Need suggestions for 1995 Cutlass Supreme

[Klutch9]

My brother's '95 Cutlass Supreme with the 4T60-E transmission has started to weep very badly at the transmission pan gasket. I've done the repair before on my '97 Grand Am with the same trans (very easy job to change the gasket and filter), so the job itself doesn't really concern me. What I am wondering, though, is what fluid to use. Currently, the vehicle has 195,000 miles on it and, to my knowledge, the transmission fluid or filter has never been changed, only been topped up when needed because of leaks. The transmission itself still works great, no slips or flares. The manual specs Dex III, so I could use that. Dex VI supersedes Dex III and could also be safely used. Then there is the beloved MaxLife. I used maxlife at 165,000 in my 4T60-E equipped Grand Am and it worked a treat. Actually, the trans worked extremely well on anything...

The reason I debate is because the transmission is obviously high-mileage. The originally specced Dex III fluid is a little thicker than my other 2 options, at around 7.5 cst. The Dex VI and the MaxLife (which is a little thinner like the Dex VI) are around 6.1 cst. Would the thinner fluid work fine in an older car like this? Like I said, it worked well in my Grand Am, but it wasn't quite this high-mileage. What say you?

 

[redhat]

This is my experience, YMMV. I had a high mileage 3800 in a LeSabre. 180k and I did a filter and fluid change. I went with Dex VI.

The transmission did not seem right with the new, lower viscosity fluid in there. I dropped the pan and put another filter in there and filled it with NAPA Dex III eqiv. and a bottle of Lubegard ATF additive. Transmission shifted excellent and drove itself to the junkyard with 231k.

 

[tommygunn]

Maxlife will be fine. Remember, Maxlife products are especially designed for high mileage cars.

Also, if you don't already have one, there are aftermarket transmission pans with a drain plug.

Another good product is Mag 1 Low-Vis ATF. Synthetic ATF for $4pr quart at a value that cannot be beat! Link to Mag 1 Low-Vis

 

[sciphi]

Maxlife.

And, if you can snag a OEM pan gasket anywhere, do it! The aftermarket ones are pale shades of that beefy gasket.

 

[yonyon]

1995 was a long time ago. The 4T60-E likes seal conditioners. It might be a good idea to use an additive with your refill. Shrinking o-rings can leave you with that old "car doesn't go until engine coolant reaches 100°F" feeling.

 

[Klutch9]

Originally Posted By: yonyon
1995 was a long time ago. The 4T60-E likes seal conditioners. It might be a good idea to use an additive with your refill. Shrinking o-rings can leave you with ye olde "car doesn't go until engine coolant reaches 100°F" feeling.


I think that MaxLife would have plenty additives, though.

 

[bvance554]

With that many miles i wouldn't rock the boat. Drop the pan, change the gasket and filter and top off with Dex III

 

[GreeCguy]

Originally Posted By: bvance554
With that many miles i wouldn't rock the boat. Drop the pan, change the gasket and filter and top off with Dex III


+1

Keep in mind, you're trying to fix the leaking pan gasket. If every thing else is working, it doesn't need fixing. I would be afraid if you change to a different fluid and the transmission went south, your brother might blame you for breaking his "perfectly working transmission."

 

[Zaedock]

I would use Supertech Dex III and call it a day.

 

[michaelluscher]

Maxlife.

 

[CourierDriver]

If that fluid has never been changed and you drop that pan and add new fluid, say 5 or 6 quarts, it is a high probably your transmission will quit working shortly.......now,,,some shops will drop the pan, refilter the existing fluid just thru a strainer only and pour the old fluid back in and your transmission will be ok,,,,why? when you add new up to date fluid your new fluid starts cleaning out old stuff and sludge in there and that old sludge is the stuff thats keeping that transmission alive--- sounds stupid doesn't it,,,ask around for a second opinion please, and see what old transmissions guys say..

 

[threeputtpar]

With 195k miles on the original Dex III fluid, it's 100°C viscosity is probably pretty low already from 14 years of shearing. The Dex III from back then didn't really hold its viscosity all that well, hence the need for the new Dex VI spec that does hold up better. Putting MaxLife in at 6.1cSt will probably increase the operational viscosity from what it's at currently.

I vote for MaxLife or any licensed Dex VI fluid and filter change. Lubegard Red would also be a good suggestion.

 

[Whitewolf]

I would suggest DEXRON-VI followed by another change in 4 to 5K miles or 3 to four months, enough to thoroughly circulate. Remember that new fluid won't fix existing problems but the first change may release debris that you do not want in there. Oh, and no aftermarket 'additives'.

 

[Klutch9]

I decided to go with the Dex III. More specifically, I bought the SuperTech "Automatic Transmission Fluid" Dex 3/Mercon fluid. I'll be doing the job next Wednesday. I figured since the trans was on the original fluid and high mileage, the Dex III would be he safest bet to keep the transmission working well. Thanks for the input as always guys/gals!

 

[CourierDriver]

If you complete remove all the old fluid, please keep us informed on the results. I would still go to a transmission shop and get 3 opinions.