High rpm shifts - Transmission Forum

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High rpm shifts
Saturday, August 25, 2012 6:38 AM
I recently had the Isuzu 5speed rebuilt in my 99 Z24 before gettin the car together. After havin the car tuned and moving the rev limiter to 7k I discovered that the tranny would not shift past about 6500rpm. I use synchromesh tranny fluid and check it all the time to make sure it's full but if I rev to 7000rpm and try to up shift it just grinds and will not go into gear. Is there a different fluid I should be using and something that I should do the tranny? I read about people spinning 7k or better all the time but my tranny just won't have.

Re: High rpm shifts
Saturday, August 25, 2012 12:40 PM
Sounds like clutch drag...


Chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

Re: High rpm shifts
Saturday, August 25, 2012 5:53 PM
Like a slave cylinder issue?
Re: High rpm shifts
Sunday, August 26, 2012 8:35 AM
No. Clutch drag.

Short, you need a new clutch, may have cracked the disc, a plate bolt could be coming out... the "what if's " don't end.

its a isuzu trans.. that what? A half hour to get it out at with out a lift?

Don't over think, investigate.

I am assuming you did bleed the clutch out, and pumped the peddle back up, keeping the bottle full...


Chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

Re: High rpm shifts
Tuesday, August 28, 2012 9:54 AM
sounds like good ole isuzu syncro grind to me...



I choose the technology built for land speed records... not the technology built to save on emissions and gas mileage.
Re: High rpm shifts
Tuesday, August 28, 2012 12:31 PM
-Z Yaaaa- wrote:sounds like good ole isuzu syncro grind to me...


Solution to this? Lol or am I just gonna have to force it forever.

I'd like to upgrade clutches but money has become alittle tight for the rest of the year so it'll have to wait.
Re: High rpm shifts
Sunday, September 23, 2012 11:17 AM
No help here, just shift at 6500. LOL If you find out what's doing it let us know.
My limiter was raised but I never wait to shift at it, but you have cammed it or what ever and that's why you want to shift at that high RPM.
I shift to my torque/hp curve which is about 6000 ish that way the next gear drops in at high tq/hp range.
Re: High rpm shifts
Wednesday, September 26, 2012 10:48 AM
only fix is to rip apart the trans and replace the worn syncro rings, unfortunately.



I choose the technology built for land speed records... not the technology built to save on emissions and gas mileage.
Re: High rpm shifts
Wednesday, September 26, 2012 11:20 AM
I've been shifting at 6500 and it seems ok. I'm in the process of finding a spare tranny
Re: High rpm shifts
Tuesday, October 23, 2012 9:47 PM
Ethan Duke wrote:I've been shifting at 6500 and it seems ok. I'm in the process of finding a spare tranny


Just buy a new one http://www.ebay.com/itm/130726288914?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

I just bought one a few days ago, we'll see if it actually shows up this friday and how it works out.
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