CMDSlick

So the manual for my 93 LS400 calls for ATF T-II... and I know the successor is T-IV...

But nowhere can I find any info on the difference between the two. I'm curious if the the newer T-IV is a better oil in some way that will allow me to eek out a bit more MPG.

Can anyone shed some light on this?

Also, I'm pretty sure my tranny fluid has never been changed. 1993 with 35k miles, should I even care to change it? Not experiencing any issues that I know of.

RugbyDad

Ummm, I don't think you can even buy t-ii anymore, like anywhere. Soooo, I don't think it matters. Besides I doubt (see: definitely won't) you'll get any extra mpg from t-iv over t-ii. I've never heard of mpg benefits from atf.

For all intents and purposes, t-iv is t-ii. Mileage and time are somewhat equal in terms of wear on fluids. So 34k miles doesn't mean squat. 21 years definitely means something. I would change it before a problem arose. That's the whole meaning of preventative maintenance.

billydpowe

iTrader: (1)

So 34k miles doesn't mean squat. 21 years definitely means something. I would change it before a problem arose. That's the whole meaning of preventative maintenance.

I agree, moisture will accumulate in time, and that is your enemy.... period

RA40

iTrader: (6)

Change that ATF fluid out. The car may not have lots of miles but age is a factor with non sealed system fluids. That moisture absorption over 21 years is not one to circulate through the tranny.

Other than smooth shifting and fresh additive package your MPG will not be altered to any perceptible measurements.

Michael

Imagine that, 93 LS with only 35K miles on it. The car is practically new.

PureDrifter

iTrader: (10)

T-IV supercedes and replaced T-II. if your car was spec'd for T-II, use T-IV.

CMDSlick

Right, I'm aware that that is the new and yes RugbyDad you can't even get II anywhere. Back to my original question... Does anyone know what specs changed between II and IV?

CMDSlick

Oh and thank you for answering the questions on the tranny fluid as far as time is concerned. I was wondering, and that is very helpful guys.

RA40

iTrader: (6)

My wild shot is that the additive package has been modified for current tech: lubricity, longevity and molecule size were improved to provide less friction, better cooling, etc.

lextout

I wouldn't do a flush, just drain it out, its the same procedure you would as an oil change, yet easier. Just unbolt one plug from the tranny pan and it drains out a few quarts, do this every 3rd r oil change and your good. The type of oil now is t4

CMDSlick

Do you think that Type II was conventional and now Type IV is synthetic?

kevvo

Even though it's a very low mileage vehicle, I'd be curious at what might be floating around in the pan after so many years.
I'd drop the pan and check for any crud and gunk and if the box is anything like the 5 speed, clean the screens and replace the internal gaskets.

What do the experts say?

Sc400NL

is it no problem to mix T-II with T-IV ? when i just drain the pan and change the 2 quarts ?
or replace the full capacity ?

PureDrifter

iTrader: (10)

If your car has T-II in it, it's probably old as hell and in need of a fluid exchange.

that being said, no, no problem mixing them.

Sc400NL

not sure if it is T-II , i guess it is , i just did a drain and refill with Dextron T-II who is still available over here and did the oil change , i measured the old oil and fill the same amount of T-II , i don't think it had a oil change before since its a low millage car 90K miles

do you advise to keep change the ATF with T-II or start mixing with T-IV ?