Lash.

Mad4slalom

CCCUK Member
Hi all , i was reading that all vettes have or had from new a degree of drivetrain slack or lash as its called in the usa , And that GM dealers were told not to try to correct it under warranty as it was normal. I have noticed I can get a clunk here and there if i drive not thinking about it. How bad is yours and how normal is it or how much lash is normal and have you found a way to limit it or drive around it?
 

Oneball

CCCUK Member
There’s slack in all drivetrains. My rule of thumb is if you can feel it by turning a wheel it’s ok, if there’s a clunking noise when driving it’s not ok.
 

Roscobbc

Moderator
You'll find that a rumpity, rumpity cam will seeming amplify the any 'slack' in the drive train. I'veheard that addition of a late model 5/6 speed overdrive transmission can do the same thing with any 'slack' too.
 

langlj00

Busy user
Hi all , i was reading that all vettes have or had from new a degree of drivetrain slack or lash as its called in the usa , And that GM dealers were told not to try to correct it under warranty as it was normal. I have noticed I can get a clunk here and there if i drive not thinking about it. How bad is yours and how normal is it or how much lash is normal and have you found a way to limit it or drive around it?
Clunking is not normal.
I've had some for a while going from forward to reverse, although the perceived wisdom is that this is normally the rubber mount at the front of the Diff not doing it's job, in my case new UJs on the driveshaft cured the issue.
Just my 2p
 

Roscobbc

Moderator
Seem to recall many moons ago when I had a fairly hot 4 speed 428 Galaxie. It had a 3.25 rear axle. Being a 'full size' car weight distribution was far better than say, a Mustang of the day. So achieving a wheelspin was tricky. The simplest way was always to accelerate hard in first gear - back off on the gas pedal - re-apply power and the backlash in the drivetrain would sudden 'take-up' all the last in the system and break traction. Probably OK for a while on cars with live axles - perhaps not the sort of thing you'd want on the independant rear end of the Vette with its six UJ's and rather weak diff :oops:
 

Forrest Gump

CCCUK regional rep
Manual gearbox cars tend to be much harder on the drivetrain than an auto.
Diff front snubber mentioned above by langlj00 is a good shout, a worn out one will cause a “clonk”
 
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