Tranny problems

[Kevin Alexander]

About to get my 2nd tranny in the last year fixed. The first time I was on the track launching and my car launched and spun, I let out of it and got back into the throttle and it started wheel hopping. Popped out of 1st gear and from then on wouldn't stay in 1st or 2nd without holding it in gear. Ended up one of the shift forks had slipped and caused the issues. Got it fixed and basically was rolling along in a parking lot meeting up with some friends the day of my wedding for a cruise in to the place of my marriage. I was rolling about 5mph in 1st and my buddies were standing beside their vws nagging me on as I pulled up so I blipped the throttle real quick to kind of stretch the front end out and POP it went. Same issues as before, wouldn't stay in 1st hardly at all. I did manage to limp down the road and get married. Just had to start off in 2nd.
Again this time the shift fork has shifted and causing the issues again. My tranny builder is a really good friend of mine and he has been doing these things a while, does really good work and hasn't had many issues like this before. The first one he did for me held up to about 100+ passes with dot slicks before it let go.  He was showing my how the shift forks attach to the shaft they are on and I noticed that all that keeps them stationary is a little set screw that kind of pinches it to the shaft.
I can't see how the things ever stay put this way.
  Question is, is there any way to keep these little pain in the butts from shifting and causing these problems I am having?? Can you weld them in place or something? I didn't have a chance to ask my builder these questions yet so I figured I would ask some of you pros before I talk to him agian.

[Bruce Tweddle]

Is it a steel fork or brass?
I would ask what torque he's using on the fork's bolt.
I have seen one online set of instructions on how to rebuild a gearbox that quotes the wrong torque for the fork bolts.

[Kevin Alexander]

Steel. I will ask him. Whats the proper torque anyway? He mentioned to me today that on some of the drag trannys he has put a roll pin or something in the fork to keep it stationary. He is making everything good with my tranny so I wont owe anything to fix it. Think thats great of him. I told him I would pay to have the forks pinned if he thinks it will help.

[Ohio Tom (DdK)]

Loose or broken trans mounts.
It will hurt your box to pull it out of gear under load. This is exaclty what a broken or loose trans mount will do.

[Bruce Tweddle]

Steel. I will ask him. Whats the proper torque anyway? He mentioned to me today that on some of the drag trannys he has put a roll pin or something in the fork to keep it stationary.

I would never pin it.  It is totally not necessary.  (but if you do, make sure he drills a straight through hole, so on disassembly, it can be pushed out)

There are 3 bolts inside the gear carrier that all use an 11mm hex head.  Two are the forward shift fork clamp bolts, and one is for the reverse relay lever.  Some mechanics just assume they are all the same torque and tighten them to the spec for the reverse relay lever bolt, 14 ftlbs.  However, the reverse relay lever bolt is M7, while the fork bolts are M8, so they are supposed to be at 18 ftlbs.

The online instructions I mentioned above had them all at the same torque.

At 18 ftlbs on the clamp bolt, they don't move.  Maybe your fork got bent?

Was your gearbox built with a rebushed gear carrier?  Sloppy shift rod bores will also contribute to what you're seeing.

[Bruce Tweddle]

.... and it started wheel hopping. ...... so I blipped the throttle real quick to kind of stretch the front end out and POP it went.

Like Tom said.  Or sloppy suspension.  They are what's causing the wheel hop or the gearbox to move around.  The end effect is busted parts inside.  I would also expect your 1-2 slider and your 1st gear idler to be junk now.

[Kevin Alexander]

I did have the tranny solid mounted front and rear and I have a strap I made to go over the top of the trans about where the intermediate housing is as well. We will know more this weekend exactly what all has went wrong. Its just so weird how it broke this last time. I was rolling about 5mph in 1st and gave it maybe 1/4 throttle real quick. No hopping or anything. I have gave stock worn out 4.37 trannys more abuse than this with big motors and they held up decent.
Yes Bruce he built it this last time with a bushed carrier because the 1st trans had some serious slop in the carrier.
I think my next project is to figure out whats causing the wheel hop. The car use to not wheel hop when I had 205/70s on it and I had to have new tires and went with some 205/65 kummos and now I have a little wheel hop. I have a traction bar I made out of some real thick wall steel supporting the engine in the rear. (about twice as thick as those chinese ones) Have also replaced the torsion bar bushings with urethane ones and that seemed to fix the issue until I changed tire sizes.

[Bruce Tweddle]

Have you thought of adding a Kafer-Cup type bar?
What rear torsions?  Snubbers?

The rebushed gear carrier is good.  Did he reuse any of the 1-2 shifting parts in the rebuild?

[Kevin Alexander]

Bruce I am not sure if he reused anything. I do know he changed the carrier to a rebushed one. He did mention something about welding up and machining some shaft during the rebuild (i want to say the shaft the forks are on)
Car currently has the stock torsion bars that came in it in 1963 with stock snubbers, urethane t-bar bushings, solid mounts front and rear, strapped in the middle and I also have some limit straps to keep the tires from tucking when I let off at the 1/4mile or in hard turn.
I do plan to try some bus snubbers. My question with these is will they work in the stock bug snubber mount or will I need one from a bus?
I remember with my 69 vw I used to drag race with this same engine only had stock torsion bars and a set of coil over shocks. No traction bar or anything. That thing never wheel hopped once I put coil overs on it. I guess it stiffened the rear enough to keep things from bouncing. With stock oil shocks it was awful. Only problem is it lifted the rear end some. I thought about trying a set I have laying around on my 63 and see if it helps. Shouldn't have to worry about it lifting the car since the suspension can only move down about 1/4 inch before the limit straps take over.
What do you think about this or maybe a KYB gas adjust thats not as forgiving to sudden suspension movement like an oil shock?

[Dougy Dee]

Please tell us you are using a later model box and gear carrier and not the '63 unit...

[Kevin Alexander]

Yes I am using a 74 model gear carrier. We took a 74 IRS trans and made it a swing axle. Ended up the bolt in the shift fork had loosened. Caused it to get out of adjustment. Replaced shift fork and made sure everything was torqued properly.