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Drone at certain speeds

W

wildrussian

NAXJA Forum User
Location
Tennessee
Alright guys I need help. I know this is XJ forum but my 05 KJ has 29 spline Chrysler 8.25 in the rear so I thought you all can help me out. Here is the problem: I added Rustys 2.5" lift to my KJ about a month ago and now I get a oscilating drone (no vibes only noise) between 45 and 53 mph only under load. When I let of the gas it goes away. I took it to the dealer and they told me it was the rear pinion and driveshaft angle and suggested I do something to change the anlge, they wouldn't do it because of the lift. I took it to another shop and they told me that the drone is coming from the rear end and it would cost another $500 to figure out what it is. I replaced the rear U joints but that didn't help. You guys have any ideas what it could be? Is it some bearing in the rear end or something?
 
Its more than likely you need a SYE kit,very common with the late model transfer case and the C8.25.
 
Noise like you describe is usually caused by the meshing of the ring and pinion gears. Since it didn't do it before the lift, maybe the lift puts the pinion in a bind when under load. RPE's suggestion of a SYE kit might help, or you might be able to lower the transfer case somehow by dropping the crossmember.....?
 
Take it on a gravel road where there's plenty of loose gravel but otherwise smooth and not washboarded (assuming you have experienced the "drone" on pavement). If the sound doesn't appear then it very well may be just tire noise that you experience at a certain speed. Such was the case after my lift as confirmed by my mechanic whom I consider quite competent.
 
Last edited:
Rod Knee said:
Take it on a gravel road where there's plenty of loose gravel but otherwise smooth and not washboarded (assuming you have experienced the "drone" on pavement). If the sound doesn't appear then it very well may be just tire noise that you experience at a certain speed. Such was the case after my lift as confirmed by my mechanic whom I consider quite competent.
Click to expand...

Took it to the tireshop and tire shop guy looked at it and drove it and said it was driveline related.
 
pull the diff cover (good chance to change fluid) and look for metal shavings. pull the rear drive shaft and see if there is any pinion play. leaking anything?
 
polar_jeep_04 said:
pull the diff cover (good chance to change fluid) and look for metal shavings. pull the rear drive shaft and see if there is any pinion play. leaking anything?
Click to expand...

That was my next move but I really don't know what to look for when I do take it off. Last time I did it before the lift I had bunch of shavings on the magnet but everything else looked good. Not leaking anything. How hard is it to measure the pinion angle and compare it to the factory specs?
 
Did you adjust the pinion when you did the lift?
 
'05 KJ...probably has a few miles on it, right? You lifted it and kept the stock driveshaft? Probably have the stock u-joints too?

Replace 'em. Now. U-joints aren't happy when they start operating in a phase different than the one they've been in for the last half-brazilian miles.

Jim www.yuccaman.com
 
Yucca-Man said:
'05 KJ...probably has a few miles on it, right? You lifted it and kept the stock driveshaft? Probably have the stock u-joints too?

Replace 'em. Now. U-joints aren't happy when they start operating in a phase different than the one they've been in for the last half-brazilian miles.

Jim www.yuccaman.com
Click to expand...

he said he did that. it was first thought as well
 
Yucca-Man said:
'05 KJ...probably has a few miles on it, right? You lifted it and kept the stock driveshaft? Probably have the stock u-joints too?

Replace 'em. Now. U-joints aren't happy when they start operating in a phase different than the one they've been in for the last half-brazilian miles.

Jim www.yuccaman.com
Click to expand...


And that's sayin' nothin about Bolivian or Peruvian miles.
 
Sorry for getting off topic but do you live in Chattanooga? I've only seen one lifted KJ around town and its black with about a 3 inch lift. Would that be you? If so, I would highly recommend you pay a visit to Kudlow's Axle and Driveline on Rossville Blvd. If anyone could figure out what's wrong with your Driveline/Axle, it would be them.
 
Yucca-Man said:
'05 KJ...probably has a few miles on it, right? You lifted it and kept the stock driveshaft? Probably have the stock u-joints too?

Replace 'em. Now. U-joints aren't happy when they start operating in a phase different than the one they've been in for the last half-brazilian miles.

Jim www.yuccaman.com
Click to expand...

only 40000 miles and I did change the u joints with no luck, and I do have stock driveshaft. I don't think anybody even makes and aftermarket one. Tom Woods might i guess but I would like to find out for sure what it is before spending a fortune on the shaft.
 
88XjLaredo said:
Sorry for getting off topic but do you live in Chattanooga? I've only seen one lifted KJ around town and its black with about a 3 inch lift. Would that be you? If so, I would highly recommend you pay a visit to Kudlow's Axle and Driveline on Rossville Blvd. If anyone could figure out what's wrong with your Driveline/Axle, it would be them.
Click to expand...

Im about 1 hour away from Chattanooga and haven't been there in a while so it might somebody else that you seen. And I really appreciate the name of the place, I might have to check them out. I found a place in Knoxville called Rock Your 4x4 they said they will look at it when I can drop it off. I would just like to get a general idea it could be and if I could fix it myself.
 
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