Anyone else break their transfer case?

[HummerNewbie]

Originally Posted by Sewie

And I purchased mine in early July '05 so it was probably a June build.

As long as they had this issue fixed by the time mine was built

[Sewie]

Originally Posted by HummerNewbie

As long as they had this issue fixed by the time mine was built

Good thing you waited so long, huh?

[HummerNewbie]

Originally Posted by Sewie

Good thing you waited so long, huh?

LOL As they say, good things come to those who wait

[f5fstop]

Originally Posted by NoMoGMPG

The lapping compound would not cause a fracturing of the gear, rather, it would lead to excessive backlash and a howling noise. The catastrophic failure is likely a manufacturing defect and American Axle is going to have alot of 'splainin to do, not to mention compensation to GM for warranty repairs.

Makes sense, but won't excessive backlash put more strain on the gear teeth? Not an expert in gears, unless they have electricity running through them.

[NoMoGMPG]

Originally Posted by f5fstop

Makes sense, but won't excessive backlash put more strain on the gear teeth? Not an expert in gears, unless they have electricity running through them.

Technically yes, but it would make noise, and alot of it, long before it would sharpen the teeth to the point of fracture. Normal backlash is .005-.009", someone posted here that their's were measured at .022" with the lapping compound issue. But that brings an interesting variable as excessive backlash could break teeth under a heavy shock load, maybe I need to re-think my position.

[HummBebe]

Originally Posted by NoMoGMPG

Technically yes, but it would make noise, and alot of it, long before it would sharpen the teeth to the point of fracture. Normal backlash is .005-.009", someone posted here that their's were measured at .022" with the lapping compound issue. But that brings an interesting variable as excessive backlash could break teeth under a heavy shock load, maybe I need to re-think my position.

That was me, the tech at the Moab 4x4 outpost is the person who said my backlash was .022. He even said that was a huge issue regarding the failure.

Someone then asked how could he know that, another expert said he could have simply turned the gear to measure.

Lapping compound was not an issue in my case.

[f5fstop]

Originally Posted by NoMoGMPG

Technically yes, but it would make noise, and alot of it, long before it would sharpen the teeth to the point of fracture. Normal backlash is .005-.009", someone posted here that their's were measured at .022" with the lapping compound issue. But that brings an interesting variable as excessive backlash could break teeth under a heavy shock load, maybe I need to re-think my position.

You probably know more than I do in regard to this area; but I'm learning fast.

As for Bebe's her failure was not due to excessive backlash or lapping compound. The only real lapping compound problems I have heard of are the early rear axles, and not all were affected. And, as you state, the noise gets people in at around 3-4K.

[Hummie2]

Just curious do all of the failed front diffs. have the off-road package with the 4:1 T-Case?

This is starting to look like a housing flex problem. What happens is that the differential gear teeth are tapered and they try to spread the diff. case apart when subjected to a high torque load. When the case spreads the teeth are no longer in proper mesh at that point (the teeth make a high flank contact similar to being setup with excessive backlash). A high flank contact severly loads the tooth on the ring gear and causes it to break away from the base of the ring gear. The measured .022" backlash would be indicative of a housing that was severly loaded enough to stretch the housing beyond it's elastic limit. The housing was sprung and never returned to it's original shape ( similar to overspreading a Dana housing too far when installing a gearset. A housing can be easily ruined if somebody gets carried away with the case spreader as they should never be spread more than a few thousands of an inch to facilitate getting the carrier and bearings back into the housing).

BTW- the tech that actually took time to do "failure analysis" and measure the backlash before removing the gearset is a pretty good tech. Most would never have bothered to take the time to check.

[Mike E]

For what it's worth, mine does not have the adventure package.

[rkcrawl]

Originally Posted by Hummie2

This is starting to look like a housing flex problem.

Interesting you bring this up, as case deflection is something I mentioned in my post in the other thread about the front diff grenading. I hope you are wrong otherwise we're going to see lots of these...

[HummBebe]

Originally Posted by Hummie2

Just curious do all of the failed front diffs. have the off-road package with the 4:1 T-Case?

This is starting to look like a housing flex problem. What happens is that the differential gear teeth are tapered and they try to spread the diff. case apart when subjected to a high torque load. When the case spreads the teeth are no longer in proper mesh at that point (the teeth make a high flank contact similar to being setup with excessive backlash). A high flank contact severly loads the tooth on the ring gear and causes it to break away from the base of the ring gear. The measured .022" backlash would be indicative of a housing that was severly loaded enough to stretch the housing beyond it's elastic limit. The housing was sprung and never returned to it's original shape ( similar to overspreading a Dana housing too far when installing a gearset. A housing can be easily ruined if somebody gets carried away with the case spreader as they should never be spread more than a few thousands of an inch to facilitate getting the carrier and bearings back into the housing).

BTW- the tech that actually took time to do "failure analysis" and measure the backlash before removing the gearset is a pretty good tech. Most would never have bothered to take the time to check.

I think you (and rckrawl) are definitely on to something.....!

Questions:

If the flex causes the pinion gear to shear off ring gear teeth, then this would occur under extreme "Flex" conditions? With IFS???

If the case has been flexed, ring gear damaged, is the housing still useable???

Should I have the differential housing inspected? Replaced?

Would a housing made from a different material (H3's are aluminum) be more stable?

Is there any manufacturers who produce a Cast iron or some other type of Steel housing?

Regarding the tech, he was exceptional. The entire Crew at Moab 4x4 Outpost is exceptional.

Thanks!!!!

Bebe

[NEOCON1]

thats what they did for me i have a nice shiney completely new front diff

[HummBebe]

Originally Posted by NEOCON1

thats what they did for me i have a nice shiney completely new front diff

I should have called Hummer like you did. Next time, slap me if I don't...K?

[NEOCON1]

i might pinch you on the bottom , but I would never slap you well , i guess i could slap you on the bottom

[NEOCON1]

Originally Posted by Alec W

I knew this had nothing to do with driver error. I hope GM reads the site and addresses the problem.

i should hope so Mr. Banzai driver

[HummBebe]

Originally Posted by NEOCON1

i should hope so Mr. Banzai driver

No....It's BAM BAM

[HummBebe]

Seriously though,

If this is the issue, I can see not having a recall, but for as much wheeling as I do, I want the fix....before it breaks again.

5 extra days in Moab, well it was fun, but I do not want to do it again.