friend mixed Type F with Dexron.

[DriveHard]

A friend of mine here at work owns an early 90's Chevy pickup truck. He let his brother borrow it for a few days. Being the kind brother he is, he noticed the tranny fluid was quite low and added several quarts of "Type F" fluid (obviously the truck had Dexron in it). My friend knows I am an oil geek, and came to me for advice. What are the risks of leaving it in there? I told him to drain and refill, but he is more than likely going to just leave it, as it "doesn't feel any different". Can you guys shed some more light on this?

 

[unDummy]

Several quarts

Shifts will be quicker, firmer, and more abrubt.

When very cold, shifts might be a little sluggish since cold weather performance of Type-F is as good as molasses.

Otherwise, nothing to worry about. Topping of with type-F is better then being several quarts low.

Let me guess, it was the cheapest ATF in the store

 

[Whitewolf]

Well, it's no surprise to anyone on here that, whilst I agree with UnDummy that you probably are not going to do too much damage,if the vehicle belonged to me, I would change the fluid. I would use DEXRON-VI with at least a double flush.

 

[onion]

He'll likely never notice any difference in performance. The auto tranny in the early 90's service truck at a John Deere dealer I worked for was filled with hydraulic oil... and it ran just like any other truck.

I wouldn't lose any sleep over it, but I'd probably at least do a drain & fill when I got around to it with the proper DexIII or DexVI or whatever floats your boat.

 

[JohnBrowning]

I would not worry about it. I ran all Type F in my 700R4 that I built for a while to see how much firmer it would make the shift's. Seeing how I drained the pan each time I changed oil It did not take long to put it all back to DexII or III wich ever Iwas useing at the time. Seeing how I had built my 700R4 for raceing it really did not make much difference in my transmission. I have heard from a lot of guy's though running stock GM transmissions that Type F will firm up the shifts. So I would not worry about it he will be fine.

 

[onion]

Quote:

---

I have heard from a lot of guy's though running stock GM transmissions that Type F will firm up the shifts.

---

I've heard that, too. But I tried it more than once back when I was young and dumb... and cared about things like a firm shift. I never noticed any difference at all in the turbo 350 transmissions that I filled with type F.

 

[MolaKule]

Unless you are going to race it, I would dump as much fluid as possible and refill with a good late Dexron III.

The Type F additive package is much different compared to the later Dexron.

 

[bruce381]

""The Type F additive package is much different compared to the later Dexron.""

Has NO friction Modifiers and will firm shifts BUT may also
cause undo wear and high loads on parts not designed for that.
bruce

 

[unDummy]

It really depends on how "several quarts" is defined.
There is still plenty of Dex in the transmission, I wouldn't worry about the Type-F.
A flush with type-f is something that could cause said issues. This wasn't a flush. Top off with TypeF is better then being low.

And, either owner or sibling does not know how to use the ATF dipstick. If it wasn't checked correctly, could it now be 'several quarts' overfilled? Would it function normally 'several quarts low'? Why even use type-f?

 

[Tremo]

Putting type F into a GM tranny is an OLD hot rodder's trick to firm up the shifts. You could get away with it back in the TH350 and TH400 days. Not so sure about today though.

 

[Colt45ws]

Ive done 3 or 4 change outs with Type F in my transmission as a bandaid from slippage. Works good, except when its cold as mentioned. I dont have an electronic transmission..If its early 90's it probably doesent either. I wouldnt worry about it.

 

[Whitewolf]

I would not advise putting a type 'F' fluid into the more recent transmissions. The transmission calibrations and friction systems are not geared for that type of fluid.

 

[Cutehumor]

if his trans was several quarts low, I say he has bigger problems that what type of fluid his brother put in

 

[Whitewolf]

I don't wish to be rude but just ask yourself the following.
What is the cost of a transmission?
What is the cost of fluid?
I'm not saying that any harm would/might result but I would play safe.

 

[oilboy123]

Leaks fixed?? Auto-rx?? change out to Dexron!!

 

[Whitewolf]

Well, just my opinion, but if I were in your situation I would still change the fluid. Also, I wouldn't touch any of those aftermarket 'additives' with a barge pole.
Here we go again, more controvesy I think! but isn't that a good thing? Healthy debate!

 

[Gary Allan]

He'll shed more metal. Some 70's rebuilders used TYPE F for all of them. Firmer shifts.

The original TrickShift was DOUBLE SUPER TYPE F You would 'erode' your trans away.

 

[Whitewolf]

Well as you know a real 'type F' has no FM, so firmer shifts for sure but as you say, at a cost. That's why I would get it out of there.

 

[oilboy123]

Took Trick Shift to just now finally come up with a syn fluid......