Is Dexron VI a good choice for my transmission

[CLeming]

I plan to change the ATF in a 2001 Olds Alero with 95k miles on it. I know Olds came out with a TSB that stated that Dexron VI should be used, replacing Dexron III. Exactly why or what was said in the TSB I do not know.

I have done some reading on Dex 6, and found that some older Allison transmissions had seal compatability issues with Dex 6, pre 2006 I believe. I know i don't have an Allison transmission under the hood, but they are in the same family sortof- but should I have any worries in using Dex 6 in this transmission in regards to seals and leaking?

 

[JHZR2]

How well has the car been maintained? How well does the car shift? Treated harshly?

I'd switch to Dex VI, though the no-name D/M fluids would be OK too.

 

[Bluestream]

Do you have the Getrag 5 speed tarnny? I have the TSP you are looking for

 

[CLeming]

Originally Posted By: Bluestream
Do you have the Getrag 5 speed tarnny? I have the TSP you are looking for



That I am not sure of. All I know is that it is a 4 cyl, 2.4L.
As far as how it has been treated and maintained- it shifts fine, and has been maintained very well. First ATF change was at 50K.

 

[beast3300]

If it is automatic 2.4L then it is a 4T40-E transmission and you will be 100% fine with Dex6 in that application.

 

[CLeming]

Yes its automatic

 

[Bluestream]

Originally Posted By: CLeming
Yes its automatic


In that case you can run the thinner DexVI. I use Mercon V in our Grand Am as its closer to the Original Spec DexIII just to avoid any problems

 

[partspro]

Not sure why you would use a ford spec fluid (mercon 5) in a gm transmission. Dex 3 is available everywhere and valvolines high mileage variant is a great fluid. Transmission fluids tend to be separated by the additive package which mainly affects the friction modifiers. Type F is highly friction modified, absolute requirement for the brass clutches used back in the day on Ford C4 and C6 transmissions. Newer spec fluids have less friction modifiers due to paper fiber clutches and more recently carbon fiber materials. BTW Ford strongly recommends not to mix up regular Mercon (same spec as Dex3) with Mercon 5

 

[KCJeep]

I did it and regretted it. Thinking I was doing my 2004 Venture a favor, (originally spec'd for DexIII) I gave it a partial fill of Dexron VI. Then the troubles started, the transmission had been just fine prior to that.

I can't say for certain the Dexron VI was the culprit, but it was an amazing coincidence. If I had it to do over I'd keep a nice fresh fill of the original fluid in it. I believe at this point I've cycled all the Dexron VI out of mine and it is better, although it's not yet quite back to it's old self.

If memory serves, after I first experienced issues I did an internet search (too little too late) and found other GM owners who'd had similar issues converting older vehicles to Dex VI.

My issues were not leaks, but transmission shifting issues.

 

[wiswind]

Most Mercon V rated fluids also meet the Dexron III specification.
The Mercon V is a bit tighter specification than the Dexron III.
As for Mercon, FORD has changed their stance on Mercon/Mercon V and now say to use Mercon V in all Mercon applications.
The older "do not use Mercon V in Mercon applications" TSBs have been superceded by the new TSB that states to use Mercon V in all Mercon V and Mercon applications.
If you do find a old Mercon fluid, they say NOT to use it in a transmission that originally called for Mercon V.

I had a Ford transmission that called for Mercon and remember the warnings to NOT use Mercon V.
Ford was having a lot of transmission issues at the time.
I don't know if they changed something in the Mercon V specification or if they tested the Mercon V in the older applications and decided that it was not an issue.

I was using the old version Mobil 1 that was Dexron III and Mercon specification rated....following the then current FORD TSBs.
Then I switched over to Redline D4, so I did not try the newer version of the Mobil 1 ATF.

 

[Bluestream]

Originally Posted By: partspro
Not sure why you would use a ford spec fluid (mercon 5) in a gm transmission.

Because its a similar spec and a way better fluid


Originally Posted By: partspro
BTW Ford strongly recommends not to mix up regular Mercon (same spec as Dex3) with Mercon 5
You must be using the "wayback machine" from Peabody and Sherman. Ford made that claim until they had used up all the Mercon fluid in stock and cancelled the licenses. Then it became magically okay to use Mercon V where original fluid was Mercon. Kinda silly when you think about it, but people believed them...

 

[CLeming]

Originally Posted By: KCJeep
I did it and regretted it. Thinking I was doing my 2004 Venture a favor, (originally spec'd for DexIII) I gave it a partial fill of Dexron VI. Then the troubles started, the transmission had been just fine prior to that.

I can't say for certain the Dexron VI was the culprit, but it was an amazing coincidence. If I had it to do over I'd keep a nice fresh fill of the original fluid in it. I believe at this point I've cycled all the Dexron VI out of mine and it is better, although it's not yet quite back to it's old self.

If memory serves, after I first experienced issues I did an internet search (too little too late) and found other GM owners who'd had similar issues converting older vehicles to Dex VI.

My issues were not leaks, but transmission shifting issues.


What problems did you experience? Firmer shifts, sloshy shifts?

 

[SteveSRT8]

Originally Posted By: CLeming
I plan to change the ATF in a 2001 Olds Alero with 95k miles on it. I know Olds came out with a TSB that stated that Dexron VI should be used, replacing Dexron III. Exactly why or what was said in the TSB I do not know.

I have done some reading on Dex 6, and found that some older Allison transmissions had seal compatability issues with Dex 6, pre 2006 I believe. I know i don't have an Allison transmission under the hood, but they are in the same family sortof- but should I have any worries in using Dex 6 in this transmission in regards to seals and leaking?


It does appear that some older units have issues, but they must be very isolated. We converted an entire fleet of Silverados and Savanas to Dex VI when it came out and it works wonderfully in all of them.

It is very high quality fluid, it just isn't the same as the ole' dexIII

 

[KCJeep]

Originally Posted By: CLeming
What problems did you experience? Firmer shifts, sloshy shifts?


It started to delay shifts, then it would "slam" shift. So we were getting delayed shifting and very hard shifting after the delay.

I'm no mechanic, but from my searches on line there were others with similar problems, the consensus was the DexVI flowed so much better it was giving the governor pressure sensor solenoid problems...unable to develop what it thought was sufficient pressure it would eventually shift anyway...HARD. We'd also get some slipping, always in the low gears.

I've rotated in DexIII several times since then and also added some Lubegard Red, it is much better but I'm not ready to call it "fixed" yet. The slipping seems to have stopped entirely but we still get the occasional hard shift.

 

[meep]

that sounds to me more like rubber seals swelling on solenoids. I experienced the exact same putting a non-honda fluid, commonly used with success here on bitog, in a 97 crv.

I ran Dex VI in an AW4-equipped jeep, which was original spec'd for Dex III, then spec'd to ATF +3, the ATF+4, and Dex VI was the best fluid I ever ran in it. Used Valvoline.... reputable products.

M

 

[wtd]

I run Dextron VI in my 2004 Monte Carlo SS which speced Dextron III and it shifts fine. I bought this car used two years ago with 87,800 miles on it and changed the fluid soon after.

I recently changed the fluid in my 92 Cavalier with Supertech Dextron VI and it shifts fine. I think it specs Dextron IIE. This is the fist time I used the Dextron VI in this car. Before that I was running a generac Dextron III. Car now has 161,400 miles on it and I bought it 5 1/2 years ago with 76,600 miles on it. I think this is the third transmission fluid change I've done since buying it.

Wayne