that might remain on the mating surface. Also, make sure you get the brake/parts cleaner on the mating service and that the surfaces are completely clean and dry (no old gasket/RTV remaining) otherwise the case may leak? may or may not, just throwing my 2c in. Good luck! Let me know if it's as easy to do as I'm hoping.

Thanks to all the great help, info and people here on the DOC, the truck hasn't had to go in for service nearly as much? I guess the $ I'm saving could go towards membership <cough>

greendurango · Sep 2, 2009

I've also heard to use no gasket just the RTV Permatex. I believe black is the best?

Zen · Sep 2, 2009

My D is just over 70k now and I'm not sure if the diff fluids were ever changed, been thinking of doing this myself lately, any and all info is doubly appreciated!

IndyDurango · Sep 2, 2009

Ask a question like that? now YOU BOTH get the noob treatment?

:wall: :roll: :cheesy: :naughty:

IndyD

Zen · Sep 2, 2009

I figured I'd get that from you Indy, I'll do some research of my own and come back with any further questions.

This may also be a dumb question but here goes: How can I tell whether or not I have a LSD, I don't think I have one but I'm not entirely sure. :?

MWeed · Sep 2, 2009

Look at the left end of the rear axle tube right behind the backing plate. If you have the limited slip there'll be a light colored stripe painted around the tube and some words to that effect on the tube. Or you can look through the open glovebox at the inside of the firewall and it should tell you on the buildsheet stuck on there.

Zen · Sep 2, 2009

Thanks! I'm pretty sure '03 SLT models never came stock with the LSD, I was thinking of getting that when I go for the bigger gears sometime in the future.

FSTDANGO3 · Sep 2, 2009

There was an optional limited slip in 03
Steve
DOC Pres

tomk · Sep 2, 2009

yes, my '03 had LSD from the factory:
DJDS - 205MM Front Axle
DMDS - 3.55 Axle Ratio
DRAP - Corporate 8.25 Rear Axle
DSA - Anti-Spin Differential Rear Axle

Friction modifier doesn't hurt, so if in doubt just add it.

qwassy111 · Sep 2, 2009

Zen said:
Thanks! I'm pretty sure '03 SLT models never came stock with the LSD, I was thinking of getting that when I go for the bigger gears sometime in the future.

figured I'd beat mike to the punch, but from what I hear you'll get more benefit from a "Locker" than the limited slip. The detroit locker is probably overkill but there was another company out there that offers a quiter version. Check the archives under me or mweed for lockers.

beastofwar · Sep 2, 2009

IndyDurango said:
Ask a question like that? now YOU BOTH get the noob treatment?

:wall: :roll: :cheesy: :naughty:

IndyD

Yes I do? But evidentally not the skills to find the right keywords I guess. I just find a bunch of stuff about what weight fluid to put in a Gen 1? :doh:

MWeed · Sep 2, 2009

Try Detroit Locker or PowerTrax

beastofwar · Sep 15, 2009

Well it seemed to go well. Except I was expecting to fill it till the level came up to the fill hole (based on experience with FWD gear oil changes and some stuff I read here) Haynes said to use 2.25-2.5 qts depending on the diff (Still not sure which one I have.) Since I was expecting the level to reach the fill hole I didn't really pay attention to how much was going in so all 3 qts that I bought are now in there, yet the level isn't even close to the fill hole. Did I overfill? Or is haynes wrong in which case; did I underfill? :wall:

Interestingly though the manual and haynes both say 75w140 the dealer says 75w90, I bought it from them, which is expensive ($20 per qt).

JasonW · Sep 15, 2009

Interesting. It should only hold 2.25 qts.

Weights should be 75W-90 in front and 75W-140 in rear.

qwassy111 · Sep 15, 2009

JasonW said:
Interesting. It should only hold 2.25 qts.

Weights should be 75W-90 in front and 75W-140 in rear.

That's interesting, wonder why the excessive fill unless according to the chart you have one of those big daddy's back there. I have the 9.25 rear so should only take about 2L,
I picked up 75/90 for the rear as per the owner's manual or haynes can't remember which. oh well.

JasonW · Sep 15, 2009

That table above is from my 2005 Ram FSM. However, Chrysler may recommend a thinner lube for the Gen2 D's. On a side note, the FSM for my wife's 2000 D shows recommended lube of 75W-90, so I think you're ok.

beastofwar · Sep 16, 2009

Lube in handbook is 75w140. Dealer has been using and told me to use 75w90.

There are no leaks that I can see, so I think I'll get a suction pump and pull some of the lube out. Guess these guys don't do the fill till it's level thing any more.

What's a simple way to tell the difference between an 8.5 and a 9.25 rear end?

Diff fluid change

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MWeed

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FSTDANGO3

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MWeed

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