I've seemed to have problems with this tranny since I got the car (brand new).
Within the first few thousand miles when the car had just an airlid, downshifting from 6th or 5th to 3rd on the highway would cause grinding (unless I double clutched). I changed the shifter to the Pro 5.0 hoping that maybe it was because the shifter sucked so much, but it didn't help. I called my dealer to have it looked at and they told me I could bring it in in 3 weeks (which I told them was ridiculous). Shortly later I changed the rear gears from 3.42's to 4.10's and the problem disappeared (albeit the tranny was still a little more reluctant to go to 3rd then the other gears). Thinking it was ok for a while, I stopped worrying about it.

A couple months ago, when I started powershifting the tranny, I noticed I would hear a slight noise going into 3rd gear. After a few track runs, every so often I would get a grind and the car wouldn't go into 3rd (also noticed this granny shifting on the highway). I figured it was just that I had tried to shift too quick and let out the clutch too soon. However, since then, the car has popped out of 3rd a couple times when downshifting (I'd put in the clutch, put in 3rd, coast/decel for a short distance, let out clutch, tranny pop out of gear) and last night when shifting on the highway is grinded 3rd again.

Is this a problem that I'm causing with my shifting or does this sound like one of the many common problems to the t56 box in the f-bodies? Is there a way to solve this by changing the fluid or anything? I just want to make sure before I bring it in (which might have to be about a month, it's my daily driver). Plus I'm a little nervous about bringing it into the dealer with my mods on it.

Oh, forgot to add, the clutch is stock with stock hydrolics, stock trans/clutch fluid, plus I have the shift stops adjusted on the Pro 5.0.

Chris

 

remove the shifter stops and see if that helps.

 

Nope, the shifter stops are adjusted properly so that the handle is not touching the stop in gear (there is a small gap between the handle and the stop).

But just in case that isn't enough, I'll back the stops out a little more.

Chris

 

Sounds to me like a possible bent shift fork allowing it to pop out of gear.The bent fork will make the grind you hear because it won't allow the trans to get all the way into gear(3rd) thus you hears the syncros grind,or it pops out.
Had similar instance but with 6th,changed the fork and damaged syncros and no problems.

 

Dang, was hoping it wasn't internal. I'm hoping the dealer won't fight me on the warranty. At least I get a free rental car under the warranty if the car is there more then 24 hours....

Just in case they won't warranty it, how much is it normally to get a shift fork/synchros replaced (labor wise)?

Chris

 

*why I dont powershift* I am too scared

 

It sounds like a combination of three things actually: syncro's are bad on stock trannies; 3-4 gear shift fork is made out of almum (can't spell worth a ****). And last but not least is the hydros on our cars.

Solution:

1) have the dealership replace trannies under warranty and replace it again in a couple of months on hard racing

2) replace the syncro and shift fork - www.ddperformance.com . Cost a buck or two but mine has served me well since I had it re-built.

I have gone through like 4 trannies and am on my 5th.

Also, get the drill-out mod done (do a search if your not sure of what it is) and the McCleod adjustable master.

Good Luck

David