The 4th gear is really that weak?Originally Posted by Mikegotone'02
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10-01-2008
The 4th gear is really that weak?
10-01-2008
Bit of an exaggeration. You're more likely to get a lot of knock from the crazy high load at those speeds WOT in fourth gear than damage the transmission.
10-01-2008
not an exaggeration at all, i burned mine up on one pull trying to top my car out. It was like a clutch slowly slipping to its death. I had 3 gears for the longest time and still got 21mpg's on average when i used gasoline. It worked just fine before i did that and tranny man said i done toasted 4th gear when i was at wot. I don't make that much power, more than you yes, but not that much. I wouldn't chance it.
EDIT: For spelling errors.
10-01-2008
Raised line pressure in fourth (since the stock PCM was never programmed with that intention, hence its speed limiter) is usually the fix. Crams the clutches together harder at WOT and reduces slip. Several people have pushed their 3800s to the 150+ range with this method on a stock trans and its fine. Of course most of these are 04+ transmissions and they do have at the very least a stronger fourth hub shaft. Not sure if that has anything to do with it.
Just remember that fourth was never meant for that, though. It's your overdrive (for cruising). It works in multiplication instead of reduction like all the other gears, so that puts different types of forces on the carriers and gears. Luckily our hard parts are nearly identical to some more heavy duty trannies in GM's line up, but the clutches are what you would want to help out.
10-01-2008
informative thread, Mike you should make a seperate post with your rants
10-02-2008
Fred my rants contained the information needed for this person, thanks.
10-02-2008
cool, is it actually better to race with overdrive off?
10-02-2008
Not unless you plan on going above 120MPH. I forget exactly when the PCM will try to shift to 4th at WOT. It's different for different cars, due to different final drive ratios. There isn't a GP out there that has my final drive ratio, so my shift point wouldn't matter much to you guys.
10-02-2008
I just checked the Powrtuner for shift points and my GTP will shift into 4th at 130mph. I have gotten my GTP up to 145mph once, so I guess I've already shifted into 4th at WOT before with no adverse affects (knocks on wood).
10-02-2008
my name isn't Fred haha
10-02-2008
and my zzp pcm said it had the line pressure increased on the transmission, so would this fix that WOT 4th gear problem?
10-03-2008
I wouldn't go so far as to say it will fix this problem but it would certainly help prevent damage from occurring. I would still be cautious about going WOT into fourth since our trannys aren't the greatest anyway and it could all depend on the condition of the tranny too, which I would assume was the case for Mike. But anyway just for the record when I did that 145mph run I was running the standard ZZP tune.
10-03-2008
this is true, but it says you are from there, so that's all i have to go off of.
10-06-2008
A buddy of mine ran that size pulley with the same mods. He had FWI and no DP but later got the zzp 3'' Dp...You would want to get a tune but i would go for it. you'll want to eventually get TB spacer from zzp and 180 Tstat from zzp
10-06-2008
TB spacer? come on. no one can really be that dumb.
10-06-2008
ROFL
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