mcgina

Hey guys, I was wondering if it's ok if I change out my trans and diff fluid with Redline MT90 75w90. I was researching and keep getting mixed answers that its okay to use it as transmission fluid, but more people say that its mainly used for the diff. I have 3 quarts I forgot about in my garage and plan on swapping flushing the fluids soon. I have an 2000 ap1. Please let me know!

Billman250

You cannot use that in the transmission.

Jdrum1

How come? There's a number of people on here running it (including some avid trackers), and I have yet to see anything negative about it (granted, it's not ideal for cold climates).

MT90 has silenced my mild 3rd gear grind (used it for a couple years now).

Billman250

It is not the correct weight for the oil pump in the transmission, and should not be used to hide an underlying problem.

Jdrum1

Makes sense.

I hope to eventually swap to an AP2 transmission.

In the short term, which is better; thinner MTF (thus, grind returns and), or MT90 (possible pump wear)?

Billman250

Honda MTF has proven best in the long term in my experience.

It wont cause pump wear, but it will affect the pumps ability to push it through the gear-feed tube (a steel tube with pinholes that shoots a fine stream of fluid in between each gear set)

Jah2000

Billman... What's your fave/recommended for rear diff? Mobil 1 okay?

mcgina

So is Honda MTF for tranny and Redline MT90 75w90 ok for the diff ok? planning on using those

LDfavoriteson

https://www.s2ki.com/s2000/topic/805...d/page__st__25

Paradoxicalcook

I had to have the 1st and 2nd gear set replaced due to using this fluid in MY05 for 10,000 miles from 7500 to 17500. Believe me, avoid the expense of having your transmission case cracked open.