i was wondering what you might recomend as the best oil for my rear diff. I was thinking about a fully syn 75w140 because of the cold climate i live in here or should i just stick to the 75w90 or even 80w90?

Cold man

 

Ford says 75W140.

 

It needs to be full synthetic 75W-140 for the Sterling and Dually Dana 80. I recommend Royal Purple from O'Rielley's. If you have a Dana 135 F550, then it would be 80W-90.

 

Second royal purple, I was told once, that its the only oil, you can add top off with any other oil in a pinch, and not have to worry about it. It was from a guy named Steve, at Differential Engineering, based out of florida. Thats all they do, is manufacture differentials, from factory rebuilds, to custom badass stuff for people doing truck pulls. He built mine for me, and hes got great customer service

 

I put 75W90 Royal Purple in my dana 80 .

 

I've experienced a significant fuel economy improvement using Lubrication Engineers 607. I have a Dana 61 with a limited slip in my F250, and after changing to LE607 my mileage went from 8.5 to slightly over 10mpg. Differentials are a real high friction area, at least older designs are.

Good luck!

 

Probably a silly question but how do I tell which rear end is in my 99 F350 CC 4x4 manf. date of 5/98 ?
thanks
Scott

 

The more important question is, is it SRW or DRW. SRW should be a sterling 10.5, DRW should be a dana 80.

 

rebchevy hit the nail on the head for the rears. The front axle is a dana 50.

 

Has anyone ran Schaeffers stuff. 75w-140. I am getting ready to install a Detroit Tru-trak and just wondered what people's thought were. I have had great success with their oil and trans oil.

 

only problem with Schaeffers is you have to buy a 5 gallon pail (unless they changed the packaging since last year). got Royal Purple in mine. Also think about putting on a better differential cover like a Mag Hytec

 

For us differental dummies, can you give us a run down of what you are talking about? I have a 2000 F250. Where can I find what type of diff I have? I am going to replace the rusting diff cover and want to put the best fluid in I can find. Also does anyone have the instructions typed up somewhere on exactly how to change the diff cover and fluid?

Thanks in advance....

Steve

 

I assume that you have a manual tranny as the Lubrication Engineers 607 Lube that you tout is not recommended for auto trans.
gsull

 

Pretty straightforward really just unbolt drain, rebolt new to torque specification and fill.
Guzzles maintanance page would help you alot, I could`nt post the link for some reason but it`s easy enough to find. The most common rear on our single rear wheel trucks is the sterling 10.5 (ring gear) with a 3.73 (gear set)(ratio).Limited slip was optional. You should have a tag on the rearend housing that tells what you have. You can look up the codes that are on the tag with the search tools here.

 

http://guzzle.rbmicro.com/ for guzzles write ups. for what diff. you got look on the drvers door post sticker and go here https://www.ford-trucks.com/forums/4...lder_____.html for what the codes mean if your truck does not have the code on the door,mine does not have them, look on the tags on your diff.