C-Beam picture included - Does this look like signs of C-Beam movement or normal?

[Corvette95]

I am about to install C-Beam plates, look at this picture of the c beam as it is now, do the scratches indicate movement or maybe just from an old R/I although I have no reason to believe trans has been out before with the low mileage. Thanks

[secondchance]

Tough to tell looking at a pic. Does the shifter pop up when starting out in 1st?
My suggestion is to clean the thread and use a bit of Locktite when installing C beam plate. I believe correct torque is 40 lb-ft. Excessive torquing can distort tail shaft housing - not good.

[Dynomite]

Post 39 - C4 Beam Plates and Installation

As secondchance suggests........

e. Tighten support bolts at Carrier (Differential) to 80 Nm (59 lb-ft).
f. Tighten support bolts at Transmission to 50 Nm (37 lb-ft).
g. Do not go over the Bolt Torque on the Carrier and Transmission or you risk changing the Dimensions of the Carrier and Transmission Connectons.

[Corvette95]

I have C-Beam plates on the way, been posting in my other thread but not getting much response, I do have shifter movement, I am also half way through motor mount replacement.

[secondchance]

Originally Posted by Corvette95

I have C-Beam plates on the way, been posting in my other thread but not getting much response, I do have shifter movement, I am also half way through motor mount replacement.

If your shifter is jumping up by 1/4" or more, I suspect C beam bolts are loose. C beam plate and 40 lb-ft (37 to be exact like Cliff said) should cure that. Locktite is to be sure the bolts don't loosen up like I am dealing with.

[Corvette95]

The original problems was in third gear I can accelerate (normal, easy, hard doesn't matter) after getting out of the gas, the shifter tilts back, but when easing back on the throttle in third is pops out of gear, it's only got 29k miles, I have taken it apart, mounts look possibly cracked - but not awful, have it ready to jack up motor to remove mounts but replacements haven't arrived yet. I was thinking a combination of possible C-Beams being loose and worn motor mounts , emailed Bill B for braces, he's says syncro's.... I was planning to pull the trans and send to Bill, but I wonder if the C beam and mounts would fix (wishfully) the third gear issue? Hydraulics are good.

[Ccmano]

On the one hand I would be willing to bet that between the motor mounts and the c-beam movement your problem should be solved. On the other hand I wouldn't second guess Bill B, assuming he knew all the facts, and still recommends the rebuild. Bill knows his stuff.
H

[Dynomite]

Originally Posted by Ccmano

On the one hand I would be willing to bet that between the motor mounts and the c-beam movement your problem should be solved. On the other hand I wouldn't second guess Bill B, assuming he knew all the facts, and still recommends the rebuild. Bill knows his stuff.
H

Concur.......A Transmission Rebuild by Bill B (especially with short shifter) is operationally better than New Original Transmission

[Corvette95]

Originally Posted by Dynomite

Concur.......A Transmission Rebuild by Bill B (especially with short shifter) is operationally better than New Original Transmission

Not disputing that, BUT I have a TON of money on this 90 restore, if I can, get the transmission to OE operation, that be ideal right now with Covid and Christmas, 4K on a transmission upgrade needs to wait if possible, so I am torn between putting it together and taking a drive BUT I have more than the transmission underway since I had to take manifolds out to do motor mounts..tough decision. On the bright side, I had the car finished last week, even cleaned it up, test drive was great, engine smooth, no air leaks in all the new weatherstrips, A/C, all new brakes, engine mods all were perfect...thought I would be posting my before and after pictures this week.

[Paul Workman]

If there is any doubt about C-beam movement, once you pull one off for any reason, inspect the bolt holes. If they are not round, i.e., oval at all, then you will know whether or not they have been scrubbing during shifts.

Those C-beam plates are one of the best investments one can make for these cars, IMO. Not only do they cure the squirming issue, but they make installing and removal (for whatever reason) a breeze (especially if you have hands on the larger than the average woman's!)

Attached is a drawing I made which captures the recommended spacing dimensions contained in the FSM. I don't know how critical or precisely one has to align the tail shaft housing, but if you install it according to the FSM, then when you check it later you'll have a reference to compare with.

Anyway...this is what the book says (and Bill B recommended). The spacing "jigs" referenced (IIRC) came from Bill Boudreau, if I'm not mistaken:

.