Vibration/Noise on decelerating after regear (1 Viewer)

[Fj moneypit]

just had my 80 regeared to 5.29 to upgrade to a size 37” tire. Still currently run 35” tires. After the regear everything seem to run smooth but noticed on the freeway that as soon as I decelerate I get a pretty loud virbrating noise. At first I thought maybe it’s from the driveshaft but now I’m thinking it’s the gearing. I read a little about possible pinion lash issue. Anyone have this problem? Like I said it only occurs on decel. As soon as I speed up it goes away.

Thanks

 

[mjeckell]

I had the same problem. I am running 529‘s as well with a 315 tire. At around 65 mph on deceleration how I get quite a bit of noise. I looked at my pinion angles at both the transfer case and the differential flanges and they were off about 3°. I Purchased adjustable upper control arms to get the angles aligned the same. There is no more vibration or noises at that speed anymore.

 

[nukegoat]

Decel whining is very possibly bad gear setup. @gearinstalls.com

 

[scottryana]

Who did the regear? It could also be that your driveshafts are now spinning much faster at the same speed. I would definitely lube the driveshafts and see if that helps.

 

[BILT4ME]

Also because your u-joints have been disturbed, they may be running in a new pattern so it COULD be u-joints. Otherwise, it's a bad gear setup.

 

[gearinstalls.com]

I had this happen to a local customer(letting off the gas resulted in a loud rumble).. Turns out the the driveshaft slipped apart and was pushed back together out of phase.
Now even if you get them back in phase there is still the possibilty of the balance being 180 degrees out. In that case, re-spline it another 180 degrees. The clue is do the zerks all line up along the driveshaft.

 

[inkpot]

Pinion angles won't change with a rehear. It happens when you do suspension lifts.

 

[mjeckell]

I understand that pinion angles don’t change with a regear but like someone mentions above your driveshaft is spinning much faster. 65 is more like 75mph and it’s possible that he never reached those speeds to hear it

 

[Fj moneypit]

I had this happen to a local customer(letting off the gas resulted in a loud rumble).. Turns out the the driveshaft slipped apart and was pushed back together out of phase.
Now even if you get them back in phase there is still the possibilty of the balance being 180 degrees out. In that case, re-spline it another 180 degrees. The clue is do the zerks all line up along the driveshaft.


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Thank everyone especially @gearinstalls.com for the pdf info and diagrams. This may be the problem. A friend told me he had the same problem and it was the driveshaft.

 

[icorradoi]

You ever get this resolved?

 

[richardlillard1]

Pinion angles won't change with a rehear. It happens when you do suspension lifts.

No, but the speed of rotation changes which can cause issues.

 

[LC492]

Thank everyone especially @gearinstalls.com for the pdf info and diagrams. This may be the problem. A friend told me he had the same problem and it was the driveshaft.

Hi @Fj moneypit, did you ever get this issue resolved? i just got my LC back and now also having this same exact issue.

 

[Fj moneypit]

Hi @Fj moneypit, did you ever get this issue resolved? i just got my LC back and now also having this same exact issue.

I think the solution was a double cardan driveshaft.