8.5 posi clutches New Supplier
February 8th, 2012, 08:12 AM
#1
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8.5 posi clutches New Supplier
Here is a new supplier of the o-axle and corporate 10 bolt 8.5 posi clutches , they are made in the USA and are made from the same material that the oem 's were made of . Here is his e-mail address , BPonti442@aol.com . He has pictures and pricing for those who are interested . They look good and should work as well as the oem's if not better . BOB .
February 9th, 2012, 05:11 AM
#3
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Location: Erie,PA
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I have known Bruce Ponti for many years,and he is one of the best diff guys out there.He's also the one that tipped me about GM discontinuing the 8.5" clutches.We have traded a variety of tips & tricks throughout the years.
February 9th, 2012, 07:11 AM
#4
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Jim , he listed the prices as , $199 for 1 to 4 sets , $159 for 5 to 19 sets , $129 for 20 and over sets plus shipping . They come with 12 selective shims , 2 each of .010 to .035 in .005 increments . I have pictures but have not figured out on how to post them yet . BOB .
February 9th, 2012, 04:13 PM
#5
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Subject 8.5 Clutch Kit Pics Sender BPonti442@aol.com
Recipient
Date Tue 8:07pm
Bob -
Below and attached are pics of the 8.5 clutch kit. As you can see, there are 8 tabbed, 6 splined along with 12 selective shims, 2 each ranging from .010 to .035 in .005 increments. The prices at the moment are fixed at $199 retail (1 to 4 kits), $159 jobber (minimum order of 5 up to 19 kits), and then $129 wholesale (minimum order 20). There will be a small shipping fee, but NO handling charge. This is a heck of deal considering the GM kits are no longer available and when they were, you didn't get shims. Plus, we have a lot of money tied up in research along with the dies needed to produce these. In all likelihood, there will be no profit made from these on our part until many kits are sold, and even then, it will be nominal. We did this to help ourselves out along with local enthusiasts and hobbyists.
These kits are 100% US made, from the steel to the tooling. We had the metal tested for Rockwell hardness and it specs out the same as the factory. We went with the cross hatch surface pattern (like a Chevy 12 bolt clutch) instead of the fish eye pattern for two reasons; first, the die to stamp the pattern was less costly which keeps the costs of the kits down, and secondly, this pattern offers superior lubrication which will enhance the life of the clutch. We are taking preorders right now. Once payment is received, we should be able to ship the first orders within 3 weeks. If you have any questions, please feel free to give me a call.
Recipient Date Tue 8:07pm
Bob -
Below and attached are pics of the 8.5 clutch kit. As you can see, there are 8 tabbed, 6 splined along with 12 selective shims, 2 each ranging from .010 to .035 in .005 increments. The prices at the moment are fixed at $199 retail (1 to 4 kits), $159 jobber (minimum order of 5 up to 19 kits), and then $129 wholesale (minimum order 20). There will be a small shipping fee, but NO handling charge. This is a heck of deal considering the GM kits are no longer available and when they were, you didn't get shims. Plus, we have a lot of money tied up in research along with the dies needed to produce these. In all likelihood, there will be no profit made from these on our part until many kits are sold, and even then, it will be nominal. We did this to help ourselves out along with local enthusiasts and hobbyists.
These kits are 100% US made, from the steel to the tooling. We had the metal tested for Rockwell hardness and it specs out the same as the factory. We went with the cross hatch surface pattern (like a Chevy 12 bolt clutch) instead of the fish eye pattern for two reasons; first, the die to stamp the pattern was less costly which keeps the costs of the kits down, and secondly, this pattern offers superior lubrication which will enhance the life of the clutch. We are taking preorders right now. Once payment is received, we should be able to ship the first orders within 3 weeks. If you have any questions, please feel free to give me a call.
February 9th, 2012, 06:53 PM
#7
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Join Date: Jul 2006
Location: Richfield, Oh
Posts: 1,737
clutches
I was trying to have them made too... But kind of gave up - the price could not be kept in a better range.
I guess if your going for resto it is not bad...But if you double the money you get a complete posi unit that is 30-40% stronger design and will always have parts around to rebuild.
It is nice for guys to have that option. Still prefer customers to upgrade as the power of the cars keep increasing so our posi parts and transmission parts must also follow. Been testing the true trac out and that seems to work well in all ranges and types of driving.
Just some thoughts.
Remember these clutches will fit your Olds 12 bolt unit too. Jim
JD
I guess if your going for resto it is not bad...But if you double the money you get a complete posi unit that is 30-40% stronger design and will always have parts around to rebuild.
It is nice for guys to have that option. Still prefer customers to upgrade as the power of the cars keep increasing so our posi parts and transmission parts must also follow. Been testing the true trac out and that seems to work well in all ranges and types of driving.
Just some thoughts.
Remember these clutches will fit your Olds 12 bolt unit too. Jim
JD
February 20th, 2013, 06:39 PM
#9
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Join Date: May 2012
Posts: 63
8.5 posi unit clutch kit
I don’t know how many times I have seen someone reply about replacing their corporate 8.5 posi unit with an Eaton unit. Although a good option, the better option is to rebuild your factory unit. Many of those individuals that recommend replacing that unit are dealers trying to sell you a very expensive Eaton posi. This reply is not meant as a personal attack to those folks, but is meant to be informative and set the record straight for those that have only heard one side of the story. I have over 25 years experience in the industry and have built hundreds of rear ends of all types and as well as hundred (if not more) posi units of all types. I have been published in GM High Tech Performance, Fast Fords and Muscle Mustangs and soon to be Super Chevy. With that being said, let’s get down to it. The corporate 8.5 posi unit manufactured from ’71-‘early 88 is one of the FINEST and strongest OEM units made to this date. It has the advantage of using carbon steel clutch discs that have a relatively high Rockwell hardness and a one piece 300 lb preload spring commonly referred to as an “S” spring. Because of the one piece design of the spring, there is no shifting of the spring when the clutch discs have excessive wear. Due to this design, this unit remains relatively quiet even when the clutches are almost completely worn out. The strength of the unit comes from the fact that the internal gears are forged metal. If the differential was properly serviced in its lifetime, the unit will show little internal gear wear. As all mechanical parts if it is improperly maintained or there is mechanical defect in that particular casting/forging, there will be issues. These are uncommon though. I have personally witnessed these units run in the mid 9s behind some high horsepower and high torque engines with NO ISSUES what-so-ever. Now, the NEWER Eaton units are good units, but they have limitations as well. First off, they use powdered metal internals that tend to fail under high performance applications. It was my intention to take some photos today of blown internals on an Eaton unit and post it here but I simply did not get around to it. I will do so and post them here soon. Additionally, these units use Carbon Fiber clutches. These are very quiet and maintain very consistent handling characteristic for the vehicle. This information came straight from Eaton Tech reps at the last PRI Show when I asked them why they didn’t use the steel clutches still available for purchase. The downside to the carbon fiber clutches is they cannot tolerate abuse over a long period of time (also confirmed by the Eaton rep). Once the clutches wear, then the 4 – 400 lb preload springs and 2 flat plates begin to shift. This is when people complain their diff is “popping and clicking”. At this point, the best thing to do is throw the carbon fiber clutches out and rebuild the unit with the steel clutches. Having extensive experience with both, I can tell you I would much rather spend the money to rebuild the factory unit than spend twice the money (If not more) on an Eaton unit. There are other units out there too, such as Auburn cone types, Eaton Detroit Tru-Tracs which use helical gears, Yukon Gear which is an Eaton type unit with FORGED internals, and of course the Eaton Gov-Lok which no one should ever consider using in a high performance application. They are fine in a low power stock application where the vehicle is not being abused. ALL the options above have their limitations and in their NEW form are more expensive than rebuilding your oem 8.5 unit. I recently rebuilt an 8.5 for a gentleman out of Kennesaw, GA. His car went 10.68 with a 1.58 60 foot and worked flawlessly and still it. I hear this all the time. Anyway, I hope this clears up a little confusion. Don’t go out and waste your money just because someone says you should, especially if they are a dealer in that particular unit. Do your research and for those of you who decide you want to go ahead and buy a new unit anyway, please feel free to get a hold of me. I will buy your old unit and you can use the proceeds to cover the cost of a new one. I can’t have enough of these on my shelf.
V/r
Bruce
V/r
Bruce
Last edited by bponti442; February 20th, 2013 at 07:17 PM. Reason: Misspelling
February 26th, 2013, 06:08 AM
#13
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Join Date: Jul 2006
Location: Richfield, Oh
Posts: 1,737
I don’t know how many times I have seen someone reply about replacing their corporate 8.5 posi unit with an Eaton unit. Although a good option, the better option is to rebuild your factory unit. Many of those individuals that recommend replacing that unit are dealers trying to sell you a very expensive Eaton posi. This reply is not meant as a personal attack to those folks, but is meant to be informative and set the record straight for those that have only heard one side of the story. I have over 25 years experience in the industry and have built hundreds of rear ends of all types and as well as hundred (if not more) posi units of all types. I have been published in GM High Tech Performance, Fast Fords and Muscle Mustangs and soon to be Super Chevy. With that being said, let’s get down to it. The corporate 8.5 posi unit manufactured from ’71-‘early 88 is one of the FINEST and strongest OEM units made to this date. It has the advantage of using carbon steel clutch discs that have a relatively high Rockwell hardness and a one piece 300 lb preload spring commonly referred to as an “S” spring. Because of the one piece design of the spring, there is no shifting of the spring when the clutch discs have excessive wear. Due to this design, this unit remains relatively quiet even when the clutches are almost completely worn out. The strength of the unit comes from the fact that the internal gears are forged metal. If the differential was properly serviced in its lifetime, the unit will show little internal gear wear. As all mechanical parts if it is improperly maintained or there is mechanical defect in that particular casting/forging, there will be issues. These are uncommon though. I have personally witnessed these units run in the mid 9s behind some high horsepower and high torque engines with NO ISSUES what-so-ever. Now, the NEWER Eaton units are good units, but they have limitations as well. First off, they use powdered metal internals that tend to fail under high performance applications. It was my intention to take some photos today of blown internals on an Eaton unit and post it here but I simply did not get around to it. I will do so and post them here soon. Additionally, these units use Carbon Fiber clutches. These are very quiet and maintain very consistent handling characteristic for the vehicle. This information came straight from Eaton Tech reps at the last PRI Show when I asked them why they didn’t use the steel clutches still available for purchase. The downside to the carbon fiber clutches is they cannot tolerate abuse over a long period of time (also confirmed by the Eaton rep). Once the clutches wear, then the 4 – 400 lb preload springs and 2 flat plates begin to shift. This is when people complain their diff is “popping and clicking”. At this point, the best thing to do is throw the carbon fiber clutches out and rebuild the unit with the steel clutches. Having extensive experience with both, I can tell you I would much rather spend the money to rebuild the factory unit than spend twice the money (If not more) on an Eaton unit. There are other units out there too, such as Auburn cone types, Eaton Detroit Tru-Tracs which use helical gears, Yukon Gear which is an Eaton type unit with FORGED internals, and of course the Eaton Gov-Lok which no one should ever consider using in a high performance application. They are fine in a low power stock application where the vehicle is not being abused. ALL the options above have their limitations and in their NEW form are more expensive than rebuilding your oem 8.5 unit. I recently rebuilt an 8.5 for a gentleman out of Kennesaw, GA. His car went 10.68 with a 1.58 60 foot and worked flawlessly and still it. I hear this all the time. Anyway, I hope this clears up a little confusion. Don’t go out and waste your money just because someone says you should, especially if they are a dealer in that particular unit. Do your research and for those of you who decide you want to go ahead and buy a new unit anyway, please feel free to get a hold of me. I will buy your old unit and you can use the proceeds to cover the cost of a new one. I can’t have enough of these on my shelf.
V/r
Bruce
V/r
Bruce
Just some rebuttal on these facts.
THIS IN NO WAY IS TELLING YOU TO BUY OR NOT BUY FROM BOB OR SAY BRUCE IS ALL WRONG OR COMPLETELY RIGHT...JUST MORE FACTS AND EXPERIENCES TO BASE DECISIONS ON.
We are not here to knock anyone's stuff just supply facts and best we can.
Reasons Eaton unit is better or NOTbetter than track lock GM unit
The GM track lock 410409 410408 725 726 case design is the first and BIGGEST failure.
2 big open windows on this unit is the worst thing... This causes huge flex creating major backlash between the spider gear system when heavy launches are occurred. This will make the sidergear ride up on the tips cause thenm to tip each other and fail. AGAIN this is under hard track acceleration. Most all posi units any make will be absolutely fine on the street with out slick or excessive grip
All GM Factory design contracted posi units that had clutches all used steel clutch including the chevy EATON posi which is what all the eaton aftermarket units are designed from. The clam shell case design is just plan superior to the track lock unit.
Track lock unit was designed to SAVE metal (money savings in a time when performance was WAY DOWN and money was tight. )
GM never used powdered Metal spider gears.
That a period when you have import parts creating crap parts which have been corrected over many years now.
NOW track lock pinion gear/spider gears that ride on the cross shaft are larger diameter than the EATON factory posi unit from the chevy this was a bad design in the Eaton unit and they would blow apart under track applications and or when the clutches started to wear excessively causing out of spec backlash between the gears.
TIP- I CAN NOT SAY ENOUGH THAT MAINTENANCE IN A POSI UNIT IS ESSENTIAL TO KEEPING THEM RUN LONG AND RELIABLE... LIKE ANYTHING ELSE YOU NEED TO CHECK FOR WEAR AND RESHIM TO KEEP UP DISTANCES BETWEEN THE SPIDER GEARS WHEN YOU ARE RACING OR EXTREME APPLICATION DRIVING. USERS RESPONSIBILITY
Clutches- Steel clutches have always been superior in longevity...BUT also have a noise factor that metal to metal produces. This why GM unit tend to need the additive very often alone with FREQUENT oil changes.
If you are hard burn out guy or drag racing a lot steel clutches are the way to go. PERIOD
If you are road racing, carbon fiber and or composite (like FORD USES) clutches will perform best and keep the rear end quiet fir street use.
WE have experienced on HARD CORE bracket or hot weather drag racing (hot lap situations) that the carbon fiber and Composite clutch material will fail as the carbon fiber is basically a GLUED on material. AGAIN this is under crazy extreme situations...still a rare occurrence.
TRUE TRAC / Torsen Posi Helical worm gear units. These units seem to be the BEST thing. I am testing one now and it has been in the car for 2-3 years now Drag racing street etc. The cases are Forged and hardened...which is superior to the cast cases of the eaton or track lock gm units or aftermarket units. This is probably because the worm gears have to stay put in the unit with out wearing the worm holes.
concerns - longevity on the worm gears, side gears and worm gear holes. I do not believe there are any rebuild parts for these units. SO will they last as long as the units we have now? WILL SEE
All in ALL- it looks like they are here to stay as they are STRONG and work VERY WELL in ALL APPLICATIONS! Road race, circle track, street and drag race.
This is merely a rebuttal to make sure that people are getting unbiased information.
All I do is install rear differential parts EVERYDAY... see parts blow, see installs done wrong and seen parts do incredible things that they were never designed to do, BUT DO IT! (LIKE POSI UNITS DOING 10 AND 9 SEC RUNS)
PLEASE DO NOT GET THE IDEA THAT THIS IS A NORMAL OCCURRENCE - WHEN YOU GET TO THESE ETs YOU ARE FLIPPING A COIN EVERY TIME TO ARE RACING WITH A POSI UNIT. THIS IS WHY WE RACE WITH FULL SPOOL AND BOLT IN AFTERMARKET AXLES!
AND
THE REASON REAR ENDS AND OTHER PARTS ARE NOT WARRANTED FOR RACING.
If you already have a gm trac lock in your rear it will do the job no problem and rebuilding the posi is probably the most cost effective way to go and will hold up perfect.
You still have to remember that some of you may go out and buy a used unit for 100.00 used(remember those spider gears will have 30-40 years of use AND they do not reproduce the spider gears) then put 200.00 (plus shipping?) set of clutches ([B]in this case high quality[/B]) and then some labor 20-50 after cleaning and shimming correctly. Aftermarket units are selling for 375-450 NEW
Please do your home work and make the decision for your application.
Good parts are hard to find and these will certainly do the job in the correct applications also supporting USA made products.
Jim Mitschke
J D
Last edited by monzaz; February 26th, 2013 at 06:11 AM.
Jim
July 5th, 2013, 07:39 PM
#16
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Join Date: Feb 2012
Posts: 13
January 4th, 2014, 08:41 AM
#17
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Join Date: Feb 2012
Posts: 13
8.5 Posi Clutch Kits are in stock and ready for immediate delivery.
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DSCF0702_zps53937bbb.jpg
DSCF0670_zpsa3046148.jpg
DSCF0675_zps7d3c3818.jpg
DSCF0677_zps6a7e5ca7.jpg
DSCF0703_zps8d99bc97.jpg
DSCF0704_zps990a4c10.jpg
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Last edited by 1984 Hurst Olds; November 28th, 2014 at 03:34 PM.
June 17th, 2014, 05:11 PM
#19
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Join Date: Feb 2012
Posts: 13
Hi Rob,
The unit in your 94 Caprice is a 30 spline Auburn cone style unit. The Auburn is not rebuildable. Once it is worn, the Auburn is junk. I recommend an Eaton 30 Spline Posi Unit. The Eaton is very durable and it is rebuildable.
http://www.summitracing.com/parts/etn-19559-010
If you have any questions, please send me a PM.
The unit in your 94 Caprice is a 30 spline Auburn cone style unit. The Auburn is not rebuildable. Once it is worn, the Auburn is junk. I recommend an Eaton 30 Spline Posi Unit. The Eaton is very durable and it is rebuildable.
http://www.summitracing.com/parts/etn-19559-010
If you have any questions, please send me a PM.
June 17th, 2014, 06:03 PM
#20
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Join Date: Jun 2014
Posts: 2
Thanks, thats what I have heard. This confirms it. I recently converted my drum brakes to disc in the rear. When it was put back together the garage put synthetic gear oil in and now no posi, just a burning passenger tire......I think I may drain it and put in straight reg gear oil without the limited slip additive and see if that brings her back to life. I refuse to believe the posi is shot with only 85k on the clock. I mean it was my grandmas car for christ sake
June 19th, 2014, 12:16 PM
#21
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Join Date: Jul 2006
Location: Richfield, Oh
Posts: 1,737
10 bolt 8.5 from 1988-1996 wagons and cars
Hi Rob,
The unit in your 94 Caprice is a 30 spline Auburn cone style unit. The Auburn is not rebuildable. Once it is worn, the Auburn is junk. I recommend an Eaton 30 Spline Posi Unit. The Eaton is very durable and it is rebuildable.
http://www.summitracing.com/parts/etn-19559-010
If you have any questions, please send me a PM.
The unit in your 94 Caprice is a 30 spline Auburn cone style unit. The Auburn is not rebuildable. Once it is worn, the Auburn is junk. I recommend an Eaton 30 Spline Posi Unit. The Eaton is very durable and it is rebuildable.
http://www.summitracing.com/parts/etn-19559-010
If you have any questions, please send me a PM.
Jim
Last edited by monzaz; July 12th, 2014 at 06:16 PM.
August 6th, 2014, 07:35 AM
#24
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Join Date: Sep 2010
Location: Indianapolis
Posts: 4,846
I met Bruce at the Nationals a few days ago & he schooled me & a couple other guys on the 2 12 bolt olds rear ends(TM & SH) I had for sale. He seemed to really know his stuff & I appreciated him sharing his knowledge.
August 6th, 2014, 02:37 PM
#26
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Join Date: Feb 2009
Location: Brazil Indiana
Posts: 11,503
X2. Very willing to explain all our questions. Very glad to have met him.
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