Rear end fluid recommendations...

[Idually]

I don't want want to start a "this is better than that" thread, but What is the appropriate "Gear oil" (Weight and such), for the D71 with 3. 07 gears? I would like to preserve a fairly endangered gear set, that is in good condition(from what I can tell), so any recommendations are welcome. What are you guys using? James???

Synth or no?

Fairly certain it's an open Diff, but not 100%.

I just took a peek at the fluid in the rear of "Redram" and it is BAD. VERY bad. Almost looks like chocolate milk... Ewww.. . :--)



I will be draining it immediately as well as checking the rear bearings, etc...



Again... Thanks!

 

[Philip]

I use regular 75/90 in my D71. Synth is good oil. I use it in my transfer case. But it will go threw old seals that will hold 75/90 in. I don't like cleaning up after a synth mess on brake drums from a leaking seal.

 

[btoscano]

When I had a set of 3. 07's the first time I changed the gear oil my fingers bled from the metal shavings I scooped out of the housing and the fluid was black. I refilled it with Redline 80w-140 synthetic. Drove 10Kmi and did it again. Did I mention I got a closeout deal on the Redline? The current owner has put more than 2,000 hours of hard work (in about 2 years) on the truck hauling junk - always dragging around a double axle trailer. He had the legendary 727 replaced because it self-destructed, has replaced 2 driveshaft yokes, and some u-joints, but the 3. 07's live on..... Maybe its because of the 80w-140 weight, maybe because of Redline, or maybe that particular set of 3. 07's was made with kryptonite. I find that 90 weight is black when I drain it, but the 140 weight stays light. It may be related my long distance freeway driving, some of which is across the desert.

 

[bgilbert]

I prefer dino gear oil 75-90 or 80-90wt. I like NAPA brand 75-80-90wt. Pass on the synthetic.

 

[DKasper]

I use Royal Purple from NAPA -- any good quality lube will do the trick, but the most important thing is to change it regularly. Some people tend to put in an expensive synthetic and then think things are good forever. What they forget is that the condensation in there is what makes the diff oil look milky, and the only way to get rid of that is to change it.



I change mine every 12-18 months. I also used JB Weld to attach a nice big magnet to the bottom of the cover -- the stock one was gone for some reason.



Regular changes will ensure the best possible environment for your hard-to-find gears!





Dave

 

[btoscano]

DKasper,



Good point! I change my fluid a minimum of every 2 years