hey guys i just bought a 95 xlt 4wd and i'm trying to change the front diff fluid.
1. What kind of fluid should i use? i looked it up at partsource and it says to use atf? but i've never heard of a diff that takes atf.
2. it there and way to drain the fluid with out removing the whole diff assembly?
any info/tips would be great, thanks a bunch
I originally checked out this thread in hopes of a real answer but now I'd like to share what I have found. I am a one man repair shop and use alldatapro which lists the spec for the front dif fluid but no actual viscosity or anything useful. This was for my 1996 exploder xlt. Just bought it two months ago with 135k on it owned by two nice old ladies.
So I finally call the local dealer in rio rancho, don chalmers ford and talk to cliff in parts. He's been there quite a while. At first he has nothing for me but then realizes that I'm giving him a specification - w-blah blah blah. He picked up a bottle of ford gear lube and reads the spec on it and it matches. It is 80w90. He said the funny thing is this part number bottle used to read 'front differential fluid' but now reads 'rear...'.
When I rechecked the spec for REAR dif fluid on alldata, besides listing 80w90 it gives the very same specification as the FRONT dif. FURTHERMORE, cliff tells me that when he changed HIS dif fluids he went to synthetic 75w90 and gained 2mpg!
Now, how accurate that 2mpg is I don't know, but he makes a good point. I used BG ultraguard in my fr & rr difs which I keep on the shelf and did gain mpg's although I did other work decarbonizing, flushing the trans, and changing the transfer case fluid using bg's synthetic atf and friction modifier. I could also have used syncro shift in the tc but I wanted as thin as possible for mpg's on a long trip.
A word about gears and gearlubes: spur gears and helical gears can take up to a gl3 and 4 respectively (painting with a broad brush here) even a gl5 if the chemistry is right (don't want sulfur attacking brass syncros). But hypoid gears like a differential uses need friction protection because of high load and typically require a gl5. Putting atf in a differential is hard to imagine putting it mildly, considering it is more of a hydraulic fluid than a lubricant (although newer atf's are adding a bit of anti-wear agents and the like). Some front wheel drive vehicles have called for some pretty thin manual transaxle fluids but that is because by mounting the engine transversely no hypoid gears are used.
One last thought on changing the front dif fluid; I used an evacuator with a 1/4" line through the fill plug and got pretty darn close to all of the old fluid out. Nothing beats making sure there aren't chunks of something laying on the bottom but for all the trouble that appeared to be I was quite pleased with the results. I did take the cover off the rear dif and wiped everything off that I could there.