Drive train "Clunk"
 

SRT 2005 64,000 Miles

SO, I've been chasing this issue for a long time now, basically there is a HUGE clunk/Bang feeling when the car goes anywhere from Park to Reverse, Drive to reverse, or Neutral to Reverse. (can slightly feel it when put into Drive)
I mean you can really feel it. Feels like someone Rear ends you every time you put the thing into reverse and everyone comments on it anytime they are in my car.

This problem has been always present since I bought the car a little over a year ago but now it seems like it is getting worse.

It also occurs if I Press the throttle hard then immediately let go. Or sometimes form decelerating off of high speed in a higher gear.

I have checked these forums very thoroughly and can't seem to find a problem related directly to mine.

What I have checked so far.
1.Trans Mount - Good, Replaced anyways... No fix
2. Both ends of the driveshaft Flex discs - Fine
3. Couldn't easily see the center support bearing, but don't see that causing this issue.

Grabbing the Driveshaft and moving it back and forth, it moves about 1/2 - 1" I'd guess and I can sort of replicate the sound by doing this. It sounds like it's coming from the trans itself.

Unsure how much free play is allowed in the driveshaft :confused:

Could be coming from the Diff? But usually if the ring gear an pinion are misaligned you have other problems I would think like whirring sound form the diff.

I don't have a lift so trying to look at everything under the car is PITA...

If anyone knows of anything else I should be checking I would greatly appreciate it. I dont want to actually break something important!!!

Also car drives totally fine otherwise :cool:

Thanks for your guys support! :D
-Darren

Re: Drive train "Clunk"
 

May be the preload on the diff pinion - lock parking brake and rotate driveshaft/see if diff is giving lots of play.

Lock in park - secure drive shaft - and then move each wheel on rear to see play is issue.

Call Rob at needswings for info on noise.

Woody:confused:

Re: Drive train "Clunk"
 

Motor mounts maybe ?

Re: Drive train "Clunk"
 

Re: Drive train "Clunk"
 

I only mentioned the motor mounts because I couldn't think of any thing else that goes clunk in the night.

Re: Drive train "Clunk"
 

Passenger motor mount is loaded under torque. Driver side is one under stress. Dont consider that is it.

There is some WINK in gear sets but should be less than 15 degrees and similar between wheels - tested with parking brake OFF please. Use parking brake to hold axle and see driveshaft motion.... Guess about 1 inch around shaft; motion or play.

Did u check fluid for -COLOR??? Honey no silver!!!! Woody

Re: Drive train "Clunk"
 

Passenger motor mount is loaded under torque. Driver side is one under stress. Dont consider that is it.<br /><br />There is some WINK in gear sets but should be less than 15 degrees and similar between wheels - tested with parking brake OFF please. Use parking brake to hold axle and see driveshaft motion.... Guess about 1 inch around shaft; motion or play.<br /><br />Did u check fluid for -COLOR??? Honey no silver!!!! Woody

Re: Drive train "Clunk"
 

Re: Drive train "Clunk"
 

As one of 300 million owners of the continent, in proper AMERICAN, I had said that the motor mount on the passenger side was LOADED under torque ( conditions ). Thus in compression its motion would be limited where as the driver side can raise (rear up ) several inches in a most threatening manner. LONG time ago I had strapped down the driver side with a SS cable to reduce the stress-load on the driver side.

The clunk is most likely play in the drive train, and left untreated may lead to failure of big pieces. 2 years ago on the way to carlisle I passed a vehicle full power at a century and the rear ring ate my pinion in a hostile manner. Clunks are bad. Woody:D

Re: Drive train "Clunk"
 

Numbers wrong again, 327 million in the US, which is part of the North American continent. You do not own the continent as Mexico and Canada are part of North America.
OK so I misinterpreted your words. We speak English not American. :p
If a DS support was broken and the engine was chained down the chain could make a clunk when the chain got taut.
I think some auto tranny’s can make clunks due to valve problems.

Re: Drive train "Clunk"
 

Actually we own both the northern and southern American continents and allow the squaters to share it.

We all know where the cold comes from in the winter, see photo. Enjoy Woody

:p:p:p:p:p:p South Park has it correct

Re: Drive train "Clunk"
 

Re: Drive train "Clunk"
 

I would get it up in the air and look at the center carrier bearing.
the bearing itself should be fine, but the problem is the rubber going out.
and if you can move the driveshaft easily 1/2" - 1"
should definitely check.
and would clunk every time you out in gear if out, because driveshaft was under nonload, then in gear and brake on, the driveshaft jolts in stress.

Jack stands, blocks and ramps.

I have put some 2x10's on 2 good railroad timbers and drove right on.
I have some 14" bridge timbers, I thought about cutting one in a wedge, and have some 14" tall and 14" long ramps.

I wanted lifts for along time.
we are looking at a house atm, has a 88x44 shop spilt into two areas all concrete already, wife said "in the automotive side you can get and put a 2 post lift there and a 4 post lift here"

​​​​​why YES I can :)

Re: Drive train "Clunk"
 

Re: Drive train "Clunk"
 

THere is a hex metric socket on the driverside lower part of diff.You can pop it and poke finger in to check the color. I believe there is a second one to drain it which is lower.

Diff is not limiting the rotation of the driveshaft IMO.

Seems like 15 degrees rotation on the driveshaft, seems excessive at first glance. Check oil and see if its silver. Should change the diff fluid for general principles, but Id bet the diff has either worn or has excessive gap - not enough preload on ring gear.

Good video. WOODY:confused:

Re: Drive train "Clunk"
 

Yes, Woody, the lower on is on the other side. I had to visit Harbor Freight again to purchase a set of BIG hex sockets to do this job.

Re: Drive train "Clunk"
 

Re: Drive train "Clunk"
 

I would guess it's the diff pinions rather than the Ring and Pinion. I don't know what these were equipped with but some other vehicles in this time period had diff pinions that were net formed (rolled to shape) rather than cut. They were softer and could deform when loaded aggressively. That only gets worse as the lash is increased. I agree with the earlier comment that if the primary drive gears were grossly out of position they would get noisy.

Re: Drive train "Clunk"
 

I can see regular spur gears cold formed but diff pinions are a different kettle of fish altogether.

Re: Drive train "Clunk"
 

Overview and Design of Near Net-Formed Spherical Involute Straight
Bevel Gears
First line in the report: "Near net-formed straight bevel gears are used extensively in the automotive industry today"

Here's the link.
http://ijme.us/cd_11/PDF/Paper%20161%20ENG%20107.pdf

This paper talks about all the positive aspects but early designs were not so successful.