Which fluid for new trans and differentials?

[KC10Chief]

My transmission is currently being rebuilt. What brand fluid are you guys using in your trans? Regular old Valvoline or is the Royal Purple worth the money? How much will I need for my AWD van? When I took the transfer case off, a lot of fluid came out. Will the transmission fill it or do I need to refill it through the fill and drain ports on the transfer case after I get it mounted? I'd also like to change the fluid in the front and rear differentials. The van only has 74,000 miles on it, but it was built in 1997. I'm guessing the fluid has never been changed. What brand and weight would you guys recommend for the front and rear differentials? I'm putting $1,500 into a rebuilt transmission in a van that I bought less than two weeks ago. I am also replacing my rear main seal and the oil pan seal. I would like to get everything taken care of while I've got it on a lift. Anything else I should take care of while the transmission is out?

[AWDASTROVAN1999]

transfer case fluid is different .. you need gm autotraxx fluid $8 a quart at any gm dealer

[KC10Chief]

How many quarts does it take? Any after market stuff that will work?

[Phantom]

The RWD is 11.qts I



You getting a new converter?

[KC10Chief]

Thanks guys! This forum has been a big help with my van adventure I've been on lately. HA! So, I should be able to use any 80W-90 differential fluid in the front and rear diffs, but need that GM Autotraxx for the transfer case, correct? Yes, the transmission is being rebuilt with a new converter. He is also installing a hardened sun-shell and doing the valve body mod to alleviate any 1870 code and hard 1-2 shift issues that these transmissions are known for.

transfer case fluid is different .. you need gm autotraxx fluid $8 a quart at any gm dealer

Alaska excluded, I'm sure! It's probably $10 a quart, up here!

[AWDASTROVAN1999]

Its $8 a quart here in Pa .. I used 2 quarts to fill my transfer case .. The fluid is Blue in color

[paintdrying]

What type of fluid? Dextron 6? I would install a cooler as well. Is that royal purple worth the money?

[limon]

Hey KC10chief,

My mechanic doesn't believe in High priced synthetic fluids and used Valvoline Dextron, I believe - sounds like you're paying for rebuild, so I'd go with what he recommends for the transmission.
I used Royal Purple Synchromax in my transfer case, and Mobile 1 gear lube (the lower weight multi version, not the 140) in both diffs. I don't know if it will make any difference from what was in the van when I bought it, but I'm the king of deferring maintenance, so I want the fluids to last for the life of the van.

[Leeann_93]

Stop!

He has a '97, non-automatic transfer case (aka BW4472). Both the tranny AND transfer case take Dexron. I'd put in Dexron VI. You don't need high-priced, just a quality fluid. I use Castrol in mine (the Bravada).

You do NOT need AutoTrak II at all in your vehicle.

Automatic t-cases are '99+, the NP136.

[KC10Chief]

Thanks guys! The fluid that was coming out of the transfer case was red in color. Definitely not blue. I know because it leaked all over the floor! I'll ask the builder what he recommends as well. I appreciate all of the advice!

[Phantom]

I'll agree that Leeann is correct

I was reading a 99 manual in previous post

here is from the 97

GM published a Technical Service Bulletin for the transmission fluid as well as transfer case to be upgraded to
Dexron 6 , it is better than Dex3

I also prefer Castrol Dex 6

[KC10Chief]

Thanks! I'll get some Dex VI. I was at O'Reilly's tonight and the Valvoline Dex VI was $10 a quart! OUCH! It's going to cost me over $100 to fill this thing. The O'Reilly brand was about $7.50 a quart. I'd rather have whatever is best. I'm guessing that it won't be returned to me full of fluid. I'll talk to the builder and see what I need. For the front and rear diff's, I can't find any 80W-90 fluid. I've looked at a few places. I saw a bunch of Royal Purple 75W-90. Is this stuff okay? Does it need any kind of additives? Thanks for all of the help!

[Lumpy]

There is a Royal Purple 80-90, but it looks like it only comes in 5 gal lots.
http://www.royalpurple.com/gear-oil-pp.html

Amsoil packages 80-90 in quarts
http://www.amsoil.com/catalog.aspx?code=AGLQT-EA

For me, gear oil and ATF are both one of those things that I'll change very infrequently.
So paying more for those is sensible for me. If I had a leaky old Frod that was burning
a quart of oil every couple thousand miles, I'd be nursing it along with the cheapest
oil I could find. But for a trans or rearend in good condition, I'd just as soon use the
10 buck a quart stuff. I shouldn't have to deal with that again for years.

Luckily for me, my GF's ex was an Amsoil dealer. He left one of those big 2.5 gal
jugs of ATF, nearly full.


Lump

[Leeann_93]

You'll never find 80w90 synthetic. The synthetic comes as 75w90 and that's what I put in mine, recommended by a GM mechanic. It seems to be much better in the diffs than dino 80w90.

I use Mobil 1, but Royal Purple should be fine. No additives. Synthetics have the additives in them already.

[KC10Chief]

Thanks! I'll go pick up some Royal Purple 75W-90 this afternoon! It's definitely not cheap at $20 a quart, but hopefully, I'll never have to worry about it again for as long as I own the van. I'll wait until tomorrow to figure out what the rebuilder recommends for the transmission and how much I'll need.

[Shad0wXCalibur]

FWIW, Walmart has the Super-Tech brand of Dex 6. It's just under $4 a quart here. Works good... I would think any Dex 6 works better than even the most expensive Dex 3.

[Phantom]

Thanks! I'll go pick up some Royal Purple 75W-90 this afternoon! It's definitely not cheap at $20 a quart, but hopefully, I'll never have to worry about it again for as long as I own the van. I'll wait until tomorrow to figure out what the rebuilder recommends for the transmission and how much I'll need.

The torque converter will hold about half of total fluid at about 5 -6 quarts
the transmission itself will hold about 5 quarts

I repeat about GM stating in a TSB Dexron VI is to be used , simply because some old school builders who are not used to using it will sometimes say only dexron 3 , some old school builders only go with what they have used personally , some 40 years ago when synthetics were first released they were not as good as advertised , but have in the last 30 years been proven to be better , but some old school builders will never ever get up to speed with the modern world

If you don't have a new converter you will be back in with bad fluid and shorten the trans life with contaminated fluid because you cannot fully flush out all those metal shavings out of the crevices inside the converter

[KC10Chief]

I am getting a new torque converter as well. It's coming with the rebuilt transmission. So, any old Dex 6 will work huh? I was at my local Wal-Mart the other day. I didn't see ANY transmission fluids. Maybe I didn't look hard enough. When I install the transmission, do I need to fill the torque converter first? How does this work? Put as much fluid as I can in before I start it?

[Leeann_93]

Yes, fill the torque converter first. Should take about a quart without spilling out when you install it. Then put as much in the tranny through the dipstick tube as you can before you start 'er up.

It's easier to get the gallon jugs, but it looks just like any other oil bottle/jug so you have to look at the writing on it. Yes, any Dex VI will work, but I do prefer Castrol.

[Phantom]

With the cost of tranny rebuilds and the hassle to remove and replace , don't scrimp on the fluid , get a good well known name brand , after you get it filled it will be a long time before you need to change , I'd stay away from any store brands , it may or may not be sufficient , it is supposed to be , but it not worth 20 bucks or so to save to find out later you hot happy ,

walmart does not carry a wide range of things , I get my engine oil there as it is cheaper cost to get Castrol high mileage synthetic , but I get my tranny fluid at Advance auto , Castrol Dex VI was about 7-8 dollars a quart last time I was there

Yea fill about 1-3 quarts of fluid in the converter before you put it on it may take a few seconds for it to seep down into the cavities so it will take a few minutes to fill , then before you start engine have a total of about 9-10 quarts in before you start engine and let engine run about 15 minutes , let it warm up in park for at least 5 minutes , check fluid level before you put in gear, then put in reverse , then first the reverse then park , fill a to the cold fluid level on dipstick , when ready to drive , drive about 15 miles just casual , no hot rodding , after fluid get swarm after drive fill to hot full level if needed