transmission fluid

[bigred07]

so its time for an oil change, but i was wondering about other fluid in the truck as well such as transmision transfer case and differentials. i don't know much about this stuff. i saw on an episode of truck U they emptied the rear diff of a truch and removed the back cover and swept out any little grinded pieces and replaced the fluid and what not. so my question is how often should you replace those fluids and what kind of fluids goes in each part then how you do it. i have an 89 se v6 4x4 that i bought used with 140000 miles now and don't know if any of those fluid changes have ever been done.

[MY1PATH]

every oil change I drain 90% out of; Brake, Power Steering & Clutch resivors using a syringe. Then I top them off with new.

This really isn't necessary but its a good way to make sure the fluids say clean and since the interval is so often and it evtually mixes downsream there is less need to do full sevice bleeds to get all the bad fluids out. Just make sure when draining that you leave enough in the resivor to keep air out of the system or you will be defeating the purpose.

I do transmission, t-case and differentials every 2 years or less. Diffs I check after any time I've had my axles spinning in water. Don't know what the reccomended schedule is but that what I do.

Bug juice- when its empty

Coolant, maybe every 2yrs I'll do a complete flush(pull block plugs, run a garden hose straight into upper coolant neck.), and every year I change out @ least a gallon just to keep the rust inhibitors fresh.

I prolly do stuff more than I should but oh well, can't hurt it.

[94extreme]

do you have owner's manual? suggested fluids are in there. i say that as they changed a few recommendations here and there and i don't know exactly about you 89.

 

some of the earlier t-cases had gl in them.. most latter had atf in them. etc.. if your truck is manual then i'd suggest just going to all the same GL4 <-- very important in the tranny, in all diffs, tranny and the TC. i went that way and like it as i only have to deal with one kind of oil.

 

as to exchanging these fluids: lay down under the rear pumpkin and have a look. there is bolt in the underside with a square hole.. a ratchet handle fits in there.. but first find one just like it that is higher on the diff. undo that one first.

 

same goes for the t-case and the front diff.. same deal there.. undo the upper bolts first..

[bigred07]

thanks. no i don't have the owners manual, no idea who does. so you can change the diff. fluids just like oil just open the top first then drain it and put more in the top hole?

[Precise1]

Yes. You remove the top first because sometimes they can be siezed/corroded/rusted in place quite firmly and wouldn't it be a drag to drain the oil and then find out you can't get the fill plug out??

 

So, top first, then bottom to drain. The bottom should have a magnet in it so wipe off the swarf and put it back in. Some people don't but I use a single wrap of teflon tape to avoid siezing down the road and insure a good seal. The only things I do is only 1 wrap of tape and 1-2 threads below the thread lead so none of the tape will be poking into the diff case. Make sure to wrap the tape so the trailing end is away from the clockwise tightening motion or it will immediately pop off.

 

Make sure to use the right oils and LSD compatible if you have LSD. There is a thread around on what is used where. I'll see if I can find it, but in the future, advanced search is your best friend...

 

B

 

Here is a thread. The only difference for an 89 that my manual states is GL4 75w-90 for the transfer case, not ATF. Lucas oil stabilizer is a good product for oil additives.

http://npora.ipbhost.com//index.php?showto...8&hl=fluids

Edited May 16, 2009 by Precise1
updated