I have a 4spd in my 87 f150 and was wondering what is involved in changing trany oil. What kind should i use and how often should it be changed. It doesnt slip or grind. Also what oil do you run in the differentials. I want to do a bit of work to it before it goes on the road and i have my dads nice warm barn to do it in.
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The four speed likely requires an 80W gear oil, and I run a 75W90 in the axle. It depends on the transmission as to how you'll have to change the oil. Mine didn't have a drain plug, so I had to use a hand pump to suck out the old oil.

 

If you have a limited slip differential don't forget to add the limited slip additive to your diff oil.
I think you're right on the gear oil for the transmission. My manual says 4-speeds from 92 & earlier use 80W, 93 and later use ATF.

 

Limited slip is when both rear wheels drive right

 

Yup, but if you use synetic oil, there is no need to add the friction modifier.

Depending on the 4 speed it can be ATF(aluminum case) or gear oil(cast iron case)

 

Eric, I think synthetic is the way to go for the LS diff's and if it works there wouldn't it work in the trans too...except for the "aluminum" case trans like the ZF's. You said you have a ZF in your 87, and it doesn't have a drain plug? My 90 ZF has a drain plug and I am always on the lookout for a spare trans. So if the 87 doesn't have a drain plug that would be a P.I.T.A at service time. so I'll check for that before I buy one. Thanks ...Dave

 

im not sure what kind of trany its got. i just know its a 4spd standard and thats all i know. how often do you all channge trany and diff fluid. should i cange the front diff oil too.

 

Not always the case (no pun intended). The original TOD four speed in my truck has an aluminum case and the Ford Service Manual calls for 80W gear oil.

What I said earlier was misleading when you put it together with my signature line. In my head I was talking about the original 4-speed overdrive I swapped out for the 5-speed ZF. The ZF does have a drain plug and as far as I know all of them do.

On a related subject, for transmissions that call for gear oil, will synthetic and the LS additive cause any issues with how well the synchros function?

I changed the rear axle fluid at 100,000 miles and now I'm rebuilding it at around 190,000 because the LS differential was trashed (it's been abused). The owners manual doesn't list a service interval (change when axle has been submerged in water) and Haynes says 100,000. I may shoot for 50,000 miles when I get mine all back together unless someone has information that says it should be more often than that.

I did the transmission fluid at the same time as the rear axle and didn't drain it again until I took it out to install the ZF, around 190,000 miles. I probably would have changed it more often if it had a drain plug and a fill plug you could hold an oil bottle up to. I'll probably change the fluid in the ZF every 30,000 miles or so.

 

Now I get it...you must go s l o w ...I'm old Lol !!! "most"synthetics say they will work with LS's. When I get home I will post a report evaluating ALL synthetics...BIG eye opener to me ... who passed & who FAILED ... changed my mind !!! Later ...Dave B-)

 

In the midst of these posts I got to thinking... someone must have done a "real" evaluation on synthetic lubes of all kinds... so on to the WWW (aka google) to seek the truth, here is what I found ... http://www.synthetic-oil-tech.com/Ge...te%20Paper.pdf I'm no computer wizz, so you'll have to copy & paste to get this report. I used to think Lucas products were the best ... not so much now. Amsoil requested this study and I guess paid for it but the results are interesting ... Oh yes it is a pdf file... what ever that means !!! Enjoy ... Dave

 

recently purchased a 99 F550 super duty, with a 6 speed tranny. is it a ZF or Ford trans? what fluid do I use in it?

 

It is a ZF and uses synthetic atf