Whine under mild acceleration

97TJNM

97TJNM

High Desert Redneck
Supporting Member
Joined
Oct 24, 2021
Messages
840
Location
Los Alamos, NM
Hey all! So, I just did an axle swap with 4.88 gears, 4 inch lift, new steering linkage, new TW driveshafts, and SS SYE. I also put some really worn out 33's on it I picked up for cheap. Obviously I'm getting some road noise from the clapped-out tires, but I am also getting a weird whine that only occurs during mild acceleration.

The noise is loudest when just barely pressing the gas. It is not present when coasting or decelerating, and quiets down the more gas you give it, until it completely goes away when giving it about half the pedal.

The gears looked decent in the axles u swapped in, but the were set up a little shallow. The noise seems to be coming from the front half of the vehicle, but I can't pinpoint it while driving.

Video below. Could this be pinion angle? Gears? Driveshaft? Noise starts at about the 4 second mark.

Video

I got the vehicle up to 68mph, and speed doesn't affect the sound, just acceleration. No vibrations at all. Could it just be the clapped out tires? I'm saving for new wheels and tires, and will be purchasing them in early July.

Thanks for any insights.
 
A whine on acceleration usually means pinion bearings. Especially with the fact that you just replaced the axle housing. Was the housing just rebuilt?
 
Andy-WhiteTJ said:
A whine on acceleration usually means pinion bearings. Especially with the fact that you just replaced the axle housing. Was the housing just rebuilt?
Click to expand...

No, I got them from a guy who had swapped in 1 tons. And to be honest, that seems like a good assessment. I feel like it's coming from near the front end.
 
Tell us more?

You bought what, used axles...Dana 30/35?...in 4.88, installed them and you're getting a whine?

Have you dropped the diff cover and inspected the gears? Maybe even run a pattern? Check pinion play?

-Mac
 
macleanflood said:
Tell us more?

You bought what, used axles...Dana 30/35?...in 4.88, installed them and you're getting a whine?

Have you dropped the diff cover and inspected the gears? Maybe even run a pattern? Check pinion play?

-Mac
Click to expand...

Hi Mac, appreciate the response.

Bought used axles Dana 44 rear 30 front. 4.88 gears, air locker in rear, had shop install axles. They have been on for about a year but has always been just an off road toy that never really saw 45 mph to hear the whine. Now going to begin to daily in near future. The whine begins around 40 and gets louder with speeed and is really bad when maintaining speed when foot is barely in the pedal.

I looked at gears with a mechanic friend and they looked good before installing. I do a lot do work on my jeep but my knowledge of gears is 0. Trying to find a shop around me to look at them is difficult as well.
 
trevino33 said:
Any update on what this ended up being. Literally exact same situation similar sound. Axle swap 4.88
Click to expand...

So, mine is definitely gear whine from poorly set up gears. That said, I ran a pattern on them, and they aren't horribly set up, just bad enough to get gear whine. If I remember correctly they were a bit shallow, and the pattern was more towards the heel rather than being perfectly centered.

The conclusion I came to was this: I have a stock Rubicon locker in the front, that I'd eventually like to replace with an ARB. I got the axles for $2500, so not too expensive all things considered. I had depleted my jeep funds at the time. So I decided to run them until something breaks, then get a new air locker and a new ring and pinion. I've had about 10k trouble free miles since the axle swap, many of those miles (probably in the 2-3k range) at highway speeds. Overall, I'm ok with my choice so far. No issues, except for the whine. I just turn my stereo up.🤣
 
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