Noise from Underdrive transfercase gear set (1 Viewer)

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matzell

matzell

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I have searched and posted in another thread but not really getting the answers I am looking for. For those of you who have installed the 10% under drive gear set:
What gears did you buy?
Did they make noise from the begining?
Did the noise get quieter as the gears broke in?
Do you hear it with A/T's?
How many miles where on the t-case when installed?
How many miles do you have on the new gears?

I know the debate of do you need them or not. Are they enough. etc. I want to hear from those who have had them in for a while now and get feedback. I have a few customers that are considering a set but I do not want to install them and then have the complaints about the noise being too loud.

Thanks in advance,
Rob
 
Not sure how many miles I have on them, I guess about 10 to 15k, had them for about 3-4 years now. Current 245k on the clock with stock 4.11 in the pumpkins. Running 35" Pro Comp Xtreme Mud Terrains. Bought the UD gear from Cruiser outfitters.

The wine is there immediately and has not diminished. It is not loud, more like a soft electronic humm. I did not notice it for a few days after the install. My wife nor son notice it. It is about equal, in volume, to adding my snorkel and not as loud, by a long shot, compared to removing the resonator when I installed the Labs bumper. My rig is not quiet. The MTs, snorkel, gear set all add to it being a bit loud in the cabin. I am currently installing Killmat, thicker carpet, noico foam and a isolation membrane to help quiet it down.

Would I do it again, yes, in a heartbeat. Is the UD a world changer - no. The UD, in concert with the low range gear set, is a huge improvement off road and noticeable on the street. The cost of the UD is really nothing if you are doing the low range gears which I highly recomend. If you can't pony up the $ for changing to 4.88s in the diffs (yes I know, these are closer to 4.56s) don't wait to do this swap. However, if you can spare the additional cabbage for regearing the diffs, I would do that over the UD if you are going to run 35s.

I am hoping to get ZUK to regear mine to 4.88s here this year that is, if I can ever get the rest of the stuff I have going on with the rig done first. (interior refurb, dual batteries, new LED ext lighting all the way around, new stereo and amp, switchpro, puma air compressor, hydro boost brakes, power steering cooler and QPM mount from Witsend etc.) I am going to leave the UD gears in for a while to see how I like them. May even bump to 37s. This is not my DD so I can play with it a bit.
 
forum.ih8mud.com

Under-drive plus Low-Range review

For those of you considering the 10% under-drive gears, the low range gears, or both inside transfer case, here are my thoughts as I recently installed both sets into my transfer case. To begin with, my 80 is very well maintained, it pretty quiet running down the road, and I know it...
forum.ih8mud.com forum.ih8mud.com

I would definitely do it again. In my case virtually unnoticeable noise. Continues to satisfy me after thousands of miles.
 
I install a set along with LR gear and part-time spool about 2 year ago. My does have a slight humming/whining come from the transfer case but compare to the 35 mud tires, it's not that bad. I try to adjust the output shaft bearing preload 4 different time but doesnt seem to help. Also i try different gear oil from 75-90, 75-110 and 75-140 but the noise still there.
After 2 year, i have no issue beside the noise. Would i do it over again, the answer is yes.
 
I have the Sumo gears, they were installed with 275k on the Reg about a year ago.
I don't really here them but I am running mud terrain tires.
For me it was a must as I am running 39s and it made a big difference.
I would do it again in a heart beat
On the other hand my low range gears sing a song!!
 
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This is what I am after! Thanks and keep the replies coming.
 
Is there any type of prepping the new and old gears to help them mate better? I haven't installed my UD and LR gears yet. When I do I was thinking to take use a stone to slightly hone the tooth faces. Any thoughts to if this a good or bad idea?
 
In both case you mating new gears to old gears, plus the gears are not a perfect fit and to that the low rang gears are now spinning faster. I thing that you just half to except this going in or don't do it.
I am in no means professional mechanic, but there is no way I would touch those Gears with a stone
 
jwbc84 said:
Is there any type of prepping the new and old gears to help them mate better? I haven't installed my UD and LR gears yet. When I do I was thinking to take use a stone to slightly hone the tooth faces. Any thoughts to if this a good or bad idea?
Click to expand...
You can send the gears to have them super finished. WPC uses fine ceramic to smooth the finish allowing better mating and less heat.

Not cheap though. Pricing is about $250 for the 9" ring and pinion set and $200 for the the 8".




WPC - Metal Surface Treatment / Micro Shot Peening

www.wpctreatment.com www.wpctreatment.com
 
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JMHO but were talking new to old gears and slightly mismatched gears. I don't think any amount of polishing is going to fix that.
Generally you don't Mix old gears with new gears, we do it because lower gearing is more important then the noise that it makes.
 
I fully accept that there might be some whine in the gears but I think a gentle touch up on the existing tooth face might actually help sest the two gear together as they wear. I could also be completely wrong. It is interesting that some people are getting more noise than others. I wonder if it is in the condition of the existing gears, something in the set up, tolerance variation in the new gears, break in, or who knows.
 
Just installed %10 underdrive from Sumo and Low range from trail gear in my ‘91.
The hi range gear is quiet, at least as quiet as it was before. The low range is whiny. Whatever.
 
For one the gears are turning three time as fast.
 
Noticing a slight whine in high (10% under drive) but not sure if it is any more than stock. I had planned to make a recording before and after but forgot. Very happy with the combo running 33" tires.
 
jwbc84 said:
Noticing a slight whine in high (10% under drive) but not sure if it is any more than stock. I had planned to make a recording before and after but forgot. Very happy with the combo running 33" tires.
Click to expand...
Nice. Planning on 33’s after the 31’s are used up. Might look a little out of proportion when I lift it 2” before I put the 33’s on
 
The only thing that I found that you need to know is to note the orientation of the shift collar.., everything else is kind of self explanatory
 
I've had mine about 16 months and 20K miles, there is a noise, if this was my DD/commuter I would probably be more religious about keeping it all silent, but as it is it doesn't bother me. My kids still fall asleep in the backseat on the highway and the radio is pleasantly audible over it without blasting.

The gear noise is louder than the noise of Falken Wildpeaks but lower than muds. I'd definitely do it again for the advantage moving 35s on the highway as well as the low-range offroad is fantastic.

If building the "perfect" 80 I'd probably do axle gears + just the low range gears, but the cost advantage of leaving the axles alone made sense to me to go with the underdrive.

I wrote up my experience doing it myself here.
 
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