I just picked up an ITR. It came with a short shifter, unknown which model. It also has a exedy oem replacement clutch kit. For some reason I can't get into reverse. It really don't want to go in. All the other gears are fine. It does have high rpm 3rd and 5th grinds. Any suggestions or help would help. Thanks.

 

The grinding 5th gear is a good clue since it shares it's Synchro slider hub with Reverse. I assume you tried shifting into 3rd or 4th gear before attempting Reverse. Rebuilding the transmission sounds like a good idea if you already have issues with shifting. Replace all bearings in the case, synchro sleeves and hubs as needed as well as any individual gears ( 3rd mainshaft perhaps) and double check the shift selector mechanism isn't bent. That should make for a very smooth shifting transmisssion. At a minimum go for the bearings and sliders and check that selector mechanism.

 

I think he's trying to troubleshoot the trans while it's still on the car. Are you able to shift into reverse with the engine off, clutch in/out? You probably tried that already but it's worth ensuring. Are you familiar with the procedure of going back to neutral, let off clutch, press clutch in?

One of the simplest things you can do right now is to get under the car and manipulate the shift linkage to get it into reverse. Odds are it won't help much, but it'll at least eliminate the aftermarket shifter and shifter bushings from your troubleshooting (probably the mounts too).

Other things to consider:
- Drain trans fluid, look for metal shavings (there's already a magnet in there so you're likely to not get anything noticeable. Refill with Honda MTF, and try again.
- Inspect reverse switch. Is it possible for it to seize and block the movement of the fork by any chance? Probably not, the shift linkage would let you overcome that, but if it were me I'd eliminate all the small things before dropping the trans to look at the clutch + dissassembly of trans.

Fact is, when the trans goes in every gear but reverse at all, the cause is typically a bent shift fork. The part is pretty cheap, the labor to replace it is far from it.

 

I feel OP's pain for the grind in high RPM's I just got this tranny recently with this caR. And the tranny has similar issues -in the grind in high RPM'S in 3rd to 4th but the reverse issue is good on mine good luck OP hope its just a bent shift fork as others have stated. But since your still gonna have to split the case and take apart u might want to fix all problems not be cheap .since your gonna be in there or at least in my case I'll be replacing all bearings as well to since its split open along with any other things that look worn .Cause I know I dont want to have to do it again on the same tranny for miles to come if at all again . Another thing if you don't know how to break down the tranny and change out the shift fork and gears ECT. it will cost some $ as quick99si said unless u got a good buddy you can trust to do the work properly..
any way good luck bud .