Hey guys,

I am wanting to change my transmission fluid, manual transmission, it’s at 200,000 miles and I don’t know if the last owner ever changed it, is it bad if it hasn’t been changed to replace the fluid? Hoping you guys can help.
Thanks

 

It will be fine to change it. Manuals dont have the same fluid issues associated with automatics, when they dont have the fluid changes they require.
Just make sure to use reccomend GL-4 only fluid. Not GL-4/5. That stuff can make the shifting a little clunky or notchy

 

Sounds good, which brand would you recommend ?

 

Whatever is cheap. If you have never changed it, anything will be an improvement.

People say the expensive synthetic stuff shifts better. It doesn't in my experience. I have ran it several times and couldn't ever tell a difference.

 

I change all fluids when I buy a vehicle. Peace of mind. One vehicle i dragged home had "chunks" come out of front diff with the oil!
Changed all gear and transmission oil last week in my '91 Toyota to full synthetic 75 90. You may want to consider synthetic for your transmission and diff if you are in a stinking cold climate. Otherwise just 80 90 dinosaur oil.

 

Redline mt-90 is what I run and am very happy with. I made the mistake of putting some kind of GL4/5 into my trans when I did the first fluid change and it shifted very notchy and would grind 1-2 every time. Did some reading on here and switched to the redline fluid and all the gritty feeling and grinding went away. I'm a believer.

 

I would definitely change out the old fluid.

You can't go wrong with Redline MT-90. It is the go-to gear oil for these old Toyota manual transmissions. It is expensive, but I think it is worth it.

 

Sta-Lube brand GL-4 90 Wt https://www.carid.com/sta-lube/api-g...n-sl24229.html

Most places carry Gl-5 spec gear oil nowadays. Back in the old days it was advised not to use GL-5 in transmissions because supposedly some chemical that was part of the GL-5 specofic chemistry would attack copper/bronze/brass components of the transmission...like synchromesh components. I don't think that is the case with newer formulations.

Last time I bought gear oil was for my Roto-Tiller and I found it at a hardware store; not available at several auto parts places I checked

 

GL-4 is best. Modern GL-5 gear oils won't attack the brass synchronizers, but GL-5 is slicker than GL-4 because it has to work in hypoid gear (sliding tooth contact) differentials. Synchronizers are basically friction clutches, and GL-5 is too slick for them to work well.

I haven't seen GL-4 in an auto parts store for years. You pretty much have to order it online. As has been said, Redline mt-90 GL-4 is a good choice. Expensive (I think I paid $60/gallon), but you don't need to buy it often. The transmission only holds a couple of quarts.

 

 

GL-5 is required in the differentials. You'll damage the ring and pinion with GL-4. As far as weight goes, 85W-90 is what I use.

 

My local NAPA stores stock Sta-Lube 85W-90 GL-4 in gallon jugs and quarts. Cheaper by the gallon. Wait until they have an online 10% off sale to save some money. Yes you can order online, and pick it up at the store. Done it many times at my local NAPA stores.

https://www.napaonline.com/en/p/SLRSL24239

I have used the Sta-Lube, and am using Redline MT90 right now. The only difference I can tell between the two is that the trans shifts a little smoother when it is very cold in the mornings. And then that advantage only lasts like a half mile or there about.

 

Good time to replace this while the shifter is out to fill the trans fluid...

 

For clarity... There is no need to pull the shifter bushing unless yours is sloppy. The fill port is on the side of the transmission, you don't have to touch the shifter at all to change fluid.