F40 Issue treatment.

[Blackrider]

I want to start off by saying THIS IS NOT A CURE!

As some of you know I swapped out my tranny fluid with Royal Purple Max Gear 70W90 full synthetic, it’s their GL-4 replacement. Right off the bat I noticed smoother shifting but I still had the frequent grinding problem. After about 1000KM (600Miles) I’ve noticed that frequency of the grinding has reduced about 70% and the harshness of the grinding has also reduced. I'll continue to monitor it and let you know if it gets better/worse.

It was 40 dollars well spent, ideally I would like GM fix the heart of the problem but I don’t see that happening any time soon so I took it into my own hands. I would recommend anyone with a F40 shifting problems or not switch to a full synthetic.

[TLS2000]

All I can say bud is:

HowTo section is where I'd finish this one. I have done major engine work before on the Grand Am (as you know, since you helped me), but I have never touched a tranny before. Where's the drain plug/fill plug. How do you flush it?

[Blackrider]

All I can say bud is:

HowTo section is where I'd finish this one. I have done major engine work before on the Grand Am (as you know, since you helped me), but I have never touched a tranny before. Where's the drain plug/fill plug. How do you flush it?

I'll do it tomorrow lol

[TLS2000]

You'd better! I'll buy the synthetic fluid tomorrow (I'm gonna go with Mobil 1).

[Blackrider]

You'd better! I'll buy the synthetic fluid tomorrow (I'm gonna go with Mobil 1).

Remeber to ask for their GL-4 Replacment! it should be a 70W80 or 70W90.

HOW TO http://www.g6performance.com/forum/view ... 6769#46769

[G6cpM6]

so has anybody put in the GL-4 synthetic replacement and it made it worse? i changed the fluid on my '99 jeep 5 speed once because i just figured it was time and it was starting to get a little slip into some of the gears, a week after i changed the fluid (and it was the exact type of fluid recommended) i was in the shop having $1000 in tranny work done because the grinding got so bad.
Im just curious and i'd like to put the RP synthetic in my 6speed just for kicks but i dont want it to get worse.
also, you used Max Gear and not the Synchromax? I dont really understand what the difference is between them.

thanks

[ElecBlueG6GT]

Slippage usually is caused by the clutch, not the type of fluid you have. Once gears are meshed, they are meshed. I believe this fuild exchanged being posted is to help the gears mesh. IE...syncro's spinning better.

[G6cpM6]

sorry by 'slipping' i didnt mean the clutch i meant the synchros were not meshing the gears so i guess i shoulda said grinding. i guess i could just find some clean containers lyin around and put the stock fluid in there and if the synthetic doesnt work i could just put it back in...

[ElecBlueG6GT]

sorry by 'slipping' i didnt mean the clutch i meant the synchros were not meshing the gears so i guess i shoulda said grinding. i guess i could just find some clean containers lyin around and put the stock fluid in there and if the synthetic doesnt work i could just put it back in...

Don't put old back in. If you take it out, leave it out. It's not That expensive. Especially when you consider the cost of a rebuild.

[G6cpM6]

yeah good call. oh well i guess im gonna go for it and just see what happens.

[QuickCoupe]

GM Synchromesh Fluid

Has anyone tried GM Synchromesh Fluid? Is it an acceptable replacement for the 6MT?

[Granite6]

Re: F40 Issue treatment.

I know this is an old thread but I wanted to pass on some info that may be helpful.

Since the GM transmission is a synchromesh design (GM fluid is "synchromesh") the best RP product would be their Syncromax vs the gear lube. I believe the difference is the friction modifier "package".

I recently put this into our 2003 S-10 with phenominal results.
The synchronizers were starting to stick. Going from forward to reverse sometimes would not be able to get into gear. I would have to "double clutch" to get the sychros to align.
2nd to 3rd shift would also sometimes balk.

The Syncromax is expensive (I think around $18.00 per quart)

But the transmission shifts better than new now. Smooth gear changes, reduced effort, and no more synchro problems.

I have talked to multiple people who have used this on domestic and imports with similar results.

[pete123]

Re: F40 Issue treatment.

i just fixed the shifiting issue on my g6 gtp 6speed..i recently did gear oil..that didnt help much...then yesterday i checked my clutch fluid reservoir and noticed that the fluid in there was black as hell...bled the system and put new fluid and shifts smooth..no more harsh second and third!

[Neatong6er]

Re: F40 Issue treatment.

how do you bleed the clutch fluid? I need to do this...