IroczFan

I have a 86 Iroc with a 383 700r4 and a recently rebuilt rear end with a detriot locker... as soon as I rebuilt the rear end the car started wheel hoping on hard launches and burnouts maybe a month later I started feeling a slight clunk or something moving now when I get on and off the gas.. its really bad... I replaced the trans mount new bolt that go threw the tourqe arm / rear end and the clam shell mount on the trans and havent noticed a change it.. when you jack the car up and put it in gear and get on and off the gas you can hear/feel it in the trans but not sure if its in the rearend and just running threw the driveline. .. anyone got any ideas???

BOTTLEDZ28

iTrader: (9)

U joints, LCA bushings, really loose pinion nut,

skinny z

The points mentioned above are a good place to start.
Next time you have the car up on stands, check too see how much you can rotate a tire before the driveshaft moves. Sounds like excessive backlash in the ring and pinion. Having just had the rear end rebuilt and then this issue pops up kind of points to something potentially going wrong that rebuild. Hope not but just throwing that out there.
The wheel hop could have beat the crap out of any number of driveline components as well. Torque arm mount on the differential, and as mentioned, the LCAs, u-joints, etc.

big gear head

A Detroit Locker has much more clearance in it than most other differentials. It's not going to act the same when you jack up the car and start turning the wheels. It seems to me that something in the rear suspension is broke. Check the torque arm for cracks and go over everything.

IroczFan

I almost think it has to be in the rear end because the car is sittin on jackstands you can hear the clunk from the rear end all the way up to the trans... I would think scince the suspension isnt being used when jacked up it wouldt be that.. could be wrong

BOTTLEDZ28

iTrader: (9)

Pull the cover off the rear and take a peek inside with a flashlight. Have someone VERY CAREFULLY put the car into drive as you watch and listen inside the rear. Make sure the car is safely secured on stands AND you have safety glasses on. There will still be a little gear oil on the ring gear that will sling off of it if you let the rear wheels turn. Look for any play between the ring gear and pinion gear. Look for play at the yoke as well and inspect the gear oil as it comes out of the rear when you pull the cover.

skinny z

Just put it on jackstands and rotate one tire observing the driveshaft. What's the big deal? If the tire rotates a half a revolution before the driveshaft catches up, Detroit Locker or otherwise, then you've got something to go. Yes, no, maybe so?
Then you can pull the cover or go deeper into what's up.
If the driveshaft follows closely to the turning of the wheels, then you might want to check elsewhere or follow up on what Big Gear Head has to say.
Seems to me you've had it on stands already....after that it'll take you 30 seconds.
Maybe you'll see a universal joint that's beat or the u-joint/pinion straps are smoked.

TTOP350

iTrader: (8)

Detroit locker says it all. Loud, bangs and a LOT of play in them. Huge noises. On and off the throttle will thrust the car left or right but you'll never know which way.

tom86iroc

iTrader: (1)

I have one in my car people think there's something broken in the car lol very common with a detroit locker

big gear head

Yea, I have one in my '69 Camaro and one in both of my 4X4 S10 trucks. People are always telling me that I have a bad U joint, or something must be broke in my rear end.

IroczFan

The car didt start doin this until 6-8 weeks after the detriot locker was put it... the car is on stands ill have to see how long it take the driveshaft to turn as I spin the tire

IroczFan

Doesnt seem to be any big play when you turn the tire and driveshaft turning

skinny z

Is the play such that there seems to be an excessive amount of backlash? You say there's no "big play" so it may be that everything is OK with the ring and pinion. Then again, how much is "big play"?
I realize that little test isn't the most scientific (and the effort you're putting into is nothing like the torque applied by the engine) however if you had discovered considerable movement between the two (tire and driveshaft) then you would have something to go on.
With my car up on stands I can move the wheel back and forth and sort of "feel" the amount of backlash there is and that amount is very little. If I try and rotate the driveshaft by hand, it's very little rotation before I can feel the take up in the clearances. It also gives me good look at the u-joint and straps. And seeing as mine is also relatively fresh, I can assume that all is OK.
I was throwing that idea out there as a way of eliminating (or reducing ) the possibilities of where the noise is coming from.
As it's been pointed out, there are still a lot of places to look.