TH 400 recommended fluid

What is the correct type of fluid to use in a TH400 transmission? Any recommended brands?o No: Any to avoid?

 

DEXRON-III and DEXRON(R)-VI are the typical off-the-shelf ATFs that you'll want to use in a ST or TH400. They are backwards compatible with the earlier DEXRON fluids. I have never had any brand preference or problems with one over another.

http://en.wikipedia.org/wiki/DEXRON

There are compatible synthetics available for high performance apps as well.

Type the word "dexron" in the search function for tons of reading.

Devon

 

I've always used Dexron III compatible fluid for the past 30 years pretty much since I started driving. :eek2: Hard to believe I'm that old.

In my younger days I had a lot of big boat type beaters with T400s and the first thing I always did was change the fluid and filter. I never had one fail which to this day amazes me. Guess a combination of a studry tranny design, maintenance and a little luck.

 

I am having trouble finding pure Dexron II or III. Everything I see is now Dexron/Mercon universal ATF. Any reason why I shouldn't use it?

I can find Dexron IV, but it is 3X more expensive!

- Bill

 

Use the universal...done the same here.

Devon

 

its the same stuff
randy:beers2:

 

Thanks!

- Bill

 

I use Type F

 

Modern trans. run much cooler than the older turbo 400's therefore the manufacturers reduced the quality of the fluids. The exception is the synthetic. Use it unless you want to change it every year. Much has been written on this. Larry mentioned a good brand but Mobil 1 and Royal purple Synth. trans fluid good as well.

 

I've used a 50/50 mix of hydraulic oil & transmission fluid in the past. It works much better than 100% fluid.

 

Optimum trans temp is said to be about 160-175*. I guess I doubt anything is running that cool these days.

As far as what trans fluid to use, I will just say that I just did a rather expensive 4L80E rebuild (with killer triple disc converter about $4300) and had no qualms whatsoever about filling it with house brand ATF in the gallon jugs.

We used expensive trans fluid in Sweesy's race 400 once, and used a store brand standard fluid the next time around, and I can honestly say we saw no difference in trans performance or temperatures. And if anything would test the fluid, that one would, with 750 ft lbs and a 5500 stall converter.

Just my experience and .02c

JW

 

Me too
Jamie

 

Sysnthetic fluid was too slippery for me. High gear would burn out but I'm talking racing.

 

I have heard that Type F helps the clutches work a little better, and am thinking about using it in mine (after I rebuild it).

I too, Bill, have noticed that about all you can find these days is a "universal" fluid. o No: And it is all WAAAYYY expensiveou:

 

buy it by the gallon. thats what i do and its always cheaper.
randy:beers2:

 

I would have to agree.

I have been experimenting with an 8" converter in my car and running plain old Dexron. Trans temp at the end of a pass has the gauge BURIED. This is the high end of 350* and the fluid looks fine. This is after about 50 passes.

As a matter of fact, I reused the fluid when I swapped converters this past weekend.

If you run any type of higher stall converter, be sure to run a cooler, it will save your fluid and your trans.

Jim

 

bump
heres an interesting thread
http://ls1tech.com/forums/drag-racing-tech/1516737-what-trans-fluid-race-built-th400.html
more specifically post #5 , #17 , #20