just had some 5.13's installed in my 05 rubicon unlimited (LJ). at 50mph a high pitch whine starts and continues to get higher in pitch as the speed increases. When I let of the gas pedal it goes away as the jeep slows, but is present from 45-40 while decelerating. Also the diff cover was very hot to the touch after a 10 mile drive. Any Ideas?

just had some 5.13's installed in my 05 rubicon unlimited (LJ). at 50mph a high pitch whine starts and continues to get higher in pitch as the speed increases. When I let of the gas pedal it goes away as the jeep slows, but is present from 45-40 while decelerating. Any Ideas?

Gear whine caused by incorrect setup or cheap gears?

Sounds like the gears arent set up correctly.

They were motive gears with master install kits. I purchased online and had installed locally. Going to call in the morning and see what they say. Any other thoughts?

diff fluid?

They said it is synthetic. But I am not sure what brand. It is a highly reputable shop and I have never heard a bad comment or complaint about the place. I just drove 15 miles on cruise control and can't even touch the rear diff cover it is that hot, is this a sign of a problem inside?

They said it is synthetic. But I am not sure what brand. It is a highly reputable shop and I have never heard a bad comment or complaint about the place. I just drove 15 miles on cruise control and can't even touch the rear diff cover it is that hot, is this a sign of a problem inside?

Synthetic diff fluid?

Might want to check out this thread (http://www.jeepforum.com/forum/showthread.php?t=649642).

Immediately after switching to 75-140w Royal Purple w/ Ford Friction Modifier in my Ford 150 it started to make this weird whine/grind noise and hasn't gone away. I have put over 10k miles on it since then and it still sounds the same. Are synthetics to blame?

How did you break them in?

Extremely hot after 15 minutes of normal driving down the road?

Something is not setup correctly and chances are it is the backlash. Not enough backlash means the gears don't have any room to expand for normal heat expansion and can cause problems and eventual failure.

Doesn't cost anything but the fluid to check.

[QUOTE=pyleit;10172613]I just drove 15 miles on cruise control ...QUOTE]

It's not generally a good idea to drive at constant speed like that until your gears have gotten their break in period overwith and you change the oil again and inspect...

Thanks for the replies. I just picked it up last night and have only driven 30 miles since I picked it up. I am taking it to them on Friday to have a listen and will not drive it until then. I just want to go in there with some better knowledge to discuss the noise/heat. Any other comments or suggestions would be appreciated.

Gears are breaking in.

Here is my suggestion to break in gears:
Drive at HWY speed for 15 miles.
Let it cool down
Drive for another 15 miles
Let it cool down
Drive for 500 miles with no load
replace oil and check wear patten and BL at that time
Gears should be good.

never use synthetic during initial break in.

Basically, Check set up and pattern to make sure all is good. If not, Go back to shop and demand they fix it.

EDIT: the whine is normal. I had a whine on mine at initial install. But I checked mine during oil change and all was perfect. To this day, all is grand

EDIT: the whine is normal.

I wouldn't say it's "normal". On some cheaper gear sets where they aren't finished as nicely they can be prone to gear noise. On most of the more expensive sets and OEM you should only get a gear whine if it's not set up properly. A few thousandths adjustment (about .001" in backlash) can change it.

Sounds like poor setup. You may get resistance from the shop that installed it due to the customer supplied parts, but they should take care of it if they are a respectable shop. Ask them to show you what they use to determine pinion depth and to measure backlash.

EDIT: the whine is normal. I had a whine on mine at initial install. But I checked mine during oil change and all was perfect.

They should not make any noise if manufactured and installed properly.

Well I just noticed a 3" pool of gear oil under the front right passenger side axle of the jeep. and my inner wheel and tire are covered in gear oil. I will be taking it in tomorrow for this and the whine. I will post the outcome. thanks again

Well the leak was a seal/guide gone sideways and the whine still remains. The shop says that is is the motive gears and they have to be swapped/warrantied out and that they are installed properly.

they just want another couple hundo to install new gears

He actually offered to do the warrantee/exchange and install at no charge. He feels that the sound is not something that can be fixed it must be replaced. he told me just to let him know when I can drop it by for a full day if that is the route i want to go.:) I think for now I am just going leave it as is.

He actually offered to do the warrantee/exchange and install at no charge. He feels that the sound is not something that can be fixed it must be replaced. he told me just to let him know when I can drop it by for a full day if that is the route i want to go.:) I think for now I am just going leave it as is.

If they are willing to replace it at no charge to you, why not take him up on it? He may not be so accommodating down the road if the gears grenade when you knew early on they had issues and did nothing to get it sorted out.....

Just my 2c from dealing with similar issues in the past....

If they are willing to replace it at no charge to you, why not take him up on it? He may not be so accommodating down the road if the gears grenade when you knew early on they had issues and did nothing to get it sorted out.....

Just my 2c from dealing with similar issues in the past....

No shit! Listen to this guy if the shop will take care of it/you do it because you may not get a second chance.

The diff housings being hot at first is usually normal. Just means there is preload on the pinion and carrier bearings. This will stop after awhile as long as they didn't put too much load on the bearings. Like someone said earlier, go for a ten minute drive, let it cool all of the way back down, go for a 15 minute drive, let it cool, 20 minute and so on. As far as the wine goes I think I would have them fix that. Probably improper set up on pinion depth, could be the gears are bad. Either way I would fix it. I always break them in with a non synthetic, then change the fluid after 500 miles. Has worked well for me!

The Diff housing is hot, does not mean shit. It's going to get hot. Gears don't whine if properly set up. So it's a bad set-up or bad gears. LET THEM fix it now!

Ok I will get it in next week. Thanks again