C3 Shifter / Bracket

[Noel O.]

Seems as the mounting hole on top side of the mounting bracket on my 68 L89 has become badly stripped and the shifter has become effectively detached from the top of the bracket (the lower bolt still in place but lose). Do I need to replace the bracket or could I thread a nut on the other side of the bolt and tighten it up against a washer? The top bolt does have quite a bit of room to move around in the hole on the bracket (not sure what happened here). How difficukt is it to replace the bracket and remount the shifter?

Thanks in advance

[Joe L.]

Re: C3 Shifter / Bracket

Seems as the mounting hole on top side of the mounting bracket on my 68 L89 has become badly stripped and the shifter has become effectively detached from the top of the bracket (the lower bolt still in place but lose). Do I need to replace the bracket or could I thread a nut on the other side of the bolt and tighten it up against a washer? The top bolt does have quite a bit of room to move around in the hole on the bracket (not sure what happened here). How difficukt is it to replace the bracket and remount the shifter?

Thanks in advance

Noel-----


The shifter bracket has a weld nut attached to it for the through bolt that attaches the shifter. Apparently, that nut has become stripped. My guess would be that this happened because someone previously cross-threaded it OR it may have been left loose, in which case vibration may have destroyed the threads.

You can do as you suggest and just use a new nut "over" the existing nut. You may need to use a slightly longer bolt. The problem may be getting a wrench on that nut so that you can tighten the bolt. I feel pretty confident that's why GM used a weld nut in the first place.

Removing the bracket is really not too difficult. You need to first remove the linkage. Then, it's just a few more bolts and it's out. Then, you could replace the nut be cutting it off and welding on a new nut. The bracket is GM-discontinued, so you can't purchase a new one from GM and I don't think this bracket is reproduced. Three different brackets were used over the 68 to 79 period. However, all are functionally interchangeable and appear virtually the same. There should be plenty of these for sale in the used marketplace.

Two cautions:

1) Make sure you use very high quality, grade 8 bolts for BOTH of the shifter attachment points to the bracket. This is critical. Also, inspect the existing bolts for any signs of damage. Replace if ANY is discerned. The long bolt is the same as the long small block exhaust manifold bolts;

2) Make sure you don't exceed the recommended torque on the 2 bolts which fasten the support from the REAR and into the crossmember. These are self-tapping bolts that are tapped into the native material of the crossmember. Too much torque will strip them, for sure.

[Noel O.]

Re: C3 Shifter / Bracket

Noel-----


The shifter bracket has a weld nut attached to it for the through bolt that attaches the shifter. Apparently, that nut has become stripped. My guess would be that this happened because someone previously cross-threaded it OR it may have been left loose, in which case vibration may have destroyed the threads.

You can do as you suggest and just use a new nut "over" the existing nut. You may need to use a slightly longer bolt. The problem may be getting a wrench on that nut so that you can tighten the bolt. I feel pretty confident that's why GM used a weld nut in the first place.

Removing the bracket is really not too difficult. You need to first remove the linkage. Then, it's just a few more bolts and it's out. Then, you could replace the nut be cutting it off and welding on a new nut. The bracket is GM-discontinued, so you can't purchase a new one from GM and I don't think this bracket is reproduced. Three different brackets were used over the 68 to 79 period. However, all are functionally interchangeable and appear virtually the same. There should be plenty of these for sale in the used marketplace.

Two cautions:

1) Make sure you use very high quality, grade 8 bolts for BOTH of the shifter attachment points to the bracket. This is critical. Also, inspect the existing bolts for any signs of damage. Replace if ANY is discerned. The long bolt is the same as the long small block exhaust manifold bolts;

2) Make sure you don't exceed the recommended torque on the 2 bolts which fasten the support from the REAR and into the crossmember. These are self-tapping bolts that are tapped into the native material of the crossmember. Too much torque will strip them, for sure.

Thanks Joe

Actually, I was just outside and took another look at it and appears as if the nut is actually gone which would explain all the play in the hole. I think I can actually I see where the nut was welded to the bracket. Any idea what size what size nut this would be? Also, I cant see how I will be able to access the the bottom bolt of the shifter from inside the car to tighten it correctly once the top bolt has been threaded. There does not seem to enough clearance to get a wrench in to tighten once the shifter is aligned properly against the bracket.

I guees you could always cut out small areas on the transmission if it were really necessary fro access - this would be the elat favored outcome though.

Paragon sells the brackets (reconditioned origincal $135)

[Joe L.]

Re: C3 Shifter / Bracket

Thanks Joe

Actually, I was just outside and took another look at it and appears as if the nut is actually gone which would explain all the play in the hole. I think I can actually I see where the nut was welded to the bracket. Any idea what size what size nut this would be? Also, I cant see how I will be able to access the the bottom bolt of the shifter from inside the car to tighten it correctly once the top bolt has been threaded. There does not seem to enough clearance to get a wrench in to tighten once the shifter is aligned properly against the bracket.

I guees you could always cut out small areas on the transmission if it were really necessary fro access - this would be the elat favored outcome though.

Paragon sells the brackets (reconditioned origincal $135)

Noel-----

Both of the bolts attaching the shifter to the bracket are hard to get at and tighten. However, it can be done; I've done it many times. I don't recall if I got at them from below or above but my recollection is that it was from below. I would not modify the floorboard to provide better access. I KNOW that's not necessary.

The nut is a 3/8-16" thread size. My recollection is that it's a square nut, welded to the bracket. If you weld a nut to the existing bracket you have to be sure the nut is 100% perpendicular to the bracket surface. If it's "off", you'll never get the bolt into or through it.

[Noel O.]

Re: C3 Shifter / Bracket

Thanks again Joe.

What would you suggest as the best steps to get the shifter and bracket on and off the car (ie remove linkage from the shifter assembly, remove shifter, remove bracket etc). Any details, tricks or nuances would be greatly appreciated.

Thanks again,

Noel