Dexron VI for high performance.

[DJ]

I can find lots of talk on specs and reverse compatability but not much on folks having actually used it in an older application and maybe more importantly to me in a performance application.


I am thinking maybe I would go out on a limb and try the Dexron VI in my car and am hoping to get a few comments and honestly hope Terry and Mola in particular pop in. One thing attacting me is it is easy to find as a local GM dealership.

Application is a 96 Caprice 4L60E with roughly 400 RW hp

. Car is roughly 4250lbs with me raceweight(mostly drags plans for some AutoX), 4400 daily driver weight and I do drive it a lot.
Tranny is built to take the punishment, has a 3400 stall small diameter lockup torque converter heat is not a problem despite what "conventional wisdom" would suggest.
I spoke to the tranny builder and his only reservation was he was not sure about it's reverse compatability but it sounds as if that is not a problem???? He recommended Monolec 1150 and I will take it into consideration if you guys think the Dexron VI is not a good choice. Other considerations are Specialty Formulations I ran out of this but liked it, went back to order and he doesn't list Dexron anymore though being the great vendor he is though I bet he would work with me, and I was thinking maybe Shaeffer's might have something to offer.
At one point I had M1 in here and that di not work out well some guys are finding that this tranny under performance use does not like full synthetics

.

I really would like to have something I can get locally but if I need to go with something more exotic I will just make sure to always have at least a full extra fill onhand something I had failed to do when I bought the Specialty Formulations last time and because of it there is Walmart stuff in there now

it is working but I know I can do better.

 

[The Critic]

Dexron-VI should be fine.

Not sure why a full synthetic ATF would be a problem.

Schaeffer's is a good fluid with a proven track record, that only costs $1.00/qt more than Dexron-VI. But it's a Group III fluid now, so it's marketed as "Full Synthetic."

SF Dexron III(H) was GroupIII/IV/V, technically a synthetic as well, not sure why you didn't have problems with it?

Of the choices, I'd go with Schaeffer's in this application solely because of it's proven track record though.

 

[Pablo]

quote:

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At one point I had M1 in here and that di not work out well some guys are finding that this tranny under performance use does not like full synthetics

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What kind of problems were these guys having? Amsoil ATF and ATD better, Amsoil ART have been used for years in racers with greater than 500 RW HP with no issues.

 

[unDummy]

Nope, I wouldn't use a thin fluid. I'd stick with a regular Dexron III, a synth blend, a full synthetic, or a racing ATF in that order(decision based on maintenance interval, usage, and logged average/peak ATF temps).

Sorry, I can't believe that Mobil1 or any synthetic would not work out. And, I would like to know what you mean by "did not work out" and how a tranny doesn't like full synthetics. Usually, the real issue is that some owners don't like the cost. The same cheapness with the fluid selection reflects in the cheapness with the rebuild and AT mods, which are where the problems occur.
And, a well modded transmission should really care less about the fluid used.

If it were my 4L60, I'd fill it with a full synthetic, add a real filter kit, add a trans temp gauge, and adjust the cooler size accordingly with an ATF thermostat. Lockup TC's really helps with trans temps. But, temps should still be monitored. 2+ tons and 400hp creates heat regardless of stall speed.

I don't know what weather is like in cheeseland, but if it gets cold, the more consistent all weather performance, with a synthetic, is definitely worth it if you drive the vehicle year round.

Without knowing specifics, my easiest recommendation is the TES-295 ATF or equivalent.

 

[DJ]

Guys are finding the clutches don't hold well with the M1, have not gotten much feedback on the Amsoil specific to my useage in this application. Cost is not a big concern for me I understand I have well over $2000 in the tranny and torque converter, cheaping out on fluid would be silly.
By does not run hot I watch the temps as seen by the pcm and since the tranny build and the high stall 190 is the highest I have seen and that was hilly driving, dropped it to "D" to keep the converter locked and straight back to 170 within a minute or two.

 

[unDummy]

"Does't hold well", that means you need to look at your pump, line pressure, ATF flow, servos, clutch/band type/#/size chosen, TCM programming, VB mods......

I'd also aim for a lower temp in the 150 range vs. the 170.

How about some build details? What does $2k buy these days?

 

[The Critic]

Yeah, really, $2000?

I can't even get a A604 or 4L60E rebuilt around here for that amount consistently.

 

[DJ]

quote:

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Originally posted by unDummy:
"Does't hold well", that means you need to look at your pump, line pressure, ATF flow, servos, clutch/band type/#/size chosen, TCM programming, VB mods......

I'd also aim for a lower temp in the 150 range vs. the 170.

How about some build details? What does $2k buy these days?

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Maybe you should consider the car has roughly 240% of the power GM delivered this particular car with. Far as the temps under 160 is known to cause some slip too in this tranny. I am of course talking under power not in normal driving.

This is a tranny most consider weak but a FEW folks can build it well, I am going on three years and 40K on this one car well modified that whole time. Before this I had a local rebuild go under less power in 16 months in that time the car went from 200fwhp to 320fwhp now it is closer to 480fwhp.

Critic, the builder is in CA actually and I am not including shipping back and forth in my rough low figure I posted. Today I think the 550hp rated package I have goes for about $1900 without R&R, the converter starts at about $525 these days but I have some upgrades done there too.

This builder does not use the latest wizbang parts which may be why it is not that expensive for such a high HP rated tranny, Vette servo, Transgo kit with Transgo vacuum modulator. Most of how he makes them last is by understanding the valvebody and necessary clearances and setting it up right, the shifts are quick and positive but not hard. I can PM a link but I don't think I am supposed to post one, the tranny was done by ProBuilt Automatics and the converter is an Edge racing converter.

In winter I want to be able to drive the car but will not do so regularly, this much torque is not a good thing in snow or even heavily salted roads. Last new years I took it to the dyno before the latest round of modifications and put down 290rwhp and it snowed while I was there, that was enough fun and now I have roughly 100rwhp more. A basically stock Roadmaster wagon serves winter duty.

 

[DJ]

Sort of a TTT and a little info on the actual performance of the car.
Last night it went 12.3 at 109 in the quartermile, which is sub-4 second 0-60mph

 

[Pablo]

Good deal! Which ATF? (I'd love a UOA on a race ATF)

 

[DJ]

An unplanned pan drop lead to me having to fill it with SuperTech

hence the hope of finding something good but readily available or at least will make me always keep a fill extra onhand. A UOA on this stuff is not in the plans. I had some Specialty Formulations in there and planned to use it longterm and UOA it but the pan drop interfered. Mola is not listing a Dexron anymore though.

Best part is this is still NA on a 100K stock LT1 shortblock, ported LT1 GM heads and a good cam.

 

[Whitewolf]

DEXRON-VI is only 'thinner' than DEXRON-III when it's new. The DEXRON-III fluid will shear rapidly and become 'thinner' than the DEXRON-VI. DEXRON-VI fluid also has much more stringent thermal stability requirements (have a look at the spec)

 

[DJ]

A week after I last posted in this thread I blewup the motor 100K mile bearings could not take that whipping I guess.
I had to drop the pan to redrill a single hole in the seperator plate a little bigger than the initial shift kit installation. Topped it off with Dexron VI at that time can't really comment on how it works because like I said I tweaked the shift kit at the same time. The pan was very clean no clutch dust despite the Walmart fluid that was in there, still plan to completely flush it and fill with Dexron VI.
Weather got better and I played a few games and managed 11.9 at 113 with another stock shortblock later in the season.

 

[adamsvega]

love the post .i had type f last with elevated temps in my drag cars with alot higher stall and trans brakes - 200+ passes on rebuilds last time out both boxes were filled with mopar(valvoline?) +4 they both started to slip at 130 passes the trans temps actually went up form previous fluids and the shift seamed to be softer . also noted the +4 took more time to heat up . would the add pkg. in the +4 cause the buffer on apply for passeger cars and slip on high load race conditions . i took both units down and tested them psi's were all in order . went back to cheap o type f . had 1 reccommend of a castrol 10w tranny fluid with a high flash point comes in bulk! what do the guys that know think . the over hauls were all the same stuff yr to yr. i dont mind the rebuilds but the trans needs to hold on the band and clutch side to be consisitant . any ideas!!!!

 

[unDummy]

Yep, ATF+4 could possibly cause some slip. Its AW/EP performance seriously reduces wear caused by friction compared to dexronIII which might explain the longer warm up time.

I haven't compared the DexronVI smoothness to other fluids yet. I would hope that since it is back compatible to all dex3 transmissions, that its not as HFM'd as ATF+4.

Try the DexronVI in one of the transmissions.
Redline has a racing ATF, and Amsoil has 3 fluids to choose from: ATD, CTG, and ART.

 

[DJ]

I have not raced yet this season but I have done some datalogging on a secluded country road and the rpm rise after the shift command till shift completion is MUCH lower than it used to be. Now the hole I redrilled affected 1-2 shift but did not affect 2-3 and that is exhibiting less rpm rise as well so from the little data I have sofar the Dexron VI is allowing the clutches to work better.

 

[Whitewolf]

I'm not sure that it's just a case of 'higher' or 'lower' FM.
The ATF+4 uses Lubrizol chemistry and the DEXRON-VI uses Afton Chemical chemistry so you would probably expect them to be different. Additionally the materials that the fluids are made to used with are different since the ATF+4 spec has tests in it using BW-2050 friction material and the DEXRON VI spec specifies BW-4329 for the plate test and carbon fiber for the TCC test.