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Name this noise....

J

jmsull

NAXJA Forum User
Location
Chicago
1999, 4.0L, auto w/ np 242 about 85,000 mi

Any ideas why every time I shift between P, R and D I hear and feel a hard jolt. It sounds like the car is being put in gear on a steep incline, but it does it on flat road.
 
Check out your motor and tranny mounts as well as your drive shaft ujoints.
 
I just put in a d44 this weekend, might that have something to do with it, perhaps bad u-joints, I didn't replace them.
 
langer1 said:
Sounds like too much backlash on your new D44
Click to expand...

I am not too familar with backlash, what it is and how it would effect the drivetrain. A quick explanation would be appreciated.

I just had it rebuilt by a very reputiable gear shop. P.S. I also had them put in a Powertrax No-Slip. I assume this isn't the problem because both wheels are stationary when it makes this noise/jolt.

mack said:
well...what did you check so far??
Click to expand...

Nothing, I was looking for some specific suggestions before I take everything apart again.
 
jmsull said:
I am not too familar with backlash, what it is and how it would effect the drivetrain. A quick explanation would be appreciated.

I just had it rebuilt by a very reputiable gear shop. P.S. I also had them put in a Powertrax No-Slip. I assume this isn't the problem because both wheels are stationary when it makes this noise/jolt.



Nothing, I was looking for some specific suggestions before I take everything apart again.
Click to expand...
Backlash is the amount of clearance between the ring and pinion gears. I think what your hearing though is normal for the powertrax locker as it shifts from forward lock to reverse lock.
 
langer1 said:
Backlash is the amount of clearance between the ring and pinion gears. I think what your hearing though is normal for the powertrax locker as it shifts from forward lock to reverse lock.
Click to expand...

Ok, well thats a much better assessment than needing a new trans. Maybe I'll call Richmond and make sure thats what I'm hearing/feeling. Thanks.

Any other ideas, or seconding of this one would still be appreciated.
 
I have the same 'jolt', 'clunk' if you will, on my '00. I believe it's related to the slip-yoke, it feels like that's where it's coming from. I figured a trans fluid/filter change would do it, nope, didn't even soften it.

How do you 'check U-Joints'? Simply, crawling under the vehicle and grabbing the driveshaft and givin it a lil shake? Or is there a more to it that that?
 
i have that same clunk i always just thought it was normal although i noticed all the other vehicles i drove would change smoothly...i just thought it came in a package with the rough ride.Ive had a slip yoke elim and a new drive shaft installed too but it still does it.
 
Last edited:
I shall call it Bob.....yes Bob



I now have the same clunck/jolt. I thought it was from the lower gears that I installed when I did my axle swap. Just thought thats the way it "handled." I dont think that motor mounts would be the culprit when just shifting. So, jmsull, did you put in lower gears when you did the swap?
 
Bowzer said:
...curious thinking... torque converter?
Click to expand...
on all of them??? not likely. but what do i know, i drive 5 speed sticks.
 
My 00 does it too. It started right after I did the rear locker install. I tore the cover back off and had my wife take it from R to D. It looks like there is some movement between the Quikloc and the cross pin. Like the locker is just a tad bigger than the cross pin. My front Quikloc is really bad. It sounds like the whole front diff is blown. Same deal up front too. Cross pin smaller than the grooves for the locker. I was going to replace the front locker but a D30 locker is a PIA to change. I have Warn hubs so it is not all that bad unless I am driving with the hubs locked in. Mine have both been like this for over 2 years and nothing has gotten worse or broke.
 
To answers a question up above; I did not change gear ratio.

Just to update, it's been a little over a week since I put the D44 (w/ Noslip) in, and the noise/jolt seems to have calmed down. Maybe I'm getting used to it, but it seems better. I figure the Noslip is settling or breaking in or what ever.
 
It happened to me last week after I had gears and lockers installed and it happened on my friends ZJ when he put a rear locker in. You can actually see the driveshaft turn and then slam to a stop when it catches up to the locker
 
I know when you buy a Detroit Locker they actually tell you in the book its going to clunk more from gear to gear and will noticbly roll more when you put it in park and let off the brake...Its because you replace the spider gears with a mechinisem that has a lot more free play then spider gears have.
 
jmsull said:
To answers a question up above; I did not change gear ratio.

Just to update, it's been a little over a week since I put the D44 (w/ Noslip) in, and the noise/jolt seems to have calmed down. Maybe I'm getting used to it, but it seems better. I figure the Noslip is settling or breaking in or what ever.
Click to expand...

My no-slip does the same thing. Over time you will learn to shift R-N-D with a moment of pause, maybe with your foot off the brake, and its not as bad.. That moment in neutral to take the load off the locker one direction before putting it on the other direction makes a world of difference.
 
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