Synthetic Rear Differential Fluid

[Jetpilot]

I am going to be changing my rear differential fluid and want to put in synthetic. I have the limited slip differential and have seen some posts where guys have had good luck with the synthetics and no modifier... I like synthetic fluid, and really would like not messing with getting the modifier just right. I think the most favorable brand was Valvoline. Also wanting to go with 75W-140. What weight fluid is everyone using and are you satisfied with your choice?

Please let me know what is working and/or not working for you.

Thanks,

Doug S.

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2001. 5 2500 SLT 4X4 QC SWB Sport, Auto, 3. 54 LS, Trailer Tow, Camper Special, DD2's, PE-Comp, DTT TC & VB, VDO Boost & Pyro gauges on A Pillar, K&N.

[This message has been edited by Jetpilot (edited 06-01-2001). ]

 

[Gary C]

I just went to Redline and used the modifier, cheap insurance.

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2001. 5 2500 QuadCab SLT, Auto, 3. 54 Anti-Spin Axle, 4X2, SWB, White/Tan, Stockland Camper, Interior kit, Debadged, Custom CUMMINS Logo Sticker, Front Spoiler, Sport Tail Lenses, Valentine One, SPA Gauges Pillar Mount, Magtech transmission Pan and Rearend Cover, HX 40 and 16cm turbo, DD2's, 4 inch exhaust and down pipe with two muffles from DD, Diesel Dynamics' New Ultimate Power Module, Psychotty Air Box, DDT 91 TQ and VB, DTT Smart Controller, transmission Blueprinted by DD, 450+ HP/930+ftlb.
www.ProwlerOnline.com
View my Cummins Sticker

 

[Dieselnerd]

I'm using Amsoil 75-140, series 2000. I found it works best with one bottle of modifier even though they claim it doesn't need it. Without one bottle I would get chatter in tight turns.

 

[Sled Puller]

I have sold a lot of Amsoil Series 2000 75w-90 and 75W-140 to Ford and Dodge guys with LSD.

As long as they do tight figure 8's after the change, no modifier is needed. The ones who forgot, called and complained, then they went out and did them, problem solved.
Mine also.
I would try it without, and add a little modifier at a time if needed.
Gene

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CPFF's Dowell Pin Jig Available in GLTDR Region! 1997 Cummins Dodge 4x4 "One Piece At A Time" Bombed & Amsoiled. Amsoil Executive Direct Jobber, Member of: NRA Business Alliance, GLTDR, WANTED: Wrecked Dodges.
www.awdist.com

 

[LSMITH]

I have the Mobil 1 75-90 with no modifier, but need to add a little. It chatters a little in tight turns under power even though it said it has the modifier. I did do the figure eights. I do very little towing so I did not use the 75-140.

 

[Pete Peterson]

With the Amsoil series 2000 75/140 as advertised it works without the modifier at least for me. The other synthetics require the modifier I believe. Don't forget to put on your Mag-hytech cover while your under there!! !!! Pete

 

[drawson]

I am running AmsOil ser 2000 75W-90 gear lube with a LSD and have not had to add any additive. All I did is go to a church parking lot and turn 10-15 tight 8s and no problems at all with out that stinky additive.

 

[tom sweeney]

i'm using mobil 1 75-90 with NO friction modifier... i haven't discoverd any chattering yet!!! i just came back from a 6500mi. trip to the west coast towing my 26ft. 5'er with no problems at all.

HOWEVER... . if i can find enough valvoline or mobil 1 75-140 i will probably change to that weight just for the peace-of -mind... .

anyway,good luck with the change-over... . tom

 

[John]

I've been using Amsoil Series 2000 75W-90 in both differentials. I had to add 1. 5 oz. of Mopar friction modifier (. 5 oz. at a time) to tune my OE LSD clutch characteristics.

 

[MikeR]

I also have Amzoil 2000 75/90 in both axles. No modifier needed in mine,it works perfect.



Since synthetics have way different characteristics than fossil oil,you don't need to go with 85/140.