Topic: Whine coming from the new gears; opinions?

[jfrabat]

OK, so I got the new gears (4.88) installed along with ARB lockers and alloy axles.  But now there is a whine when accelarating from 35 to 40 mph.  It only does it at this speed, and i have only driven about 20 miles so far.  Is this normal, and if so, will it eventually go away?

[oldjeep]

Does it go away when you let off the gas?
Have you rechecked the gear lube, and what kind of gear lube did you use?

What is the top speed you were you going in those 20 miles? - gear break in is important.

[Jeffy]

If you just had them installed, take it back.  They should have test drove it, but I'm thinking they didn't bother.

[jfrabat]

Does it go away when you let off the gas?
Have you rechecked the gear lube, and what kind of gear lube did you use?

What is the top speed you were you going in those 20 miles? - gear break in is important.

Kept it under 45mph the entire way as instructed.  And yes, the whine goes away when I get off the gas; it's only showing when under load.  I dont know what lube they put in, but I am arranging to take it back (at least these guys warranty their work!).

If you just had them installed, take it back.  They should have test drove it, but I'm thinking they didn't bother.

I am thinking the same thing...

[aw12345]

Also depends on the brand of the gears some whine, it says so right on their website. If they used spicer or yukon gears it should be quiet from the get go take it back and have them re do it

[oldjeep]

Noise that stops when you let off the gas can also be a bearing, or you might want to check your pinion nut and make sure it hasn't come loose.

[aw12345]

Bad or loose pinion bearings will make noise opposite from gear noise I.E it gets worse when coasting but diminishes under load. If all was set up right the diffs should be quiet.

[Bounty Hunter]

What break-in procedure did you follow?

[oldjeep]

Bad or loose pinion bearings will make noise opposite from gear noise I.E it gets worse when coasting but diminishes under load. If all was set up right the diffs should be quiet.

Depends.  The inner pinion bearing will make more noise under power when it goes bad, the outter will make more noise on coast.

[jfrabat]

Also depends on the brand of the gears some whine, it says so right on their website. If they used spicer or yukon gears it should be quiet from the get go take it back and have them re do it

It's Genuine Gear (G2) suppossedly, but I have to reconfirm that...

Also depends on the brand of the gears some whine, it says so right on their website. If they used spicer or yukon gears it should be quiet from the get go take it back and have them re do it

Well, the noise goes away when I let off the gas; it's the more load the jeep is in, the more noise. 

Bad or loose pinion bearings will make noise opposite from gear noise I.E it gets worse when coasting but diminishes under load. If all was set up right the diffs should be quiet.

Noise that stops when you let off the gas can also be a bearing, or you might want to check your pinion nut and make sure it hasn't come loose.

The parts list included a master overhaul kit, which comes with Timken Bearings, National seals, complete shim kit, crush sleeve (if Applicable), ring gear bolts, cover gasket and gear marking compound, so bearings should be new as well...

What break-in procedure did you follow?

The guys told me that they had done the basic break in (with the Jerep in gear both forward and reverse while up on the stand) and then that I had to drive 15 to 20 miles while keeping it under 40 mph and then let cool completely.

I drove 20 miles home (not using the highway) at 40 mph most of the way, and left it there while I went on a business trip (for a week).  Today, I took it out for another 15 miles under 40 mph and will let it sit unitl tomorrow.  I will  call them tomorrow to pick the Jeep up (they have to move the swtiches from the lockers anyway because they did a real poor job of placement).

In any case, I still think the best solution is to have them check their own work.  I mean, this work is under warranty, so I can bug them as much as I feel like it until it is up to my standards, and I think I will just do that.  But thanks to all for the replies!

[Bounty Hunter]

Your two short drives with cooling period in between is what I would have done to break them in, nothing wrong there.  Let us know what they find.

[jfrabat]

I called the shop, and will be dropping the Jeep off the week after next (since I will be out of town then).  Next week I will mostly be out of town (depending on the hurricane), but I dont have time to drop the Jeep off (plus, there is a hurricane coming, so I might need the Jeep afterwards).

Your two short drives with cooling period in between is what I would have done to break them in, nothing wrong there.  Let us know what they find.

As for the drives, I just realized that both distance and speed were lower than I estimated, because the speedo gear was off.  But still, the drives should have been about 15 miles for the first, and 10 for the second at speeds of less than 40mph, which should be enough anyway.

Since I was feeling some vibration when driving at speeds (65~70mph) as well, I decided to take out the front drive shaft , as it is my understanding that on YJ's it is not balanced (I'll have it balanced, but have not gotten around to it yet), and I thought that was the source of the vibration, but I was wrong, as the vibration is still there, so it must be something on the front axle (I know it is the front axle because I can feel the vibration through the steering wheel).  The vibration is really not that bad (it is very slight), but you can defenetly feel it at speeds above 65 mph (you cannot feel it below that).

However, while under the Jeep, I noticed 3 other things that worry me a little, and I want to ask you guys for your opinion:

1. There was a small leak of fluid on the steering knuckles, so it seems that they did not install the axle correctly; is this something I should worry about for the next week while I take the Jeep back?  I drive about 20 miles per weekday and none on the weekend (at least until I get the Jeep fixed)...

2. I noticed a very slight fluid leak from the TC (I think it is comiung from the fill hole, but I am not sure; I will check the torque on the plug tomorrow, as I cant today).  Could the front axle rotating all the time cause any issues in the TC?  I know the stock YJ's axle does not rotate if not in 4WD, but with the alloy axle, since I did away with the axle disconnect, the axle now rotates all the time.  But IIRC, TJ's use the same NV231 and have axles that rotate all the time, right?

3. Nothing to do with the work done, but I also noticed some oil around the bell housing; putting 2 and 2 together, in the mornings, after the Jeep has been sitting for some time, I can feel the clutch slip for the first couple of time I get in gear (2 or 3 times).  Does this mean that I have a leak on the seal, and if so, do I need to take down the tranny to fix it?

Felipe

[Jeffy]

The front driveshaft does not turn if you don't have a locker ON or 4WD engaged.

[oldjeep]

The front driveshaft does not turn if you don't have a locker ON or 4WD engaged.

It certainly does if you have eliminated the vac disconnect like he has.

[neale_rs]

They probably messed up your axle seals during the insatallation or did not install the seal for the passenger side correctly.  When my gears were put in they messed up the passenger side and it all had to come apart again to install a new one.  Did both just to avoid similar work soon after.

Based on what I have read having the front shaft turning all the time usually does not cause any problems.

Number three does sound like you have a rear main seal leak, especially if the clutch is slipping.  Usually it is best to make sure it isn't just oil dripping from the back of the valve cover.