I just recently installed a teralow in my np231 behind the auto in my XJ. Everything went back together as it came apart. The problem I am having is that it makes a decent amount of noise in 2hi and through out all the T case gears. It also makes noise when the Tcase is in Neutral. The sound is like a woosh woosh sound. I called tera and they said that this is normal and that it should break in. I was just wondering if anyone had any expierence with noise until the gears mesh and wear in. Tera said wheel the crap out of it and it should go away. It just doesnt seem right that this is a normal sound. I have never heard of anyone having noises in 2wd..4low I can understand. As this happen to anyone before.I should of went atlas route. thanks alot ...RobK

I've heard that they get noisier - but in low range not high.

Yeah, this seems part of the deal with the Tera gears. The planetary assembly is spinning in 2wd and neutral as the sun gear is on the input shaft. Stick the case in neutral, engage a 1:1 gear in the tranny (that's 4th in the manual), set the engine revs at 1000 and you should count about 4 "whooshes" every second.

The planets are compound and the teeth on the smaller segment that engages with the ring gear are straight cut. Straight cut gears are noisy. They should get quieter with use, but don't hold your breath - it could take months.

If you've got any metallic knocking noises you have cause to worry - the planets may not be timed correctly.

My unit makes a lot of noise, not just the whirring gear noise, but a noise like shaking a can full of dried beans. This noise bugs the c$%^p out of me. I reckon the planetary assembly is not quite circular and this generates backlash. That's my diagnosis anyway. If anyone's got any other ideas I'd like to hear 'em (it's not that the planets are out of time).

mines quiet, except for when in low....

Mine makes no noise while in 2wd or in neutral. When I first installed my Teralow it made noise in 4low. At first it was in all gears whenever I was at pretty much neutral throttle (not on the gas and not totally off the gas) but now I need to be in 3rd around 2k RPM to get it to make any noises. With mine it seems like the noises are going away with time but I did notice a big difference even after the first time I wheeled it.

thanks for all the replys. I guess I need to wheel it <IMG SRC="smilies/usa.gif" border="0">

I wheeled it. It still has not stop making noise. It does not make any noise in 4wd neutral anymore. I am really getting aggravated. I am wondering if I messed up the timing on the planetary when I switched input shafts. Tera says no because the planetary went in so easy. I am thinking about returning the tera and going atlas. Brandon at Tera is going to stand behind the case. so well see. I have over 50 hours into the pos np 231. This sucks.

my 4:1 is noisy as hell... allways was since installed... wheels GREATTTTT. U get use to the noise..

most do make the noise...install a set of boggers and you won't hear it any more! <IMG SRC="smilies/eyemouth.gif" border="0">

Mine's noisy too. As long as it's not clanking, just wheel it.

-J

I reckon you've nothing to worry about. My planetary was originally out of time and made little or no gear noise (whirring) in high or neutral. Once it was timed correctly it made gear noise (whirr, whirr, whirr etc). It's been like this a couple of months and its been wheeled a few times. Gears are gradually getting quieter in 2WD and neutral.

Correct me if I'm wrong but you get plenty of gear noise with the Atlas also. Either way, getting a set of boggers will certainly fix it up!

Thanks for all the reply guys. I wouldnt care if the case made noise in 4 high or low. Its 2wd thats annoying. If I drove by any of your houses. The first thing you would say is what is the horrible noise and whats wrong with your jeep. I cant even drive through town without every one looking its that bad. And that sound is over 34x 10.5 biasply swampers. BTW I changed the fluid and it was fine. A little black from the molly lube but no metal. Im not a bitch but It sucks to have a rig that sounds broke after I dished out $800 on a tera low.