borrone821

iTrader: (3)

Hey guys,
Random question. I had an aluminum driveshaft lengthened to fit into my 69 GTO. T56 going to a stock GTO rear. The question is, how did you guys install the driveshaft?
Are you supposed to have enough play where you can engage the spline in the trans completely and have about a half inch between driveshaft and rear yoke, then put the U-joint in, and slide it back the half inch or whatever it is?

Or do you have to pull the rear end back a bit to fit the u-joint on, then rebolt it up?

I guess the real question is, how much play are you supposed to have on a driveshaft front to back?

Sorry if this is a stupid question, but I've never done this before
Thanks
jim

newschool72

iTrader: (12)

about .600 is about minimum, .750 is ideal and 1.00 is ok. it give the suspension room to move, while giving enough spline contact on the yoke.

borrone821

iTrader: (3)

Thanks Newschool... much appreciated. So I want about 3/4" of play? So I should be able to slide the driveshaft in completely and the U-joint should clear the yoke on the rear end without moving either the trans or rear so I can then just bolt it in?

lizeec

iTrader: (57)

I think Newschool is referring to the slip yoke at the end of the driveshaft that goes into the transmission you want it to be about 3/4 of an inch before bottoming out on the transmission output shaft or seal area, that is with the other end fully seated in to your differential yoke. In your original post are you sure you had your driveshaft tube LENGTHENED?? I know it's possible, but highly not recommended.

Mike52

iTrader: (1)

Yes, that's correct.

Bob@BruteSpeed

iTrader: (16)

Keep in mind you want the rear tires in a loaded position when you check how much driveshaft travel you have. I get a lot of calls from people who have the rear end dangling down who can't get the driveshaft to fit back in. Bob

borrone821

iTrader: (3)

Thanks for the input guys. I'll have to check out how much play I have.
With jacks on the rear end, I couldn't fit the driveshaft in... I had to back the rear end up a tiny bit to get it to bolt on, and now everything fits fine and the rear tires spin pretty freely, but I'll check how much play I have.
And yeah, I got my driveshaft lengthened by about 10 inches. The guys at brookline driveshaft explained to me the risks of getting it lengthened, but since I wont' be running over 400rwhp, they said I'll be fine.