Old Rotor Head

I replaced the trans fluid in my '99 MN6 last weekend with Royal Purple. The shifting has gotten stiffer, down shifting is almost impossible. If it effected the paper barriers are they gone and need replacing or will changing fluid help?

FKING1

I put Redline D4ATF, which is similar to RP, in my 00 M6 5 years ago and it continues to shift just fine.

burbleflyer

I put RP in my '00 six speed last year and it made shifting easier. I cured my morning reverse shift difficulties completly.

ETA: I did not use RP ATF, I used their manual trans stuff.

Oldvetter

I would change to Amsoil ATD or ATF and see. It immediately fixed my grinding 6th gear 1998 using Mobil 1 ATF when I changed fluid.

SUPERCRUZ

I think you need to get the RP ATF out and put in RP Synchromax, Redline D4 or Redline MTL, or Amsoil. I am running the Redline D4 product in my MN6. Good luck with it.

John Galt

If the paper barriers are gone, you are SOL. Changing fluid at this point will not help.

Still, I would try changing anyway to see if it helps, because it may be that the barriers are not gone.

jedblanks

I don't think your issue is RP ATF, I used it and RP rear end oil. Both have been fine for 1 year and 10,000 miles. This is in a 1997 MN6

striper

I hope you didn't use RP ATF. They make a specific fluid for manual trans cars that require ATF. It's called Synchromax. I have it in my car a couple of years and it shifts perfectly. I tried a couple of other brands and the RP was the smoothest.

rhneff

You might want to check out this thread:

http://forums.corvetteforum.com/show...26&forum_id=49

RP recommends both RP ATF and RP Synchromax for standard transmissions requiring a Dexron III type fluid, but suggests Syncromax offers higher performance.

That said, I couldn't find the thread but do recall some time ago reading one on the forum that said the friction material on the sychros used in early C5 transmissions was different than on later models but I can't recall what year it changed. It's possible the OP's 1999 model uses the older type material and could have been damaged by the fluid.

As another posted suggested, best action would be to drain the RP completely and re-fill with GM fluid to see if things get better. If the synchros have been damaged it won't help, but you might get lucky.

WKMCD

I run RP in my 98 transmission with great results.

Old Rotor Head

Thanks guy's. Switched back to Mobile1 and all is well. Looks like I used the wrong RP, RP AFT Max not Sync.

C66 Racing

These are the fluids to which Oldvetter is referring:
AMSOIL ATF
AMSOIL Torque-Drive Synthetic Transmission Fluid

I've been using the ATF in my 02 Z06 on the track for years without any issues.