Sponsored

Gear swap - Engine Whining

cthomas31

Well-Known Member
First Name
Caleb
Joined
Sep 22, 2020
Threads
9
Messages
56
Reaction score
50
Location
Ohio
Vehicle(s)
2024 JLU Sport S Manual Soft top
Hey guys,

I'm running 35s with 2.5 inch lift on my JLU sport and was losing my 7th and 8th gear on the highway so decided to switch to 4.56 gears. After I got the Jeep back from the shop, I noticed a "whining" noise at certain RPMs/speed. I put 500 miles on it and took it back to the shop so they could do the 500 mile inspection and change out the diff fluid. The shop said everything looked perfect and that the whine does not have anything to do with the new gears.

So here's my question. What is the whining noise I'm hearing? Here's some troubleshooting and information about the whining and when it occurs.

If I am in neutral and/or park, the whining noise does not happen (even if I hit the gas and raise RPMs)
When I'm in drive, the whining noise does not always occur. It only happens at specific speeds. For instance, if I'm going 45 mph in 8 gear there's no noise, but when I am going ~48mph I can hear the whining.

I just took a $2k mile roadtrip and had no issues with the Jeep other than hearing the noise at certain speeds.

Hopefully you guys can help diagnose. Any information is helpful!
Sponsored

 

Headbarcode

Well-Known Member
First Name
Mike
Joined
Aug 16, 2018
Threads
26
Messages
7,782
Reaction score
17,829
Location
LI, New York
Vehicle(s)
2019 JLUR Stingray 2.0 turbo
Vehicle Showcase
1
Hey guys,

I'm running 35s with 2.5 inch lift on my JLU sport and was losing my 7th and 8th gear on the highway so decided to switch to 4.56 gears. After I got the Jeep back from the shop, I noticed a "whining" noise at certain RPMs/speed. I put 500 miles on it and took it back to the shop so they could do the 500 mile inspection and change out the diff fluid. The shop said everything looked perfect and that the whine does not have anything to do with the new gears.

So here's my question. What is the whining noise I'm hearing? Here's some troubleshooting and information about the whining and when it occurs.

If I am in neutral and/or park, the whining noise does not happen (even if I hit the gas and raise RPMs)
When I'm in drive, the whining noise does not always occur. It only happens at specific speeds. For instance, if I'm going 45 mph in 8 gear there's no noise, but when I am going ~48mph I can hear the whining.

I just took a $2k mile roadtrip and had no issues with the Jeep other than hearing the noise at certain speeds.

Hopefully you guys can help diagnose. Any information is helpful!
First off, did you reprogram for the increased tire diameter. Thats one of the several pieces of data that the 8-speed auto uses to adjust its shift points. If that's off, so will the shift points, resulting in the loss of the higher gears and overall non optimal drive ability. I've got 38's, and reprogrammed with a tazer, and stock Rubi gears. Hits 8th all the time, and a regear isn't even on the radar.

Second, if the whining sound wasn't there before the gear swap, than its possible that the shimming wasn't done as accurate as it should've been. What you're hearing is the gear mesh. You should get a second reputable shops opinion.
 
OP
OP

cthomas31

Well-Known Member
First Name
Caleb
Joined
Sep 22, 2020
Threads
9
Messages
56
Reaction score
50
Location
Ohio
Vehicle(s)
2024 JLU Sport S Manual Soft top
First off, did you reprogram for the increased tire diameter. Thats one of the several pieces of data that the 8-speed auto uses to adjust its shift points. If that's off, so will the shift points, resulting in the loss of the higher gears and overall non optimal drive ability. I've got 38's, and reprogrammed with a tazer, and stock Rubi gears. Hits 8th all the time, and a regear isn't even on the radar.

Second, if the whining sound wasn't there before the gear swap, than its possible that the shimming wasn't done as accurate as it should've been. What you're hearing is the gear mesh. You should get a second reputable shops opinion.
Yeah I reprogrammed for the 35s but never hit 8th gear on the highway. May be because the Sport has 3.73 gears and the Rubi has 4.10s. Thanks for the comment. I will probably take it to another shop and get a second opinion.
 

Headbarcode

Well-Known Member
First Name
Mike
Joined
Aug 16, 2018
Threads
26
Messages
7,782
Reaction score
17,829
Location
LI, New York
Vehicle(s)
2019 JLUR Stingray 2.0 turbo
Vehicle Showcase
1
Yeah I reprogrammed for the 35s but never hit 8th gear on the highway. May be because the Sport has 3.73 gears and the Rubi has 4.10s. Thanks for the comment. I will probably take it to another shop and get a second opinion.
Did you program the actual diameter, or the size on the sidewall? The former is the way to go.

You should have 3.45 gears, unless you have the diesel. Yeah, I've got shorter gears to begin with, but I made a larger jump in size difference from factory.

But, its a moot point because you already did the swap. Other than the intermittent whine, how is the overall drive ability compared to before the 4.56's?
 

deserteagle56

Well-Known Member
Joined
Apr 1, 2020
Threads
3
Messages
190
Reaction score
457
Location
middle of Nevada
Vehicle(s)
Wrangler Rubicon
The whine you are hearing has EVERYTHING to do with the newly installed gears. Happened to me when my rig was regeared.
 

Sponsored

JimLee

Banned
Banned
Banned
First Name
Jim
Joined
Mar 29, 2019
Threads
12
Messages
3,465
Reaction score
16,519
Location
Too damn close to Death Valley
Vehicle(s)
'19 JLU
You can also reprogram the gearing in the computer, at least you can with the flashcal, i think this is just as important as tire size for the transmission if not more so.
 
OP
OP

cthomas31

Well-Known Member
First Name
Caleb
Joined
Sep 22, 2020
Threads
9
Messages
56
Reaction score
50
Location
Ohio
Vehicle(s)
2024 JLU Sport S Manual Soft top
The whine you are hearing has EVERYTHING to do with the newly installed gears. Happened to me when my rig was regeared.
What did you end up doing to fix the issue? I scheduled an appointment with my local dearlership to get a diagnosis and see if they can fix.
 

Paluss

Well-Known Member
Joined
Feb 15, 2018
Threads
59
Messages
696
Reaction score
688
Location
maryland
Vehicle(s)
2022 JLURD
it may be the gear type they used, straight cut gears naturally create a hell of a lot of noise; helical gears mesh together in small segments at a time while straight-cut teeth are in contact with each other fully and for a longer period of time which makes for a very distinctive whine.
 

Oldbear

Well-Known Member
First Name
Dwayne
Joined
Sep 1, 2020
Threads
14
Messages
461
Reaction score
530
Location
Bowling Green, Ky
Vehicle(s)
16 Ram 1500 Ecodiesel; 20 JL Sport S 2 door
If it wasn’t there before it’s gotta be the new gears. As noted, straight cuts are noisy, but I believe I’d get it checked but a competent mechanic. If the gears are not setup right they WILL whine ( and also wear much quicker than they should).
 
OP
OP

cthomas31

Well-Known Member
First Name
Caleb
Joined
Sep 22, 2020
Threads
9
Messages
56
Reaction score
50
Location
Ohio
Vehicle(s)
2024 JLU Sport S Manual Soft top
Did you program the actual diameter, or the size on the sidewall? The former is the way to go.

You should have 3.45 gears, unless you have the diesel. Yeah, I've got shorter gears to begin with, but I made a larger jump in size difference from factory.

But, its a moot point because you already did the swap. Other than the intermittent whine, how is the overall drive ability compared to before the 4.56's?
Yep I measured the actual diameter.
 

Sponsored

Paluss

Well-Known Member
Joined
Feb 15, 2018
Threads
59
Messages
696
Reaction score
688
Location
maryland
Vehicle(s)
2022 JLURD
If it wasn’t there before it’s gotta be the new gears. As noted, straight cuts are noisy, but I believe I’d get it checked but a competent mechanic. If the gears are not setup right they WILL whine ( and also wear much quicker than they should).
I agree, if the gears are meshed to close together that could cause the whine noise too. On the plus side straight cut gears are much stronger then helical gears...
 

aro

Well-Known Member
Joined
Jun 29, 2020
Threads
8
Messages
236
Reaction score
300
Location
SoCal
Vehicle(s)
2020 JLUR
The whining is definitely from the new gears. It's pretty rare in the Jeep world, but in the Tacoma world it's relatively common.

The mechanic that regeared my Tacoma warned me about it beforehand, but I was lucky and didn't get the whine. He's specialized in regearing all sorts of vehicles for many shops in SoCal, so he knows a thing or two about it.

The bad news: it's annoying and I am not aware of any fix
The good news: it's harmless

You should have it checked out anyway if you can, make sure it's not some obvious mechanical failure.
 

2Wheel-Lee

Well-Known Member
First Name
Lee
Joined
Oct 10, 2018
Threads
2
Messages
402
Reaction score
342
Location
Orange County, CA
Vehicle(s)
2020 JLUR, 2006 Dodge Ram 2500 CTD, 1986 Suzuki Samurai, 1975 Datsun 620
The shop is brushing you off for their poor workmanship. Simply looking at the gears, they won't see the cause of the whine. They screwed up the install.
Sponsored

 
 



Top