Help. As I was having the rebuilt tranny installed I found that one of the threads were stripped when bolting the u-joint straps to the rear end. Need ideas for repair. She's been parked long enough.... having.. withdrawal...sypmtoms...need torque... before it's too late!

 

The best way would be to replace the pinion yoke. I can't recall offhand if there's room enough that you could drill out the bolt hole and use a bolt and nut

Pete

 

replace the yoke, there isn't much room for a thread repair insert. i guess a heli coil would work but they aren't very good inserts. i don't think i'd use a nut unless it was a nyloc nut and i'd loctite it too.

 

Personally I love Heli-coils and have had good results whenever I've used them. The pinion yoke will run you about $90 from GM, or you could grab one from a junkyard, but most yokes I've seen used are galled on the pinion seal surface, and will begin to leak in short order, even with a new seal.

The key to making Heli-coils work properly is to make sure that the pilot hole is straight. I'd recommend pulling the yoke and doing this on a drill press. Then tap the hole, but do not run the tap all the way through back side of the yoke, or the insert will just roll right through the hole when you try to install it. You need to leave a "pinch" area so the insert will seat. Locktite the insert with the red stuff and run it in. Use a punch and hammer to break off the tang and you're good to go. The Helicoil kit will run you about $35, and you will need a drill bit that is usally an odd size, so figure on spending a couple extra bucks for this.

Either way, you will need to re-set the pinion bearing crush when you reinstall the yoke. The simplest way is to just shim the existing pre-load crush collar and then torque the pinion nut until you achieve the correct 5-7 in/lbs of preload. You could also replace the crush collar and start from scratch, but getting the collar to start crushing is a pain, and it's easy to go too far and have to start all over again with a new collar. You can start the crush in a press to make it easier to finish it on the car if you do elect to go this route.

 

i like the inserts that use a standard tap size and have the little tabs you hammer in. trouble is you need a lot of metal for them, a 1/4 thread needs a 1/2 tapped hole to get the insert in. i've never had any real problems with heli coils, it's just not what i'd call the best or what i prefer.

 

I'd replace the yoke if it was mine. I also have had excellent results with Heli-Coils, but what you have indicates severe mechanical failure (where some mechanic failed to do the job right), and it may be damaged in other ways such as other fornicated holes, being beaten on and bent, etc.

http://www.drivetrainspecialists.com...=28&cat=GM+7.5 You need the one for 3147X U-joints.