Pinion Bearing

Hunter

Well-known member
Apr 20, 2004
120
1
Charleston, SC
www.geocities.com
Hey Dweb,

Need some help with what i think is a bad pinion bearing.

I have a "rotary sounding rumble" coming from the rear. Happens at 5-7 mph with foot OFF gas. Once going faster it goes away. Wheel bearings are tight. New arb just professionally installed with new carrier bearings. (The noise was happening before the arb install and is unchanged after the install). Yanking on the pinion flange shows no give or wobble. Pinion seal is leaking. If i disconnect the rear driveshaft, and drive around with just front wheel drive, the noise goes away.

What else could it be if its not the pinion bearing? Should there be play in the pinion flange if its the bearing? Pinion nut is tight.

If anyone thinks its the bearing, can i replace it from the front end (pinion end) of the 3rd member?

Any help much appreciated!!

Hunter :confused:
 

marc olivares

Well-known member
Apr 20, 2004
3,535
0
without hearing it, it sounds like the pinion preload is to loose.
but to much backlash or a bad pinion bearing will also cause a similiar sound

when the arb was installed, were the pinion bearings also replaces?
or did they simply put on a new carrier and carrier bearings?

in any case the diff will have to be set up again to replace the pinion bearings.
can not replace the bearing "from the front of the third member"
make sure pinion preload is around 20-25 inch pounds
backlash is .004-.008 (3.54 gears), .008-.012 (for GBR 4.1 gears)
and the runnout is 0.

as for the pinion seal leak, make sure your breather tube is clear, a plugged tube is typically the cause of the seals leaking.
 

Hunter

Well-known member
Apr 20, 2004
120
1
Charleston, SC
www.geocities.com
Pininon Bearing

Thanks Marc,

That's depressing about having to resetup the diff, but no they didn't replace the pinion bearing while it was out. Guess i'll pull the 3rd member and take it to someone to fix properly. Could it be anything easier? U joints are tight--

How much slop should there be in the rear diff and axles when you turn the rear drive shaft by hand? i had quite a bit (maybe a quarter turn of the driveshaft)

One other confounding factor. When i was pulling the 3rd member to send off to have the arb installed, i found this piece in the rear diff--hmmmm.... know what it is?? one side has a metal ring exposed, the other side is rubber casing for the ring. maybe this is what's made everything so loose.

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Hunter

Well-known member
Apr 20, 2004
120
1
Charleston, SC
www.geocities.com
PB ctd.

does the image i posted look like the pinion spacer by any chance?? if so, how did it get to the bottom of the diff?? or perhaps its from one of the axles? its got a metal side and a rubber side and the i.d. is about 1.5 inches.

thanks!
 

marc olivares

Well-known member
Apr 20, 2004
3,535
0
that part looks like an axle housing seal, there are two, one on each side of the axle housing tubes. they are there to keep gear lube separate from the wheel bearings.
i'm guessing that it spun loose and floated to the carrier side of the axle. when you pulled the axle shaft it dropped the seal into the diff housing.
if that is the case, there wouldn't be any damage to the diff from this part. lots of guys pul these seals and run the wheel bearings on gear oil like most domestic oil bath full floating axles. these seals were land rovers fix or leaking axle flanges, resulting in dirty oily wheels.

the free play you feel in your diff is way to much, perhaps the backlash was set incorrectly. i would start by checking this first.

if you suspect that maybe the rear u-joints are going bad, remove the shaft and take to a drive line shop and have the balance checked. this typically costs less than $20 and will tell you the condition of the rear shaft.

but based on what you have described, it sounds like a diff issue to me.....

unless you have left out more info?
 
S

Sergei

Guest
Another bit could be bolts tightened unevenly (or just not tight enough) between shaft and flange (either one). So it would throw shaft offbalance a bit.

And if you upgraded rear flange (you sppsedly should, if upgrading to arb), then there is that stupid spacer thingy, that goes onto pinion before flange. If you aint got it there - there will be all sorts of moaning and groaning :) (and how i know? correct - i screwed mine first time :)) And another thing , if you upgraded shaft to SG/TW/GBR one - which end you used adapter and cardan joint at?
 

Hunter

Well-known member
Apr 20, 2004
120
1
Charleston, SC
www.geocities.com
PB ctd.

Well, a little new news,

i do still hear the rumble, though intermittently much less often with the driveshaft off. Been driving around with the rear shaft off with the center diff locked. My plan i guess is to take out the friggin 3rd again and the rover tech at LR Columbia said he'd look at it for me. I just wish he didn't have to tear into my freshly installed arb. Oh well huh.

Another issue, now that i've been driving around with just the front shaft, is the enormous abount of play in the front shaft or diff. Do you all have this when just running the front drive. Huge "clack" (bigger than normal) when putten er in reverse. Any thoughts.

Thanks for the help!
 

Tom in MD

Well-known member
Apr 20, 2004
149
0
Sarasota, USA
Pinion seal

That pic you posted looks like the pinion seal. They wouldn't have had to replace it for your install, but should have. Are you running rotoflex or U-joint ? If you've done the U-joint conversion, there should have been a spacer behind the seal. Without it, things just kinda flop around as you cannot tighten the pinion nut down completely. I forgot it the first time (too, Sergei) I put mine back together and it only took about 20ft to realize I F'd up. The item in the picture is not the spacer.

My front-drive-only experiance was identical to yours. Lot's of play complete with huge clack. After getting the rear drive back in working order, it all quieted back down.
 

marc olivares

Well-known member
Apr 20, 2004
3,535
0
tom and sergie

re-read his post, he says that he found the seal in the third after he had pulled it.
there is no possible way that a pinion seal could be inside of the third member.
just doesn't go together that way.

inner axle seals

hunter, with out the rear shaft, the backlash noise will resonate more.
it sound normal to me (as you describe it).
 

Hunter

Well-known member
Apr 20, 2004
120
1
Charleston, SC
www.geocities.com
been driving around with the front drive shaft only and i think ive found it!

looked under the truck today for s*its and giggles and found that the parking brake drum screw (not the nut) was exceedingly loose. tightned it up and no rumble!

i guess it makes sense cause there really is no play in the pinion flange and the arb was installed by guys who do it all day.

i'll reattach the rear drive today and give you an update.

the picture IS and axle seal, the pinion spacers can't get back to the diff.
no big deal there!

THANKS FOR YOUR HELP!!!
 
S

Sergei

Guest
Marc 0 i havent said anything about seal :)

Hunter - glad you got it sorted out. I'd suggest to take nut off, put some red threadlocker on it and then tighten it. Thats way it wont become loose all the sudden after trip or two..