Hot Rods transmission fluid

Good explanation on why this has been told so many times.

 

We live and we learn, if we pay attention. HRP

 

JMO but I would change the fluid and filter wash out the pan and put some Type F in it and go lay some rubber. Throw a shift kit in it first. Lippy

 

I had a 79 Impala at the house that had about 150,000 miles on the original fluid,it would barely pull itself but after a filter and some new fluid it worked great until the car fell apart. I do not know why GM was the only one to not have a drain plug on the converter.

 

Whatever you did the first time seems to be working fine.

 

Cheaper than B&M Trick Shift. However shopping for Type F is like shopping for Dexron these day's.

 

Dexron VI is expensive but worth every penny. It is a full synthetic and if you can find GM service bulletin on its specs and improvements over Dex III you will be amazed.
I run it in every GM ****** on the trucks I have had. I was very happy with the temp drops I saw in the trans temp when towing my trailer.
I recommend spending the money on it.


Sent from my iPhone using H.A.M.B.

 

When my pal Chris built the transmission he installed a mild shift kit and it's just enough,I had a hard shifting kit in the roadster and it was a huge mistake for a street car, my wife was driving the car when a sprag gear snapped ,in retrospect it was a good thing.

The transmission was pulled and rebuilt and the roadster was much more enjoyable to drive without the constant neck snapping. HRP

 

Hi Johnny, I get type F at Napa here. and no I didn't mean put the shift kit on full kill . LOL.

 

^^^^^ That's good to hear. It's been 12 years since I've had anything with a TH350 and F-Shift Kit.

 

type F is on the shelf at O'reillys

 

Ya know that funny right there. I would have spelled it DexTron. I guess hooked on phonics will be my demise. I have not bought fluid in California in a ****s age, but what you hear at least around here is DexTron and not dexron. Just an observation nothing else.

So now the 20 dollar question, can you still buy type F transmission fluid? I still have some on the shelf in the garage.

Interesting thread by the way.

LOL we must have been typing at the same time.

 

of course you can. Great for the Ford guys. And it works in Chevys, too.

The TH350 isn't too picky about what fluid you put in it.

 

Just came from NAPA to pick up a belt and because of this thread I had to look. Low and behold, the rack was empty where the Dexron 1 & Type F belong's. That's the norm where I'm at many different outlets and when I ask why. "No demand for it" is the reply I always get.

 

Ok, I have been lurking long enough and am going to finally put in my two cents on this post.

I have owned and operated a transmission shop for 35 years, so I am not a new comer to the transmission industry.

Back in the day, the "wives tale" about changing the fluid on a trans that hasn't had much or any service over its life is a true one. Having a trans that has never had fluids changed over a long period of time or miles, then changing the fluid in many cases, has caused the transmission to fail sooner than if it was just left alone.
This was due to the cleaning agents and additives in the new fluid attacking the soft components of the transmission like clutches etc.

Generally whenever a customer wanted their fluid changed for the first time, in the cars life, and it had 75,000 miles on it or more, and the transmission was working properly, I would recommend they are just better off leaving it alone. The possibility of doing a good thing for the transmission, by changing the fluid, may cause it to fail sooner. Eventually the transmission will fail, but when is anybody's guess.
In business sense, that is a poor decision to make (lost business), but I have always acted, what I felt, was in the best interest of the car and customer.

Auto manufactures recommended changing the fluid and filter at regular intervals, like every 25,000 miles. If it was done like that its a good thing. If it is done at 75,000 miles or higher, for the first time, that can be a bad thing.
They also recommended to change only the pan capacity of the fluid, which is like 4qts. out of the 10qts. it holds. Only freshening up the existing fluid and replacing the filter.
Think about it. If all your blood was drained out of you and all new blood of the same type, from someone else, is put back into you, what will happen? YOU WILL DIE!

In recent years companies like Aamco started pushing power flushing transmissions, replacing all the fluid, stirring up sediment in the transmission etc, and flushing it out. Maybe that's ok with modern electronic transmissions, but I disagree. I feel that's a bad thing on a high mileage transmission, no matter what the vintage. Maybe modern friction clutches of todays designed transmissions can stand up to this, Im not sure, but older designed friction material most likely can not.
I feel that's just a gimmick they came up with to make more money, and your not doing you transmission any good by doing so. Then they are not even taking the pan off and changing the filter. In my opinion, its more important to change the filter, than it is to change to fluid.

Back in the day, I have literally seen transmissions where the customer drained all the fluid from the trans and torque converter and filled with all new fluid and a few weeks to a month, the trans failed.
Then upon dis***embly, the pan is loaded with friction material from the clutches. I have also seen friction material literally de-bond themselves from the steel they were bonded to, intact and not burnt.
So the new fluid actually caused that trans to fail prematurely.

Many older transmissions like Powerglides, TH350s, Fords have just a br*** type screen filter, that unless there is something going wrong will not clog up. Many others like TH400s, Mopars have a Dacron/fiber type filter that will plug up and cause problems.

If you have to change the fluid on a higher mileage or high time transmission, only change pan capacity and just freshen up the existing fluid.

When it comes to the different fluid types. I use only Dexron III/Mercon in everything I build.
Back in the day, GM had Dexron, Ford Type F, and I think Mopar was Type A.
Dexron III is compatable with all of those fluids.
Ford Type F was originally used in the transmissions from the 50s and early 60s that had bronze lined clutches and Ford for what ever reason just stuck with the same fluid through the 70s.
Dexron was updated to Dexron II in the late 60s early 70s. Dexron III came out with the addition of more electronics to transmissions.
Ford Type F fluid was notorious for chemically breaking down and varnishing up. The only way to clean up a varnished up transmission was to use decarbonizing acid (Gunk) or lacquer thinner. I have seen 50s, 60s, and 70s Ford transmission,s where the fluid was like mud and were terrible to clean.

As far as Im am concerned, I have seen all the claims, for years, about using Ford Type F fluid in any
transmission to make it shift harder and feel its more hype than truth. Maybe on a dyno it may be true, but not in seat of the pants.
Back in the day, as an experiment, I built a high perf. TH400 for my own car and used Ford Type F fluid. Drove it 500 miles to, make sure the trans was broke in, and then drained all the fluid out and put Dexron II back in. I saw no real noticeable seat of the pants difference in how it shifted after the fluid change.

Lastly, I am a firm believer in, if the components were designed to use synthetic oils and fluids like modern LS engines and modern computer controlled transmissions etc., by all means use them. If it was designed for conventional oils and fluid, use what it was designed for.

 

Back in the '60s and '70s most shops put F type in everything, had a non slip additive to work with
metallic clutch material in old FOMOCO trannies. B&M used to call for it before they decided money
was to be made by selling "Trick Shift". Your TH350 will like F Type, little later shifts in cold weather
but who cares.