Transfer Case Fluid in Jimmys/Blazers

mrfritz44

A few days ago I noticed that I wasn't able to shift from 2 wheel to 4 wheel drive when the truck was cold. I would like to check/change my transfer case fluid but have no experience in doing so.

1. How hard is it?
2. What do I need to buy?
3. How do I do it?

I have a copy of Chilton's for this car, but I wanted to know if it was worth trying first.
Thanks, Fritz

0patience

Pretty simple. The hard part is refilling the transfer case. If you look at the back of the transfer case, there are 2 plugs, one at the very bottom of the back of the case and one about 1/3 the way up the back of the transfer case.
The lower one is the drain, the upper one is the fill. Pull the upper plug and then the bottom one and drain the case, let it drain for some time. Once drained, replace the lower plug and fill the transfer case thru the upper plug until it overflows. Then replace the plug adn clean up the mess.

There are two different transfer cases used in the blazers.
New Process 231, which is a manual shift transfer case. Uses 2.5 pints of Dexron IIE or equivelant.

New Process 233, electronic shift transfer cases. Uses 2.5 pints of Dexron IIE or equivelant.

Borg Warner 4472 AWD transfer case. Uses 3 pints of Dexron IIE or equivelant.

The best thing is to replace the fluid with DexronIII, since it exceeds DexronII's specifications and is readily available.

mrfritz44

That sounds pretty easy......no harder than an oil change I guess....correct? Any chance you know what size the plugs are? The reason I ask is that I have to use my dad's garage to do this and he doesn't have a full set of tools. I want to make sure I've got what I need before I head over.

Also, being a 1995 Jimmy with automatic transmission and not all wheel drive, I suppose mine is the New Process 233? Sorry for the redundant questions. I just like to know exactly what I'm doing before I start, less the process turn into an unexpected cluster.

This DexronIII, what does it cost and you're sure its safe to put into this thing?

Thanks again! Fritz

swschrad

and Opatience is a long-term mechanic with good contacts and a good rep. double-check the fluid type if you wish in the owners manual, but I trust him. dex-3 is to dex-2 like SJ oil is to SD oil... meets and exceeds all previous standards, so safe for the older service.

0patience

swschrad is correct, always double check the fluid types with your owner's manual.
The plugs on the transfer case will either be female 3/8" square plugs that require a 3/8" ratchet or breaker bar to fit into the square hole, or they will be 3/8" or 7/16" square plugs and use a cresent wrench [ouch] or 3/8" or 7/16" wrench to remove them.
Caution should be used if the are the internal square drive (female) plugs, it is extremely easy to strip out the square hole. Use a quality breaker bar if the plugs have never been removed. Use eye protection for the dirt and garbage that can fall in you eyes and in case you slip with the ratchet or breaker bar. I would suggest a pair of gloves too, to prevent tearing knuckles up.

mrfritz44

Thanks for all the tips. I'll be trying it out tonight. I bought an R/V Antifreeze hand pump that looks like it'll do the trick in case I can't use gravity and a funnel. For the $100 a GMC dealer wanted to charge me for this procedure, I don't mind a little frustration or bruised knuckles.

Have a good weekend.

mrfritz44

Did the fluid change and all went pretty well. The only pain in the butt was the large hex head plugs on the transfer case itself. I didn't have the correct socket size and had to use an adjustable...........bruised knuckles, go figure. The heads are very shallow and it was hard to keep the thing on them. But, after trial and error, I think I got them reasonably tight. It called for 40lbs torque, but I had no torque wrench so I guessimated. The truck moved pretty good as I tightened so I assume I got them tight enough. I figure the large amount of lock-tite I used should make up the difference if there is any. I figure I saved about 50 bucks from what the dealer wanted, and I got a new tool in the process so this offsets the cost even more.

Thanks for the help guys, Fritz

mookie14

i took my 03 tblazer into bp car wash and guess what scrtaches like you will believe. but minor to thin a little to the paint but not bad. what should i use to get them out????and how to do it.