Gearbox issues

AV8TOR · 04-15-2012, 07:26 AM

I have a stock 915 gearbox that will no longer shift into 3rd, 4th (or could be 1st and 2nd), 5th, or reverse.
It only moves in one plane. I am thinking bent shift forks??????????
I recall during my last few events it was getting hard to shift into reverse, but I don't recall that it was only shifting in one plane (This gearbox is in a race car that has been sitting for 5 years).
Any ideas??

Joe Bob · Joe Bob's Garage

Hows the coupler in the tunnel look?

AV8TOR · 04-15-2012, 11:45 AM

Coupler was tight, no issues.
Thanks, AV8TOR

tuchan · 04-15-2012, 05:04 PM

No shifting whilst car is idle or driving? Clutch operating ok? How is the shifter itself, is it sloppy at all?

Oil in gearbox?

Scott R · Scott R's Garage

With that particular problem I would check to see if the stubby end piece of the shift rod has come lose. It's just epoxied in and when it goes you get the issues like you describe.

MBruns · 04-15-2012, 06:06 PM

If all the bushings look OK, pull the shift pivot plate from the bottom of the box, they can pull the threads on the 3 stud fork and cause this

Mike Bruns JBRacing.com

AV8TOR · 04-16-2012, 04:51 AM

Thanks to all for responding........

kodioneill · kodioneill's Garage

Quote:

Originally Posted by MBruns

If all the bushings look OK, pull the shift pivot plate from the bottom of the box, they can pull the threads on the 3 stud fork and cause this

Mike Bruns JBRacing.com

+1 on this guy's advice.

kwikt 911 · kwikt 911's Garage

Happened to me...... the nuts backed off the stationary fork and then it was stuck in 3rd gear. Tightened the 3 nuts and Loctite solved the problem.

AV8TOR · 04-21-2012, 07:28 AM

Thanks to everyone who contributed....

MBruns · 04-21-2012, 02:54 PM

Did you fix it ?
Mike

AV8TOR · 04-22-2012, 04:55 AM

I have not been to my shop since Saturday the 14th. I will be going there first thing tomorrow
morning. This gearbox is my first project to get done on the car.
Cheers, Tom

AV8TOR · 04-22-2012, 06:12 PM

Mike, opened the pivot plate access, fork and nuts still attached firmly onto the plate. I tried
tightening up the clutch cable and working the clutch a bit, it would shift into first and second
but that was it (and then it was not easy to shift into either first or second). Track event
this weekend, so I think at this point I am going to pull engine and gearbox, pull locked diff from bad gearbox and then install locked diff in another 915/41 i have in the shop, reinstall, drive this weekend.
This car has a WEVO short shift, so I will pull the cover off of the tunnel just to make sure there is nothing jamming up the shift mechanism.
Thanks again, and Cheers, Tom/AV8TOR

AV8TOR · 04-23-2012, 05:33 AM

any other ideas?????????

AV8TOR · 04-24-2012, 06:14 PM

Pulled the gearbox off the motor, turns out the round spring behind the throw-out bearing
had split in half, and was bouncing around inside the bell housing. When I looked down inside the bell housing (before splitting the motor and gearbox) I could see the spring ring
lodged in the throw-out fork. There were scars from the ring bouncing around inside the bell
housing, and on the outside of the clutch. I replaced the spring ring, and reattached clutch. Suspension work to do before motor goes back in.