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Transfer case noise.

deltabronco

Bronco Guru
Joined
Dec 27, 2005
Messages
1,100
Have a high pitch whine coming from by gearbox. It tends to quite not get louder depending on where the shifter is placed. I checked and fluids are good. Is there any way to remedy this or am I looking at a rebuild?
 

rydog1130

Bronco Guru
Joined
Jun 19, 2014
Messages
4,019
my bronco had kind of a whine to it too, similar to the noise you hear tanks make in the movies but since I topped off all the diffs and transfer case it's gone...maybe check your front and rear axel diff levels too.
 

SHX669

Bronco Guru
Joined
Jan 9, 2009
Messages
1,997
I assume you're talking about hi range 2 wheel drive.
How does it sound in Lo range?
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,833
Low range WILL make noise. No way around it, straight cut gears.
High range (especially in 2WD) should be quiet. If it makes noise, something is damaged. No additive will fix it.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,833
Are you sure it is the transfer case? Or from the transmission? Is this the stock 3-speed? Does the noise go away (or mostly) in 3rd gear? That is generally a bearing in the transmission. In 3rd the power is straight through and doesn't load the bearings which is why it will be quieter.
 
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deltabronco

deltabronco

Bronco Guru
Joined
Dec 27, 2005
Messages
1,100
Yes you can feel the whining vibrate through the shifter. If you move the shifter ( that shifts from 2h-4h-4L) left or right the noises tends to quieter down as if the internals are rubbing from the weight of the shifter. Yes it is a stock 3 spd c-4 transmission. Transfer case is a J type I believe.
 
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deltabronco

deltabronco

Bronco Guru
Joined
Dec 27, 2005
Messages
1,100
Are you sure it is the transfer case? Or from the transmission? Is this the stock 3-speed? Does the noise go away (or mostly) in 3rd gear? That is generally a bearing in the transmission. In 3rd the power is straight through and doesn't load the bearings which is why it will be quieter.

I believe the noise is loudest when it’s in 3rd gear but low speed.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,833
C4 automatic is completely different from a 3-speed manual. Planetary gearset vs. spur gearset.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,345
And you're sure it's shifted all the way out of 4wheel high Andy? Could it possibly be in 4wd?
Of course, easy to tell if you can just reach under and spin the front driveshaft, it's not in 4wd.

What about any body lift? Could the shifter be touching sheet metal under the boot?
Assuming it's a stock shifter that is? Not a twin-stick or something like that.

Checked that the rear pinion yoke nut isn't coming loose?

And lastly, the driveshaft will sometimes send strange noises up into the rest of the drivetrain and make it sound like one of the bearboxes. Every time I've run across a bad u-joint or yoke, it's been a different sound.
One possible test (though not definitive) would be to remove the rear shaft entirely and drive around in 4-wheel high range to see if the sound goes away or changes.

Good luck. A t-case rebuild is easy and relatively inexpensive as these things go. But it's still a hassle that would be nice to avoid.

Paul
 

PaveBronco

Sr. Member
Joined
Oct 30, 2012
Messages
912
Do you know what type of gear lube you're using, when I first brought my Bronco it whined, turned out the gear lube was the wrong type, way too thick. Rebuilt it many years later and learned about some gear oil has an additive that will eat your copper/brass??? bushings...
 
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deltabronco

deltabronco

Bronco Guru
Joined
Dec 27, 2005
Messages
1,100
And you're sure it's shifted all the way out of 4wheel high Andy? Could it possibly be in 4wd?
Of course, easy to tell if you can just reach under and spin the front driveshaft, it's not in 4wd.

What about any body lift? Could the shifter be touching sheet metal under the boot?
Assuming it's a stock shifter that is? Not a twin-stick or something like that.

Checked that the rear pinion yoke nut isn't coming loose?

And lastly, the driveshaft will sometimes send strange noises up into the rest of the drivetrain and make it sound like one of the bearboxes. Every time I've run across a bad u-joint or yoke, it's been a different sound.
One possible test (though not definitive) would be to remove the rear shaft entirely and drive around in 4-wheel high range to see if the sound goes away or changes.

Good luck. A t-case rebuild is easy and relatively inexpensive as these things go. But it's still a hassle that would be nice to avoid.

Paul

Thanks for info Paul.
 
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OP
deltabronco

deltabronco

Bronco Guru
Joined
Dec 27, 2005
Messages
1,100
Do you know what type of gear lube you're using, when I first brought my Bronco it whined, turned out the gear lube was the wrong type, way too thick. Rebuilt it many years later and learned about some gear oil has an additive that will eat your copper/brass??? bushings...

90 wt gear oil
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,345
I've read that fact time and time again for the last 25 years and still can't wrap my head around the real-world aspects.
Try to drain a quart of 50w motor oil and a quart of 90w gear lube and they sure don't act the same that way.
Same for using one of the good old Sta-Lube pumps. Man, pumping 90wt into a gearbox makes you think you just went a few rounds with the champ. Doing the same with either 50wt or even synthetic 75w/90 gear lube is not even in the same arena.

I guess there's enough spin inside the case to throw even cold 90w lube up into the output shaft section and keep the bearings lubed. But I always worried about that.
So I'm still going to use thinner gear lubes or the 50wt.

Paul
 
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