Had a rear pinion seal replaced on my 2000 350 RWD, Dana differential at local Ford dealer, I noticed that they replaced fluid with 75/140 . Asked them about the book shows to use 75/90, reply was that Ford memo update that they discontinued the 75/90 and said to use the 75/140, If this is the case would this create any problems?

 

That is correct they put the right fluid in.no problems
do you have a LS unit in the diff hope they put the friction modifier in.
Rich

 

Dont know if they put the friction modifier in or not , I will have to try some slow turning in a parking lot and see if theres any popping in the rear end.

 

You did say Dana rear axle? As in the standard Dana 80 axle that comes on all duallies? If so, the correct fluid is the 75w90 unless Ford just changed their mind again.

The following is out of the August 2006 version of the Ford workshop manual.

Code:
--------------------------------------------------------------------------------

F-Super Duty 250-550/Excursion Workshop Manual SECTION 205-02A: Rear Drive Axle/Differential — Dana 80 SPECIFICATIONS ................... Procedure revision date: 01/06/2003 -------------------------------------------------------------------------------- General Specifications Item Specification Lubricants and Sealants SAE 75W-90 Synthetic Gear Lubricant XY-75W90-GLS WSP-M2C197-A Additive Friction Modifier XL-3 EST-M2C118-A Premium Long-Life Grease XG-1-C or -K ESA-M1C75-B Silicone Rubber F7AZ-19554-CA ESB-M4G92-A Threadlock® and Sealer TA-25 WSK-M2G351-A5

--------------------------------------------------------------------------------


Glancing at the workshop manual for a 2007 Dana 80, it says:
Code:
--------------------------------------------------------------------------------

SPECIFICATIONS Procedure revision date: 05/11/2006 SAE 75W-90 Premium Synthetic Transaxle Lubricant XT-75W90-QGT

--------------------------------------------------------------------------------

I also found a very current Motorcraft web page that lists 75w90 for Dana 80 axles, but regretably I can't find it again.

 

you better ask to see the memo.
Harald may be right
and I wrong ,(that never happens).
Harald the sheet i just looked at published 9/06 rev3.2 (notice the rev #)
They have changed it how many times now?????
My sheet says the same thing as Harald
If this is a DANA 80
Rich
Sorry for the confusion

 

Thats what the local ford dealer said the latest meno they got said to use the 75/140. So today I googled Dana and got there phone number for there tec support and talked to them , They said the 75/140 would be find, his only concern was because I live in northern Minesota with cold winter temps it could be stiffer in the winter but went on to say it still would be ok , on the other hand better in the summer temps.

 

Forgot it is a Dana 80, so who do you believe Ford or Dana?

 

I would go back to the dealer that did the work and get their memo in writing.
So if and I say if you have any further problems with the diff.
They did the work ,they put that fluid in.
Basically a paper trail for yourself
Rich

 

IMO...I would not be worried about the gears so much...but the added pressure of the thicker oil inside the axle. Could cause seals to blow out...and cost $$$ for repairs. Especially if not noticed right away...and running with low amount of gear oil....then could cause the gears to overheat...and break down.

Take back to dealer...and either they show you the "MEMO" or have them change the gear oil to spec.

I suspect that the dealer just got lazy...and went the 75w140 route.

SIDE NOTE: I recently asked the dealer for a quote on changing the FRONT D60 on my SD...and they also told me the 75w140 route. I said the Owner's manual version 5...says SAE90??? What gives??? All versions say SAE90...and has never been changed to reflect the so called new use of the 75w140 gear oil. OBTW...The 75w140 costs more than the SAE90...so guess what they want to use!?!?

biz

 

The lower number (75) is what determines the viscosity at lower temps. That is THE purpose of multi viscosity lubricants. The upper number only applies under hotter conditions. The 75-140 will react exactly like the 75-90 at low temperatures. So if you start out in the morning in the winter and pull 9,000 pounds uphill for 4 hours the fluid will protect you better on the whole drive. But if I lived up there I would see if you can find something like a 60-140. Probably doesn’t exist. Do a lot of differentials up there burn out? If not then you can assume the fluids in general use are quite adequate. And the comment about the price may be wrong. The dealership may get bulk pricing that could be anywhere on the spectrum. 75-90 differential oil