Differential Fluid Questions

[WAckerman]

My truck is up for its 30k mile service and I'm wanting to do my own differential service, however I do not own the Factory Service manual. I have looked around here trying to figure out what fluid I need, but I'm a little confused. I've heard that the Morpar fluid is very expensive, so I would like to know what options I have.

My questions are as follows:

1) Is the 75w-90 the correct fluid? (I don't tow heavy or often)

2) my truck is a 2005 3500 (see sig), does it have the O-ring covers or do I need to be prepared for sealing the covers w/ RTV?

3) What are the torque specs for the bolts on the cover?

4) should I go with the mopar fluid or get another brand? I looked at the Amsoil site and they listed several different types of fluid. Long gear life vs severe gear... what should I do? I've read that the fiction modifier needs to be added, does the factory and Amsoil fluid have the additive?



I'm sorry for all the questions, and thanks for your help.

 

[jray]

The rear housing on a 11. 5 AA rearend uses a reuseable gasket. You don't need a friction modifier with this rearend. I use Amsoil synthetic in my 11. 5 but it's the thicker stuff 90-140 due to towing. You should be fine with 75-90w. By the way I really like this Amsoil in the rearend. I recently changed the rearend fluid again at 67,000 and it came out looking like new with little if any particulate matter at the bottom of the housing.

 

[ScottLewis]

I used Royal Purple in both the front and rear diffs on my truck, 75-90 in front, 75-140 in rear (I tow fairly heavy and often). Both oils cost $12. 95/Qt. ; 4 qts for the stock rear and about 2 1/2 for the front. Dealer cost would have been about $16 for the 75-90. and $25 for the 140. FSM says 30ft/lbs on cover bolts but I've heard of guys snapping them off at that torque. The factory used red locktite on the bolts so they come out pretty tough. Although Royal Purple has a LS additive in it, I added a tube to the rear anyway as insurance. Some say you should, others say you don't need it. Your call.



Dan

 

[WAckerman]

Thanks for the quick response guys. I'm confused because the dealer here is saying that the Mopar "DR" fluid is a dealer only item and it has the friction modifier in it... and that the DR is the mother of all fluids...



I've had such bad luck with my dealer, that I just want to write them all off as not knowing anything, which they may not! :-laf

 

[jray]

Check this link for further info.

https://www.turbodieselregister.com...-2003-2007/106267-american-axle-new-info.html Actually old info.



I don't blame you for wanting to avoid the dealer. I do however use factory brake pads on the 3g because they last.

 

[magothy1]

Run a search on differential fluid, there's some great advice in there. Did mine today for the first time, it's a pretty easy do it yourself thing.

 

[rbattelle]

I've been running Valvoline Synpower 75w-90 since the first change at 15k. On my next change (in about 2k miles) I'm going to try out some Kendall Elite 75w-90 (which I've been told is identical to the Valvoline but in a different bottle).

Always a GL-5 synthetic. Never any friction modifier (in my opinion, Torsen-style differentials don't require any).

Ryan

 

[Cal Brewin]

I use Redline, a 50/50 mix of the 75w90, and 75w90ns. Has worked great for me.



Here is a link if you want to download a factory service manual. I did and it is a full function clickable copy. Go to the left hand column and page down, you can't miss it Includes all diesel sections...



Tom



"The Premiere website for Hemi Ram and Hemi SUVs. "

 

[MChildress]

Royal Purple 75-90 last 25,000 miles with no problems.

 

[WAckerman]

Thanks guys! Ryan, do you get any gear chatter w/o the friction modifier? I've read some guys are getting it and some aren't. I guess its not too big a deal to put it in if I were to get the chatter.



Tom thats awesome! I had lost the link to that and I had been looking for it for a while! Thanks!



Jray, that link is a good one. I didn't think to search for "American Axles" i search "differential fluid" and got a million hits... thanks for the help. I know everyone get tired of answering the questions. Maybe we could get a sticky in the First Time Cummins Owners that we could post acceptable fluids? just a thought.

 

[rbattelle]

I don't get any chatter. I still don't understand what the chatter that some people hear is - there's no clutch packs back there!

Ryan

 

[DZLFREK]

diff fluid

WAckerman,



The fluid change is quite easy. I used Royal Purple 75w-90 in my truck with the MOPAR friction modifier. Get some "Brake Clean" and use it to clean the inside of the diff's when you have them off. I don't tow yet (saving for the boat) but the weight of oil works best for me at this time. Take your time and all should go well. Feel free to PM me if you have any questions about the oil change.

 

[WAckerman]

Thanks for the offer Dzlfrek. I'm going to try tp pick up the lube next week sometime and then find the time to tear it apart. I'll let ya know if i have any problems.

 

[JDerrick]

I used Lubrication Engineers non-synthetic gear lube front and rear in my

99'. I ran the same oil in it for over 100k miles. The front showed no wear or discoloration. The rear had just started to turn slightly darker than when it was fresh, ( I checked it 2 two weeks before I traded in the truck 149k). My 99' saw a VERY significant off road use in the fire rescue industry. I am VERY satisfied with LE products ( thank you Joe Donnelly ). I WILL have LE products in my 2006 as soon as the Mag Hytec diff covers arrive and get installed.



Just my $0. 2

 

[HEMI®Dart]

Overkill...?

Anybody add a Pump & Cooler for their rear diff fluid?







Tilton Transmission/Differential Oil Cooler Pumps - summitracing.com

 

[rbattelle]

Anybody add a Pump & Cooler for their rear diff fluid?







Tilton Transmission/Differential Oil Cooler Pumps - summitracing.com

Wow, that's hard core! Let us know if you decide to do it.

(Overkill? I don't know the meaning of that word. )

Ryan

 

[JDerrick]

HEMI®Dart Anybody add a Pump & Cooler for their rear diff fluid?







Tilton Transmission/Differential Oil Cooler Pumps - summitracing.com











sounds cool ... ... ... ... ... ... ... ...