Changing rear ratios

Drivetrain discussion including Transmission, Differential, Driveshaft, and related items.
User avatar
Crazy Paul
Posts: 149
Joined: Fri Apr 26, 2013 1:51 pm
Location: PERTH, Australia
Contact:

Re: Changing rear ratios

Post by Crazy Paul »

Image

Image
Navy Lifer
Administration Staff
Posts: 1724
Joined: Tue Mar 19, 2013 6:30 pm
Location: Canton GA

Re: Changing rear ratios

Post by Navy Lifer »

The GM PN for the service 2.92 ring & pinion (official GM term is GEAR SET - Group 5.529) is 92191335 (6.0 vehicles only) - VERY pricey, not sure why unless it happens to be the entire carrier/differential, but that is not normal GM procedure.

The 3.27 & 3.45 gear sets are much less pricey. From all I can tell, the alternate ratios will fit the PPV differential.

C.P., my local parts guy says it doesn't make sense for the R&P to cost nearly as much as the complete 2.92 differential - which is shown in Parts Group 5.510, for 2012 ONLY, where the PN 92157714 you listed displays for PPV, too, although not 2011 & 2013, even we KNOW they're the same for all 3 years (with V8)--it IS listed for G8 GT (2008-2009), also.

Doing a reverse search (using the PN to see what it fits), everything falls into place, as long as the search filters are set correctly.

GMPP also has a 3.91 gear kit from 1LE - PN 22813040 - that is a LOT of gear for a 6L80 (almost 16:1 starting ratio in 1st gear--a "granny" low)!

I'm not claiming this information to be the "last word"...the information in the US parts books for Holden-built vehicles remains a bit mysterious in some areas, since the "old school" parts guys are not used to some of the differences dictated, in this case (I suspect) by the IRS axles, etc.

From my earlier post on Auburn & Eaton replacement diffs for Gen5 Camaro, the question then becomes whether the G8 & PPV can use these diffs, or if it comes down to having to install a Camaro 218mm (SS) differential assembly, as Eric has done, to be able to utilize these US-sourced LSD's. If they will fit the G8 & PPV housings, it makes you wonder whether the manufacturers are so blind to the fact that Camaro & other Zetas are really similar underneath, since they're missing a market if these LSD's will fit.
User avatar
storm9c1
Posts: 418
Joined: Wed Mar 27, 2013 6:47 pm
Location: Pittsburgh, PA

Re: Changing rear ratios

Post by storm9c1 »

As usual, CP has great information. Thanks CP!

A few posts back, we were discussing Eaton versus Auburn. And it sounded like it turned into "opinions" versus "facts" type of discussion based on "old" information and rumors from 15 years ago. Unfortunately, my tone must have tripped the "opinion" flag. That's fine. I was speaking from experience. And I guess I failed to convey "why". Granted I have no experience with a modern Auburn unit from any current model cars, but based on the Auburn site, the designs haven't changed. Even in 15 years.

Opinions aside, for those who don't know the difference, study these and form your own "opinions".

Here is a common Eaton design. Notice the clutches on each side. These are like transmission clutch plates and can be replaced:
Image

Here is the Auburn design. There are no clutch plates. Instead, the spider gear is a cone shape that relies on friction to the case. Unfortunately as the gear wears, it destroys the case with it:
Image

I know which design I choose. And there is a reason GM likes this unit (it's cheaper folks!). And I hope seeing the designs side by side helps other choose. If I planned on putting an aftermarket gear set in my PPV, I would certainly switch to a Eaton design if there is one that is compatible. Does anyone know if Eaton makes a carrier for any of the diffs we've been discussing?
Tom (AKA: Storm)
2011 Caprice 9C3: L77, 8K miles, first-owner, purchased July 2011.
1995 Caprice 9C1: LT1, 178K miles, summer car.
1995 Impala SS: LT1, 21K miles.
1995 Caprice Wagon: LT1, 62K miles.
1995 Caprice Wagon: LT1, 128K miles. Rust In Pieces
1994 Caprice 9C1: LT1, beater winter car.
1969 Chevy C30: 383ci stroker, 4L80E, rollback car hauler.
1972 Chrysler Newport: 400ci big block, survivor 27K miles, 2-door hardtop.
1969 Dodge Charger: 383ci big block.
User avatar
Crazy Paul
Posts: 149
Joined: Fri Apr 26, 2013 1:51 pm
Location: PERTH, Australia
Contact:

Re: Changing rear ratios

Post by Crazy Paul »

storm9c1 wrote:Does anyone know if Eaton makes a carrier for any of the diffs we've been discussing?
Search Google "VE Harrop Truetrac" & "VE KAAZ"

http://www.transgearsdiffs.com.au/diff-specials.html" onclick="window.open(this.href);return false;
http://www.gumtree.com.au/s-ad/seven-hi ... 1023881976" onclick="window.open(this.href);return false;
http://www.harrop.com.au/drive_detail.p ... TRC9823-00" onclick="window.open(this.href);return false;
http://www.tuspeed.com/harrop-truetrac- ... -1435.html" onclick="window.open(this.href);return false;
http://www.otomoto.com.au/p/4523268/os- ... lease.html" onclick="window.open(this.href);return false;
http://www.ebay.com.au/itm/Genuine-Hold ... 0524789364" onclick="window.open(this.href);return false;
http://www.ebay.com.au/itm/Motive-VE-Di ... 1015324254" onclick="window.open(this.href);return false;

For those who are comparing the Harrop/Eaton and the Eaton True Trac Please understand that the 2 units are “not” the same
Harrop in Australia had been the pioneer in development of this unit and Eaton partnered with them and had supplied the internal components for this unit
Yes both the Eaton USA and the Harrop/Eaton units share similar internal components but they are 2 different differentials
The Harrop units are made of billet and are hand fitted, the Eaton units are the tried and true forged housing manufactured on production tooling
Harrop/Eaton units are hand built of the finest billet materials available hence the price differential between the 2 units
Also to be noted is that the Eaton unit has an advertised 500HP rating and the Harrop/Eaton Billet unit is at 500KW rating
Do the math and please make your choices accordingly

Regards
Eaton Performance Products
Navy Lifer
Administration Staff
Posts: 1724
Joined: Tue Mar 19, 2013 6:30 pm
Location: Canton GA

Re: Changing rear ratios

Post by Navy Lifer »

storm9c1 wrote:A few posts back, we were discussing Eaton versus Auburn. And it sounded like it turned into "opinions" versus "facts" type of discussion based on "old" information and rumors from 15 years ago. Unfortunately, my tone must have tripped the "opinion" flag. That's fine. I was speaking from experience.

Opinions aside, for those who don't know the difference, study these and form your own "opinions".

Does anyone know if Eaton makes a carrier for any of the diffs we've been discussing?
Tom, I, too, have plenty of experience, not just opinion--the lovely Eaton GovLoc is another fine example of GM's "going for the cheapest", right along with the Auburn you've expressed such distaste for.

I guess I'm curious if you have ever--or do you know anyone who has--actually rebuilt an Eaton Posi? I'm not arguing your point, as far as what happens as an Auburn LSD wears, but in the end, regardless of which brand is in use, they do wear out--that's their nature.

Maybe you missed the links (below) from a previous post--yes, Eaton has a Detroit TrueTrac (helical gear) LSD, though not yet confirmed to fit the VE/VF/WM/WN rear axle, since it's advertised as being for Gen5 Camaro. I've submitted an inquiry to Eaton to find out if the Camaro LSD will fit PPV, G8, etc., and will report on their response.
Navy Lifer wrote:http://www.auburngear.com/aftermarket/n ... fnews.aspx

http://www.lsxtv.com/news/new-products/ ... -sema-show" onclick="window.open(this.href);return false;

http://www.lsxtv.com/tech-stories/drive ... camaro-ss/" onclick="window.open(this.href);return false;
Not to sway you - the new Auburn Gen5 Camaro unit has 4 spider gears, and Auburn also offers the D-Rex program for replacement of a failed aftermarket unit within a specific amount of time after purchase (3 or 4 years?), regardless of how it's used (ie. racing is OK). I do look at that as an acknowledgement that their units DO fail in a mode that requires a new unit to make it whole again, and I understand why that is not a popular thing in many instances, including your own.
User avatar
storm9c1
Posts: 418
Joined: Wed Mar 27, 2013 6:47 pm
Location: Pittsburgh, PA

Re: Changing rear ratios

Post by storm9c1 »

Tom, I, too, have plenty of experience, not just opinion--the lovely Eaton GovLoc is another fine example of GM's "going for the cheapest", right along with the Auburn you've expressed such distaste for.

I guess I'm curious if you have ever--or do you know anyone who has--actually rebuilt an Eaton Posi? I'm not arguing your point, as far as what happens as an Auburn LSD wears, but in the end, regardless of which brand is in use, they do wear out--that's their nature.
I'm not too impressed with the GovLoc either.

And yes, way back when I was racing B-Bodies somewhat regularly, I knew a mechanic (the same one who did my 3.42 gears and carrier) who taught me the problems with the Auburn units. He was the first to show me the failure mode -- he had one disassembled on the bench and pointed out why they fail. He also pulled out a crate full of broken Auburn units. He was a racer too and probably broke a few of those units himself. He is the one who first recommended the Eaton units and he would also rebuild them for $200 a pop with new clutches. This included all of the labor. (that was 15 years ago pricing when the shop rate was $40/hour, I think his rate is now $80/hour). Back then it was worth more for me to pay him than to do it myself. Now I would gladly do it myself since I have a fully equipped shop now...and his shop is much further away since I moved.

Don't get me wrong, the Eaton units aren't perfect. I have noticed play in them -- not out of spec according to a dial indicator -- but enough to cause an annoying clunk. I just like them better than the Auburn units.

Yes, things are different now, I might be a little behind the times, but I still have the images of those bad Auburn units embedded in my memory and I've burned up a few myself. So I'm a little weary of them. As I said before, folks can form their own opinions I guess.
Tom (AKA: Storm)
2011 Caprice 9C3: L77, 8K miles, first-owner, purchased July 2011.
1995 Caprice 9C1: LT1, 178K miles, summer car.
1995 Impala SS: LT1, 21K miles.
1995 Caprice Wagon: LT1, 62K miles.
1995 Caprice Wagon: LT1, 128K miles. Rust In Pieces
1994 Caprice 9C1: LT1, beater winter car.
1969 Chevy C30: 383ci stroker, 4L80E, rollback car hauler.
1972 Chrysler Newport: 400ci big block, survivor 27K miles, 2-door hardtop.
1969 Dodge Charger: 383ci big block.
leadfart
Posts: 465
Joined: Wed Mar 20, 2013 12:00 am
Location: Treasure Island, Lake McQueeney, TX

Re: Changing rear ratios

Post by leadfart »

I would never run an Auburn unit, and I have "extensive" experience, both empirical, and scientific, with both Auburn and Eaton. :mrgreen: Of course, I realize several thousand passes down the strip don't necessarily make me an expert, maybe just stupid! :o

Carry on. 8-)
Bob Dannelley
2011 Alto Gray 9C3 Caprice PPV-Maggie-11.64@119.68-Sold!
1995 DCM Impala SS-409-Stroker!-11.83@115
2014 Silver Ice LTZ Silverado Crewcab 4X4
2007 Black Z51 M6-Corvette Coupe
User avatar
elc32955
System Manager
Posts: 2718
Joined: Thu Nov 29, 2012 10:32 am
Location: East Central Florida
Contact:

Re: Changing rear ratios

Post by elc32955 »

Just a quick update, I went to the local dealership today to have the rear drained and filled with the stock GM fluid and the LSD additive. I can't lift the car in my driveway and my days of shinnying under a jacked car are pretty much over unless it's an emergency. The dealer wrote it up and took it back into the service bay, and then the service staff discovered they had none of the proper lubricant on the shelf.

So, next week for sure I'll be able to tell you if the noise quiets down with the proper spec. lubricant, my bet is the noise goes away. I had plenty of comments from the service writer about "you're the first ever in the dealership for a rear diff service with a Caprice", and the corresponding 6-7 staff & mechs all over the car.

Next thrilling chapter soon :)

Eric
System Manager and your tour guide for the day. 2015 Caprice w/LFX, former NC DPS staff car. Partial hybrid G8/SS/Camaro SS interior mods, SS MyLink radio upgrade, 2016 Camaro V6 rims, GMPP Malibu chrome exhaust tips, otherwise bone stock for now.
Navy Lifer
Administration Staff
Posts: 1724
Joined: Tue Mar 19, 2013 6:30 pm
Location: Canton GA

Re: Changing rear ratios

Post by Navy Lifer »

Navy Lifer wrote:Eaton has a Detroit TrueTrac (helical gear) LSD, though not yet confirmed to fit the VE/VF/WM/WN rear axle, since it's advertised as being for Gen5 Camaro. I've submitted an inquiry to Eaton to find out if the Camaro LSD will fit PPV, G8, etc., and will report on their response.
No response from Eaton, so far, but some research at the dealer indicates that the PPV and Camaro (V8's) do NOT use the same carrier bearings. Does not rule out the possibility of the Eaton (or Auburn) Gen5 diff from working, just depends on whether there may be conversion bearings needed, if it may be "that simple".....again, will report when (or IF) Eaton responds.
User avatar
Crazy Paul
Posts: 149
Joined: Fri Apr 26, 2013 1:51 pm
Location: PERTH, Australia
Contact:

Re: Changing rear ratios

Post by Crazy Paul »

elc32955 wrote:Just a quick update, I went to the local dealership today to have the rear drained and filled with the stock GM fluid and the LSD additive. The dealer wrote it up and took it back into the service bay, and then the service staff discovered they had none of the proper lubricant on the shelf.
G8's with the same diff use Part Number 92184900 which is a one litre bottle. Completely empty Diff takes 1.25 litres.
Image
http://paceperformance.com/i-5132570-92 ... oz-1l.html" onclick="window.open(this.href);return false;
Post Reply