B & M shifter bushing problem
Thread Starter
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
B & M shifter bushing problem
This morning, I had problems hitting 3rd gear and finding 1st at the stop lights, so I guessed the B&M shifter mounting bolts had come loose.
Upon disassembly, I was right but what I did not expect was the rear mount B&M bushing was completely GONE!!!!
Upon removal of the shifter to fabricate a new bushing, I also discovered the front mounting ear was bent slight as a result the missing rear bushing and taking the full force of shifting.
The factory bolts and bushings are, in my opinion, just too small. The factory torx bolts also have a tendency to loosen. I am sure Loctite would help but there is simply not enough metal for long term reliability. Remember, there are only 2 relatively small mounting bolts that attach the thin cast aluminum OEM shifter frame to the torque tube.
I plan on fabricating reinforcing metal plates top and bottom to replace the B&M bushings and reinforce the OEM mounting points. Also, drill out the threads on the tabs welded to the torque tube and thread in a bigger bolt. This should stop this from happening again.
Anyone else have this problem?
Upon disassembly, I was right but what I did not expect was the rear mount B&M bushing was completely GONE!!!!
Upon removal of the shifter to fabricate a new bushing, I also discovered the front mounting ear was bent slight as a result the missing rear bushing and taking the full force of shifting.
The factory bolts and bushings are, in my opinion, just too small. The factory torx bolts also have a tendency to loosen. I am sure Loctite would help but there is simply not enough metal for long term reliability. Remember, there are only 2 relatively small mounting bolts that attach the thin cast aluminum OEM shifter frame to the torque tube.
I plan on fabricating reinforcing metal plates top and bottom to replace the B&M bushings and reinforce the OEM mounting points. Also, drill out the threads on the tabs welded to the torque tube and thread in a bigger bolt. This should stop this from happening again.
Anyone else have this problem?
Last edited by Mez; Sep 7, 2008 at 12:12 PM. Reason: correction
Safety Car
Joined: Dec 2007
Posts: 4,070
Likes: 162
From: Coralville Iowa
I've not had the problem since I don't have the B&M shifter. Let me be the first to ask: Have you considered changing to the MGW shifter? The mounting plate on that shifter is stout and the shifter is extremely precise and well built.
Thread Starter
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Perhaps I was not very clear. Its not anything from B&M that failed. The two torx bolts that came loose are the original GM bolts that attach the OE cast aluminum frame to the torque tube. The OE bolts were designed to be installed once perhaps and after reused, they tend to loosen up over time. Loctite would help but in my opinion, the factory aluminum bracket and bolts are just too small.
Thread Starter
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
All short throw shifters require more effort, however. I am very sure the problem is the type of bolts which they used and probably were not designed to be reused.
Burning Brakes
Joined: Nov 2004
Posts: 988
Likes: 4
From: Livermore CA
There is a rubber/plastic angled cap like bushing glued on the bottom of the shifter box, it locates in a long welded slot on the torque tube. This can fall off if the shifter box is removed. If it has fallen off too much load will be transferred to the two top torx screws and they can either loosen, break the oblong zinc washers or break the ears off the shifter box, also when the box comes loose it will loose alignment and cause the bushing and seal in the exit of the box to wear quickly.
Thread Starter
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
There is a rubber/plastic angled cap like bushing glued on the bottom of the shifter box, it locates in a long welded slot on the torque tube. This can fall off if the shifter box is removed. If it has fallen off too much load will be transferred to the two top torx screws and they can either loosen, break the oblong zinc washers or break the ears off the shifter box, also when the box comes loose it will loose alignment and cause the bushing and seal in the exit of the box to wear quickly.
This locates the bottom of the shifter box to the torque tube and keeps it from moving down, twisting, moving forward or rearward. But it won't prevent the shifter box from lifting up or from rocking front to back if either one of the torx mounting bolts comes loose.
Last edited by Mez; Sep 7, 2008 at 02:39 PM.
