Hi, I have a 1993 4Runner with the 3VZE engine. I got the head gasket replaced after it blew. The repair guy replaced the transmission fluid. It used to be the red Dextron II fluid that I got from the Toyota parts department. Now, it's amber colored and I don't know what the tranny fluid is.

The tranny fluid is only halfway filled. I have spare Dextron II fluid and I want to top it off.

Is it advisable to top off my transmission with the red Dextron fluid when the transmission fluid already in the tranny might be a different type?

Looked on the Internet and I can't find an answer so I'm asking here.

 

Have you asked the mechanic what he filled the tranny with??
That might give a clue whether you could add the Dextron.

 

I have to go visit the mechanic to ask him.

But for future knowledge for my own sake, is it advisable to mix different types of transmission fluid?

 

If the additives in each atf is compatible you can. But that would be hard to research, I'd think.
Oil is oil. no one has access to special oil. It's the additives that make each oil unique. So they're not terribly helpful in revealing their ingredients for obvious reasons.
Same with motor oil

 

Some fluids might be compatible and some not. There is no absolute rule.
That's why you need to investigate what fluid your tranny was filled with.
Best case might be a flush and fill with 100% Dextron.

 

What you're really asking is: Can I get away with it.
Maybe.
Compare the possible benefit...save a few bucks, and possible detriment...damage the transmission and cost you a few bucks. Guess the probabilities of each course of action, assign estimated cost of each, and make your decision. Since nobody knows the answer, your guess is as good as anybody else's guess. My $0.02 and my guess: NO

 

Drain and refill to ensure it's the correct fluid and give cheap peace of mind. Not worth the risk to mix with no idea what it was.
I'd change the filter at the same time. Make it a transmission service to go with the new head gasket job. Do it right for reliability sake.

 

I'm not really trying to save a few bucks. If the tranny fluid that's already in my transmission is not compatible with the spare Dextron II fluids, then I am willing to acquire the compatible tranny fluid. The spare tranny fluid I have is the "official" Toyota brand (Dextron II that's colored red).

But what if I cannot get the tranny fluid that is already in my transmission?

I'm planning on going to the mechanic to ask him what type of tranny fluid he used. I hope he remembers the type.

 

FWIW, Toyota branded oil is Mobil. Toyota has been in partnership with them for ages. It's what comes in new cars, and what's sold on the shelf.

 

Have never seen amber colored automatic transmission fluid ever...not on any of my vehicles. All of it it has had the red hue color. I don't know what color Dexron 6 is, or whether it is backwards compatible with Dexron 3.

Valvoline Dexron 3 should be good to go in your truck. No use to spend extra money on Toyota branded fluid.

 

Yes, I've observed the same thing. Tranny fluid used at other shops or at Toyota dealers' shops are red. This is the first time I've seen an amber color. I observed this by using the tranny dipstick. It was red before the head gasket, now it's amber.

I need to go over to the mechanic to talk to him about it. Unfortunately, he is closed because he's on vacation until March.

 

New transmission fluid will turn colors from a light red to dark red to light brown, and to dark brown as the mileage on the fluid piles up. You sure it's not a light brown color? I have seen Dex 3 turn to a dark chocolate color. If it is light brown, that would indicate the fluid has a lot of miles on it.

Some gear oils are amber colored. It's going to have a strong sulphur smell to it.