smooth~silver_type_s

guys, I'm getting my trans cooler installed tomorrow, and the directions say to drain the stock fluid, and to run redline high temp atf, on the comptech website. I have tried D4 redline atf, on my 2003 accord, and it thinned out within a few months. The manual also states that if you use a dexron 3 fluid, you should change it as soon as possible. Which would you guys use and why? I'm not sure of what the differences between the D4, and high temp redline fluid are, but I'm not sure the high temp won't thin out like the D4.

fsttyms1

I would use honda atf

smooth~silver_type_s

why then does comptech recommend it? especially for their tranny killing supercharger?

fsttyms1

??? Its not our fluid temp that gets high and destroys the tranny thats the problem. Its the lack of fluid to cool the 3rd gear clutch pack, and the tranny cooler does nothing to help

samkws

high temp ATF shifts bad under normal driving

i recommend the Amsoil ATF, but it's at 10 bucks a quart

SodaLuvr

RL D4 ATF is designed for street driving and has a normal viscosity of 7.5cst, which is a mid-20wt. RL High-Temp ATF has a viscosity in the mid-9cst range, and is designed primarily for track use. The High-Temp ATF's extra viscosity is unneeded under normal conditions; as far as how it'll affect shifting, I do not know.

All ATFs will thin to the low-6cst range after about 20,000 miles. This is normal and will occur with ANY ATF that originally started at 7.5cst. The High-Temp ATF will also thin but I have no clue how far down it'll go...7-8cst??? After shearing, the fluid will begin to slowly oxidize and thicken back up...as for how much, is something I do not know as I haven't run an ATF that long before. However, I will say that the new low-viscosity fluids with the enhanced additive packs are rock solid viscosity wise; these fluids will be the Dexron-VI, Mercon-SP, and Toyota WS-ATF. With the termination of GM's licensing of Dexron-III this year, you should expect to begin seeing Dexron-VI within the next year or two, and in the future, you'll see low-viscosity "Universal ATFs" using a new additive package from Infinieum as a next-generation fluid.

Comptech probably recommends the High-Temp ATF for enhanced wear protection during track use and high-temp conditions. However, the Hondas will not shift properly with D4 or High-Temp ATF alone due to the lack of correct friction modifiers for the Honda transmissions. Shifts may be much harder and possibly cause premature wear out.

I'd use their D4 ATF product and add Lubegard "Black" HFM converter (avaliable at Napa Auto Parts for $12 per 10oz bottle) to it at 1oz/qt of RL D4 ATF installed. That is, if you really insist on using it. This "mix" should work fine, and many transmission rebuilders use mineral Dexron-IIIH with Lubegard in their rebuilt Honda transmissions with no issues. The synthetic ATF and Lubegard should be fine for a long time, but of course, a pre-blended synthetic ATF is preferable.

smooth~silver_type_s

wow! you really seem to know your stuff. How do you think the honda ATF will hold up under track use? I did notice that the shifts in my 2003 accord were supersmooth at first usind RL D4, but slowly became much harder, than usual. I freaked out swapped out the RL D4 for honda ATF, and the harshness went away.

fsttyms1

I think honda fluid would hold up just fine to track use. And by track use what do you mean? a few laps down the 1/4 or a few hot laps around a road track? Remember what i said ealier, our trannies arent dying from tranny fluid thats getting to hot and not doing its job.

samkws

my tranny died coz the ATF was burnt...

causing overheating over a long time running on the track without cooling down

fsttyms1

Your fluid was burnt from the 3rd gear clutch pack over heating. no fluid on the planet will stop that