RB25 trans fluid

[WhatsADSM]

Looking for some help/opinions with my RB25 trans.

Anytime you up-shift the thing quickly it grinds pretty good. I am 100% sure the clutch is disengaging (HKS twin disk), and even adjusted it so it disengages earlier, but the problem still existed.

So that brings me to my next point. I am pretty sure the trans is on its last season, but has anyone had good luck with a particular fluid? I know in the past I have run royal purple (synthetic) syncromax or GM syncromesh and it has helped a little. Anyone have any suggestions?

And of course is there anyway to get a local to rebuild the trans/syncros with USDM parts? (VG30DET I assume)

Thanks!

[l0nestar]

You need to search man. There have been several threads about trans fluid. Everything internally should be nearly identical to a VG30DE (non turbo). With the exception of the input shaft and maybe something else. Andy (Booztd3) did a good write-up on it. It is long and detailed and well worth it.

[WhatsADSM]

You need to search man. There have been several threads about trans fluid. Everything internally should be nearly identical to a VG30DE (non turbo). With the exception of the input shaft and maybe something else. Andy (Booztd3) did a good write-up on it. It is long and detailed and well worth it.

I apologize, I must be using the wrong keywords in the searches or something.. I searched and came up with just a few results basically asking if the spec should be GL-4 or GL-5, but nothing specifically spelling out good results for weak syncros. I'll give it another shot with different keywords.

Thanks for the heads up on the Booztd3 post, I'll go find that one now.

[Bwana]

You need to run GL-4. Redline MT 90 is the way to go according to general consenses.

[l0nestar]

I'm running Napa (Valvoline) 90w gear oil (GL-4 rated) and don't have any complaints. There was a discussion about how much to use - I think 2.5q is correct - any parts store can look up the quantity - Use Z32 NA as ref. Use the nipple on the side of the trans and don't over-fill it.

[blurrbosi]

mt90 with lightweight shockproof... I made this concauction but it seems to be working beautifully.