I have a 1994 f-150, 302, 5spd tranny. I believe it has the 8.8 ford rear end and a dana 44 front. I was just wondering what weight fluid and how much went into them. I plan on changing to synthetic and hope to do this tonight at least to the rear end.

Thanks,
Matt

 

What's the axle code on the door sticker?

Jason

 

Axle code is 19.

 

That's an 8.8" rear end, then, with 3.55 open gears (no LS). As for what weight, I've never messed with a rear end before. You don't need the friction modifier, though for the LS you don't have.

Jason

 

Does anyone know for sure what i need? All I am finding in the owners manual are parts numbers. Are you sure its 3.55's i thought i figured out it was 3.73's or something close to that before.

 

It should have came with 80-90W in the diff but if i was going to drain and refill I would put 75-140W in it. That is the new updated fluid that ford uses in all their new vehicles it last longeer and holds up better. But You cant go wrong by putting 80-90W back in it

 

Wow my memory sux it does have 3.55's for gears. I'm gonna go see if i can find soem fluid and get it changed before dark.

Thanks

 

75w140 seems like overkill man... I used redline synthetic 75w90 in mine, works flawlessly

 

Will 75-140 hurt anything? I already picked some up.

 

Shouldn't hurt anything, but it is a good rule of thumb to keep the difference between the high and low thresholds as minimal as possible; ie, 140-75 = 65 OR 90-75 = 15

At least that's the way it is with motor oil and gear oil has similar properties...

 

Where did you hear that, Chris?

A 75w90 is a 75-weight oil with modifiers to make it act like a 90-weight oil at higher temperatures. A 75w140 is a 75-weight with modifiers to make it act like 140-weight at higher temps. So it all depends on what your application is, not on some rule of thumb.

Jason

 

Andy sent me a link to an article written by a guy who was employed for an oil manufacturing company and he explained how motor oil works and what the rating system means, and how to choose different oils for different applications. One of the things I remembered was that he said to try to choose an oil with the smallest difference between temperature ratings. I'll see if I can dig up the link later.

 

75-140W is what i use in my 8.8 limited slip in my 86 mustang GT i work at a ford dealership and thats what we use for most applications there

 

It all depends on your operating environment. I work in Fairbanks AK sometimes through the winter. The 75-140 synthetic works great from -50F to +100F which can be the temp difference there from Jan to July. In a more moderate climate, the 80-90 is probably OK.