Whosit

After installing the 4.10 if I don't start off right the car will jerk but I also hear a noise from the drive line somewhere. The sound is something as if you had bad U joints and rocked the drive shaft back and forth. It only does it if the car is jerking as a result of starting off wrong. I have almost gotten use to the 4:10 so I don;t screw up as much but wondering if the noise is normal? Checked everything underneath and it's all tight.

Thanks.

Whosit

Anyone?

825LTRGT

That seems to be normal at least that what Ford says. The clunk sound has to do more with driving technique than anything else. It took a while for me to not make the noise. If you preload the drive line and are not abrupt with it, it doesn't make the clunk sound. However there is a TSB on the clutch making noise.

FWIW, some of the Bullitt guys had a higher incedence of the clunk due to the 3.73s. Do a search on clunk and driveline noise and you'll see there are quite a few threads on it.

You may want to have your setup checked for proper pinion angle though. That could make it worse.

Shotokan1509

The 2 piece driveshaft is sloppy, a 1 pc aluminum seems to reduce it.

jlmounce

Right. There's a lot of slack in the driveline from the factory. Going to a lower gear which multiples your torque further and makes things a bit more touchy exacerbates that. Once you get your technique down with your new gears that should go away.

Whosit

Yeah I can take off without the noise but the is the odd time I mess up a bit and that's when I hear it. I might look into a one piece drive shaft as well. Is the free play in the shaft or the tranny or a bit of both?

jlmounce

It's everywhere in the drivetrain. The flywheel mates to the engine which has a clutch and pressure plate, that mates to the input shaft of the transmission which has 5 forward and 1 reverse gear that mates to a universal joint attached to a two piece drive shaft, which has another universal joint attached to a pinion flange, which connects to a pinion that drives a ring gear that sends power through a clutch system to two separate axles, all of which have a varying degree of tolerance and slack for free working operation.

See where I'm going with this?

These cars are mass produced by machines and humans for hundreds of thousands of people. To do so fluidly requires wider tolerances. Thus, you get slack in a drivetrain. TO get rid of all that slack you really would have to take the car to a shop have the whole thing disassembled and reassembled with tighter tolerances. Not exactly cost effective for a problem that really isn't a problem at all.

Shotokan1509

Yep, I'm also a 95%er, but that 5% really annoys me... tends to be over really rough road when starting from a stop, its hard to keep it from not jerking and clanking around, thats with 4.10's.

The DS will remove some play, and some rotating mass which means the car revs faster and picks up a tenth or two at the track.... downside is the cost of buying one.

TacoBill

I get wierd clunking sounds too if I don't give it enough gas when starting out. But, I attribute that to the 4.10's, 1-pc DS, Centerforce DF, and aluminum flywheel.