I'm going to be changing my Tranny Fluid soon and have been reading some posts regarding Mobil, Amsoil, Redline, etc. My boss's son is big into the import crowd and it seems GM Syncromesh is the preferred tranny fluid for them or at least him... Seems a little ironic to me but was wondering what you guys think of it for the C5. http://www.5speedtransmissions.com/gm_syncromesh.html

 

Amsoil ATF

 

after much research, i went with Red Line D4 ATF

 

Those using it seem to be impressed with the results. The only negative I have seen is there is a question on its effect (if there is any) on the non-metallic parts.

 

Stay a way from the ATF, the reason STF was developed was GM needed a manual trans fluid that flowed well at -40F and protected up to +300F and protected the gears, syncro's and bearings.
ATF will fall short in the bearing department!

 

ttt -

 

Oil is like religon here

But, I have heard very good things about the syncromesh over many years. Most Vette transmission gurus acknowledge it is good stuff.

You'll get the usual endorsements for the usual synthetics, but I have heard from several solid sources that there are materials in the early C5 6-speed transmissions (pre 2000?) that do not mix well with synthetic lubes.

Good luck,

 

I have a 2000 MN6 - didn't know the Tranny material was changed throughout the years???

 

I've tried Redline D4. I had a slight improvement in shift quality, but not as much as I expected. I then switched to Redline MTL. The tranny not only shifts easier, but I can actually put in reverse on the first attempt.
I couldn't do that with the D4 or the OEM fluid.
I have used MTL in my 5 speed in my '88 IROC-Z. 262,000 miles later it still works great.

 

Read the Sticky. It'll provide some of the better threads I've found about the topic.

 

Me too!! But, I run GM Syncro in my 04 Mustang Cobra. Both work well.
Fred K.

 

Any syn ATF (Mobile1, Amsoil, Redline etc.) will improve shifting ease and trans life.

 

Yep, I run Synchromesh and love it...

 

I have used it for along time in all my GM cars to include my vette. i have also changed out a lot of other vettes to this fluid and everyone has really liked the results, much smoother shifts.

 

I just had the fluid put in my 00 Vert and it is amazing the difference, it's like a hot knife through butta. Xtreme Motorsports in AZ recommended it over the Redline, that they also sell, and I couldn't recommend it more highly.

 

The mechanic told me that I will be really happy with Synchromesh. He said I will notice that there will be less tranny noise and smoother shifts. He also said that his experience has been that when people change to Red Line, Royal Purple, etc. they do not notice a difference. He stated that I will notice a difference with Synchromesh. Since it is not Dexron III, I contacted some Tremec rebuilders (Google) for their opinions. All except one preferred Synchromesh to anything else on the market. The other rebuilder recommended Dexron III fluid. I had the fluid changed to Synchromesh. The tranny was much quiter and after about 10minutes of driving, the shifter just slipped into each gear like butter (USDA AAA, of course!). My prior cars took 75W90 gear lube in the transmission. Putting AFT in a manual is still "new" to me. That's been my experience with Synchromesh. Also, I read that Synchromesh will not harm any parts in your transmission..........I tried to do as much research as I could...I was was leary of putting in the fluid. The fluid was developed by Pennzoil specifically for GM transmissions; it is a partial synthetic fluid. From what I have read, many Mustang and Honda owners swear by Synchromesh.