Need help! Can't Find what kind of Trans oil I need

[1994Shy]

Hi everyone. I just aquired a 1994 4wd cheyenne 5.7 Auto. 194,000 miles. I have been a ford guy for a while but I wanted something I could work on myself and that would last the test of time. I want to do a transmission filter and fluid change ( not a flush) and rear-end oil. I have no idea what maintenance has been done. I looked up the vin but found nothing on what oil to use in the transmission or rear diff. I NEED HELP...!

 

[JOHNGAAA1]

Dextron III transmission fluid for the transmission. Rear end and front end are 80w 90 gear oil. If you use synthetic gear oil then you do not need the limited slip additive. Service the transfer case while you are there. It also takes the dextron III transmission fluid.

 

[df2x4]

Transmission (4L60E/4L80E): GM Dexron 6 (Dexron 3 will work fine and is what they originally called for, but 6 has superseded 3 and is a better fluid)

Transfer case: Dexron 3 or ACDelco 10-4033 manual transmission fluid (Dexron 6 is not recommended in transfer cases that originally called for Dexron 3)

Differentials: GL5 80W-90, with NO friction modifiers or additiives if you have the factory G80 locking rear differential. Be careful as lots of gear oils already contain friction modifiers. I use ACDelco 10-4051.

 

[1994Shy]

The tag is missing on rear diff so I don't know what type it is. I know there's a way to check by rotating the wheels or something like that. Thanks for the responses. !

 

[1994Shy]

It kinda makes me nervous touching the transmission though. I did a filter and oil change on an old Cadillac and it made the transmission slip and eventually blow

 

[Schurkey]

I did a filter and oil change on an old Cadillac and it made the transmission slip and eventually blow

Not unless you did it wrong.

If changing fluid and filter "caused problems", the trans was already damaged and would have failed anyway.

"I" would absolutely flush the trans fluid. Remove trans cooler "inlet" tube at the cooler. Let the tube spray into a bucket or drain pan. Start engine, run only long enough for fluid level to get low in pan--Stop engine the moment fluid begins to sputter out of tube. Drop and clean the nearly-empty pan and magnet, replace the filter. Install clean pan/magnet. Fill with 5 quarts of fluid, open ten more quarts so they're within reach and ready to be dumped into transmission. Start engine, dump fluid into dipstick tube as fast as it will flow. Watch fluid spraying into drain pan--when it's bright-red and virgin-clean, shut off engine, re-connect cooler tube. Start engine, top-off fluid as needed. Last time I did this--2003 Trailblazer 4L60E--I used fifteen quarts of fluid. Wouldn't hurt to have a few extra, unopened, in case you need more. You could always return the extras to the store.

Dump old fluid back into the empty bottles for disposal/recycling. The parts-store you buy the fluid from may offer recycling as a customer convenience.

Dextron III transmission fluid for the transmission. Rear end and front end are 80w 90 gear oil. If you use synthetic gear oil then you do not need the limited slip additive. Service the transfer case while you are there. It also takes the dextron III transmission fluid.

There's no "t" in Dexron.

There's no need for limited slip additive no matter what differential lube he uses. In fact, if his Service Parts ID tag on the glovebox shows "G80", he should avoid limited-slip additive. In this case, I'd drain the front axle before refilling--might as well get all the old lube out of the front, along with any wear particles that have accumulated.

Agreed on drain 'n' refill transfer case.

I'd also flush the power steering fluid, and maybe add a PS filter in-line with the return hose.

'Bout all that leaves is engine oil and coolant; along with air and fuel filters.

 

[df2x4]

The tag is missing on rear diff so I don't know what type it is. I know there's a way to check by rotating the wheels or something like that.

Like Schurkey mentioned, check your RPO codes on the sticker inside the glove box. If you see G80 on there, you have the factory locker.

 

[GoToGuy]

You can use the codes on the glove box lid and get all the info on what your truck was built with or option installed.

 

[1994Shy]

Had no idea there was anything in the glove box. I'll check it today.

 

[1994Shy]

Not unless you did it wrong.

If changing fluid and filter "caused problems", the trans was already damaged and would have failed anyway.

"I" would absolutely flush the trans fluid. Remove trans cooler "inlet" tube at the cooler. Let the tube spray into a bucket or drain pan. Start engine, run only long enough for fluid level to get low in pan--Stop engine the moment fluid begins to sputter out of tube. Drop and clean the nearly-empty pan and magnet, replace the filter. Install clean pan/magnet. Fill with 5 quarts of fluid, open ten more quarts so they're within reach and ready to be dumped into transmission. Start engine, dump fluid into dipstick tube as fast as it will flow. Watch fluid spraying into drain pan--when it's bright-red and virgin-clean, shut off engine, re-connect cooler tube. Start engine, top-off fluid as needed. Last time I did this--2003 Trailblazer 4L60E--I used fifteen quarts of fluid. Wouldn't hurt to have a few extra, unopened, in case you need more. You could always return the extras to the store.

Dump old fluid back into the empty bottles for disposal/recycling. The parts-store you buy the fluid from may offer recycling as a customer convenience.


There's no "t" in Dexron.

There's no need for limited slip additive no matter what differential lube he uses. In fact, if his Service Parts ID tag on the glovebox shows "G80", he should avoid limited-slip additive. In this case, I'd drain the front axle before refilling--might as well get all the old lube out of the front, along with any wear particles that have accumulated.

Agreed on drain 'n' refill transfer case.

I'd also flush the power steering fluid, and maybe add a PS filter in-line with the return hose.

'Bout all that leaves is engine oil and coolant; along with air and fuel filters.

Maybe your right about the flush. Sounds like new blood all the way through the system will be better