Changing auto transmission oil on 72?

[Slammed72blazers]

what type of oil should i use for my Th350 automatic transmission 4x4? Does Dex/merc work or just Dexron atf, any opinions, thanks

[Torrey72]

Buy the cheep one
Dexron is for GM and Dex/Merc is for GM and Ford

[Slammed72blazers]

So it doesn't matter either oil works right? Thanks

[gcburdic]

and welcome to the boards slammed....I found this thread that discusses your exact question....hope it helps ya...

http://67-72chevytrucks.com/vboard/s...d.php?t=520209

[GASoline71]

Get the cheap auto parts store brand Dexron. The new Dexron is compatible with old transmissions.

Gary

[clinebarger]

Originally Posted by Slammed72blazers

what type of oil should i use for my Th350 automatic transmission 4x4? Does Dex/merc work or just Dexron atf, any opinions, thanks

Run Dexron III.

Cheap Aftermarket Dexron III "type" fluids are labeled DEX/MERC, And are NOT approved by any OEM. These fluids do work, BUT they are not tested to any standard, No viscosity or oxidation stability test. You have to trust a "bargain basement" fluid maker for their word.

Stay away from Dexron VI ATF, It has caused seal damage/hardening in some transmissions that were made before 2006, GM says its backward compatible, But they are not fixing any seal damage.

The ONLY Dexron III fluids to have a OEM licence are TES 295Fluids approved by Allison.
TES 295 Approved Automatic Transmission Fluids.
Castrol/Allison........................TranSynd
BP Lubricants.........................Autran Syn 295
Cognis Corporation..................Emgard 2805
International..........................Fleetrite Synthetic ATF
ExxonMobil.............................Mobil Delvac Synthetic ATF
John Deere & Company.............HD SynTran
Volvo Trucks North America.......Bulldog Synthetic ATF

[storm9c1]

Is Dexron VI the new fancy synthetic stuff? Because I was told by a local shop to use the new synthetic stuff in my freshly rebuilt 4L80E (production date circa 1994, but rebuilt in 2010) on the initial fill. I already had plenty of stock of Dexron III in my garage, so I used that instead. It didn't feel right using an untried (by me) fluid in an older style trans that I just spent $$$$ to rebuild. I knew III would work, so I used it. I've also read that the synthetic stuff is great to run in any trans. Now I'm worried about what you are saying. Luckily I wasn't a guinea pig...

[clinebarger]

Originally Posted by storm9c1

Is Dexron VI the new fancy synthetic stuff? Because I was told by a local shop to use the new synthetic stuff in my freshly rebuilt 4L80E (production date circa 1994, but rebuilt in 2010) on the initial fill. I already had plenty of stock of Dexron III in my garage, so I used that instead. It didn't feel right using an untried (by me) fluid in an older style trans that I just spent $$$$ to rebuild. I knew III would work, so I used it. I've also read that the synthetic stuff is great to run in any trans. Now I'm worried about what you are saying. Luckily I wasn't a guinea pig...

Dexron VI was formulated for Hydra-Matic 6-speeds....6L80E & 6L90E.
It has a special additive package to deal with "clutch to clutch shifting".
It is labeled a synthetic.....DEXRON-VI is not synthetic. It is made from a blend of Group II and Group III base oils plus the Dexron VI additives package. It does not contain any PAO (polyalphaolefin) found in group IV base oils.

A "true synthetic" uses Group IV base oils.
All TES-295 approved fluids use Group IV base oils plus a Dexron III additive package...Making them a Fully Synthetic Dexron III fluid.

[GASoline71]

Good info clinebarger!

Gary

[gcburdic]

[storm9c1]

Great info indeed.

But OK, I can be dense sometimes........ so bear with me.

This (link below) is what my trans shop recommended for my 4L80E. I did NOT use this. Instead I used a supply of Dexron-III that I had laying around.

http://www.wolfshead.com/specsheets/trans.pdf

This unique fluid is specially formulated to provide twice the service life of a DEXRON®-III (H) ATF and offers enhanced performance for both new and older transmissions. It is particularly recommended for use in new GM 6-speed automatic transmissions, and is fully backwards compatible with older GM automatic transmissions.

So you are saying NOT to use this stuff (VI) in anything but a new 6-speed (ie: 6L80E)? I'm taken back at why he was highly recommending it (the "synthetic" VI stuff). He even told me to flush my other transmissions (mostly 4L60Es) and also replace then with this new fangled "synthetic" stuff.

Interestingly, the new fad is to indeed switch to using this "synthetic" Dexron-VI...everybody is praising it on other forums for how much longer it's "service life" is.

Basically, it's all hype then and should not be used in older transmissions? I want to get to the bottom of this debate. I'm all for not following the fads if I'm going to damage an older transmission...........

[clinebarger]

Originally Posted by storm9c1

Great info indeed.

But OK, I can be dense sometimes........ so bear with me.

This (link below) is what my trans shop recommended for my 4L80E. I did NOT use this. Instead I used a supply of Dexron-III that I had laying around.

http://www.wolfshead.com/specsheets/trans.pdf



So you are saying NOT to use this stuff (VI) in anything but a new 6-speed (ie: 6L80E)? I'm taken back at why he was highly recommending it (the "synthetic" VI stuff). He even told me to flush my other transmissions (mostly 4L60Es) and also replace then with this new fangled "synthetic" stuff.

Interestingly, the new fad is to indeed switch to using this "synthetic" Dexron-VI...everybody is praising it on other forums for how much longer it's "service life" is.

Basically, it's all hype then and should not be used in older transmissions? I want to get to the bottom of this debate. I'm all for not following the fads if I'm going to damage an older transmission...........

The seal hardening that ive seen is in higher mileage transmissions that have been switched to Dexron VI, A fresh rebuild would not have problems right away.....If it has the latest GM seals it WILL NOT be a problem at all if you run Dexron VI.
GM would never admit to screwing up! Not that Dexron VI is a bad fluid....Its just not 100% backward compatible.

The double "service life" claim is B.S......Most ATF's that claim the be full synthetics use ONLY group III base oils.....Mobil 1 ATF is a good example.
If you consider group III base oils "synthetic" Dexron VI is at best a synthetic blend?????

[Slammed72blazers]

Thanks for the information fellow chevy heads

[Weasel Diesel]

The double "service life" claim is B.S......Most ATF's that claim the be full synthetics use ONLY group III base oils.....Mobil 1 ATF is a good example.

How true. Allison said the new TES-295 would be ok for 100,000 ..... Then next thing ya know a service bulletin (Allison 1099B ) came out that now says 50,000.

[clinebarger]

Originally Posted by Weasel Diesel

How true. Allison said the new TES-295 would be ok for 100,000 ..... Then next thing ya know a service bulletin (Allison 1099B ) came out that now says 50,000.

Thats under "severe" use, "Regular" use is still 100,000.
http://www.allisontransmission.com/d...duct/1099B.pdf

[storm9c1]

This forum is great. Thanks Cline. Great info. My instincts were right not to trust what I read but rather trust other people's experience. I'll just leave the Dexron III in there and change it every 30K miles or 5 years then. Forget the expensive VI on my older stuff. I'll just put the VI in my Caprice PPV (6L80E) when that service interval comes due.

[augie]

Thanks for the great info clinebarger, it's now a part of the FAQ's here : http://67-72chevytrucks.com/vboard/s...d.php?t=523334