TH350 with Ford ATF

[54blackhornet]

The TH350 in my 71 GMC was always slow to shift between gears. Exspecialy going into 3rd. I read that using FORD ATF instead of Dextron might help improve shifting. I dropped the pan and found some Shiny bits but not much at all considering the transmission is 47 years old. Results are impressive, crisp shifts now. I will update if I experience anything out of the ordinary.....

[AussieinNC]

Depending on how much FORD ATF you put in, you most likely now have a mix of old Dextron and FORD...

TH350's shift quality is controlled by the modulator and the valve body pressure springs, plus the clearances in the clutch packs.

You are feeling a better shift quality most likely due to the FORD fluid having seal softeners built n, whereas DEXTRON, especially early blends, does not.

A 47 year old trans that's still running is an exception to the rule...good luck with it...but it will eventually require an overhaul....

[jjzepplin]

In for the destruction! Maybe not.

[KQQL IT]

The man that built all my automatics ran type F in a his new builds and fluid changes.
Said it was better?

[too much stuff]

Originally Posted by KQQL IT

The man that built all my automatics ran type F in a his new builds and fluid changes.
Said it was better?

I also was told this back in the day. That was to use the actual type "F". I don't think it is as true now a days with the type "FA" or what other combinations there are.

[jjzepplin]

You guys are freakin me out! Won't my Chevy be mad that I am using Furd fluids?

[hugger6933]

I used to run type F in my bracket car the had a powerglide with a .500 brake then later in the glide I put in with the pro tree brake[ it was a 1,82 low as opposed to the 1,76 in the first.] everyone I knew of their goings on also used a type F in their transmissions. Good luck to you I know that the type f is ok to use in the older trans. Not like today where you have to use Dextron 43 synthetic or what ever number they are up to now.

[jjzepplin]

SO to do this you would have to drain everything including the converter?

[Jrainman]

I was on my second round of using Castrol Transmax dex V1 atf its a synthetic blend that gave me 50,000 miles on my TH400 , with much improvment as far as crisp and responsive shifitng . the first thing I do in all my older tranmission is install a drain plug ,do my fluid and filter change then run it for a week then dump it ,at this piont i feel im about 80 percent change I then run it for month or so then do it again ,pull the plug and change , then I let it run for the 50,000 and did a dump and filter change the old fluid only had a minimal color change a week later pulled the plug and refilled , 3000 miles later I did pull trans out to replace it with a 200 4r because I drive it every day , but will be using this trans in my 69 project even though my 69 has a th 400 in it I feel confident in that trans , over the years I have done this to my 2 sons used cars and trucks they have bought and never had any trans issues weather it was a chevy, dodge,acura,ford , Bmw and all these cars and truck pushed well over 230,000 miles ,I used the castrol Transmax line in all of them except for the BMW .

[Steeveedee]

Back in the day we used B&M Trick Shift. Supposedly it is the same as the old Ford Type F, or so I have been told (but a lot cheaper). The only time I ever used Trick Shift was when I put a Trans-Go shift kit in my '66 LeMans with a THM400. I couldn't tell you if the Trick Shift did anything, based on the performance. I've gotten plenty good results with the basic B&M shift kit and just GM type fluid, even with aged transmissions.

[feller]

A few years back I had a 200 4r rebuilt, the transmission guy told me to put type F in it when I re-instaled it. He claimed it was thicker and would work better with the shift kit he put in it.

[darrellyates]

We always ran type F automatic transmission fluid when we rebuilt power glides, and turbo 350's and 400's.

Haven't done it so much, as the newer Dexron is much improved over the old stuff...

However, back in the day, we ran Ford fluid in every GM product we had....

Never had a problem, actually believe it worked better than GM.

I still use Ford friction modifier in every differential I rebuild or change fluid in. Much better product than any other over-the-counter friction modifier I've ever used... Runs quiet, lasts forever....

[kaycee]

I run the Mercon V in my 700r4 on the recommendation from the builder, hasn't failed yet (4yrs)