Rear/front diff

[NoMoGMPG]

Originally posted by rkcrawl:

The last thing to consider is that GM used a standard cut gear in the front which is well known to be weaker when used in a front axle application (vs a revese cut gear, think Hi-Pinion diff in the front). This is because the gears are running on the "coast" side of the ring gear teeth.

No, the front axles use a unique ring and pinion, they are not the same as any rear axle gear set. They do not use the coast side as the drive side. You may be thinking of Dana 44 gears from the 70's.

[f5fstop]

Originally posted by NoMoGMPG:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by HummBebe:
New question:

What does HUMMER consider a normal measurement for Backlash???

The tech who put in my new R&P said the old one was at .022 (thousandths) and that normal was from .006 - .010.

He said he thought along with the possible inconsistency with the hardening process, that the backlash was way off. He shimmed it to .010 thousandths.

Holy Shiite! .022"?!?!? That's horrible!

I set mine up at .006" but acceptable is up to .009", that may explain alot. I wonder if the case is distorted, no way GM would allow that kind of excessive clearance. </div></BLOCKQUOTE>

I guess my first question would be as damaged as the gearing was, exactly how did he determine what the factory set backlash was? That damage was pretty massive, and other items were probably damaged inside the diff as well, and the stresses could have set off any measurement.

GM's spec for the backlash are:
0.003-0.010 in (0.08-0.25 mm)
With a preferred backlash of: 0.005-0.007 in (0.13-0.18 mm)

[fourfourto]

Originally posted by HummBebe:

quote:
Originally posted by fourfourto:
Could build date be estimated by sticker on frame on drivers side between the 2 doors?

Mine says 06/20/06



Shhhhhh.....no honey.



Look at the date.....It hasn't even happened yet.

T & A Affilliate
Fo T & A Monitor

Duh I got so exited at you calling me honey I didnt realize I wrote 06

It was 6/20/05 Is that close to build date ?

Hope everything works out with your rig

[rkcrawl]

Originally posted by NoMoGMPG:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by rkcrawl:

The last thing to consider is that GM used a standard cut gear in the front which is well known to be weaker when used in a front axle application (vs a revese cut gear, think Hi-Pinion diff in the front). This is because the gears are running on the "coast" side of the ring gear teeth.

No, the front axles use a unique ring and pinion, they are not the same as any rear axle gear set. They do not use the coast side as the drive side. You may be thinking of Dana 44 gears from the 70's. </div></BLOCKQUOTE>

What's unique about it? All I've read so far is in the material density nothing about how the gears are cut.

Standard cut, vs reverse cut gears are still very current. Its a low pinion design, its running on the coast of side of the ring gear teeth when used in a front axle application.

The backlash measurement is interesting...that would allow of a whole lot of slop between the ring and pinion.

[PARAGON]

Originally posted by rkcrawl:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by NoMoGMPG:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by rkcrawl:

The last thing to consider is that GM used a standard cut gear in the front which is well known to be weaker when used in a front axle application (vs a revese cut gear, think Hi-Pinion diff in the front). This is because the gears are running on the "coast" side of the ring gear teeth.

No, the front axles use a unique ring and pinion, they are not the same as any rear axle gear set. They do not use the coast side as the drive side. You may be thinking of Dana 44 gears from the 70's. </div></BLOCKQUOTE>

What's unique about it? All I've read so far is in the material density nothing about how the gears are cut.

Standard cut, vs reverse cut gears are still very current. Its a low pinion design, its running on the coast of side of the ring gear teeth when used in a front axle application.

The backlash measurement is interesting...that would allow of a whole lot of slop between the ring and pinion. </div></BLOCKQUOTE>These Ring/pinions are not interchangable front to back. These are designed for front wheel drive, so, obviously it's not on the "coast" side.

They've been dedicated ring/pinion sets for the front for quite some time.

[rkcrawl]

Originally posted by PARAGON:

These Ring/pinions are not interchangable front to back. These are designed for front wheel drive, so, obviously it's not on the "coast" side.

They've been dedicated ring/pinion sets for the front for quite some time.

I never said they were interchangable. What I *SAID* was a standard cut R&P is weaker when the SAME R&P set is used in a rear axle application.

So yes, a Dana 44 would be a good example because they are used in front and rear application, as would a Dana 60, etc.

The point about being designed for front applictations only doesn't matter with respect to how the teeth are cut on the ring and pinion.

Unless someone points to how these gears are cut differently, its still a standard cut R&P gear used in a front axle application, which means that the power is being applied to the weaker side of the ring gear teeth.

Under normal circumstances this is a meaningless point, but under wheeling coniditions it is a consideration, and that is what we are talking about here, aren't we?

The ring gear failed while wheeling, presumably in 4Lo. I'm not saying its the cause...but it may be a contributing factor.

In my opinion, anyway, which is based on my experience breaking numerous low pinion R&Ps.

[PARAGON]

I don't quite understand then. If the fact that it is a front application and how that relates to the orientation of the concave and convex sides of the teeth doesn't matter, than this is moot.

Apparently semantics is getting in the way here and I have no idea what you are referring to when you say "standard cut."

The gears are cut so that the true drive/convex side is the working side and the coast/concave side is not. 'bout all I know to say.