kreed Posted November 30, 2018 Share Posted November 30, 2018 My 66 Riv GS was originally a Positraction 3.42 ( as they all were) . The original owner got tired of the clatter and " had the clutches removed " according to his detailed notes in 1970 with only 6,000 miles on the car. Had my differential guy look into it today and found that the clutches are there but the clutch springs and retainers are gone ( 2 each ) - know this is like looking for a needle in a haystack but would be interested in them if anyone has set laying around ending a new home . Are there any aftermarket equivalents that would fit - my guy seems to think so but this is the first Riviera 3.42 he has looked into ? Any help would be appreciated . Thanks in advance . KReed ROA 14549 1 Link to comment Share on other sites More sharing options...
JZRIV Posted November 30, 2018 Share Posted November 30, 2018 Ken, I am curious - Is there a specific reason you want to reinstall the spring packs? Your noting the original owner was tired of the chatter even when the car was new is evidence of how prone they were to chatter. Link to comment Share on other sites More sharing options...
kreed Posted November 30, 2018 Author Share Posted November 30, 2018 The way it is set up now it is definitely not a Positraction and I want to put it back to the original way it should be - my OCD I guess . Any suggestions ? Thanks Jason KReed ROA 14549 Link to comment Share on other sites More sharing options...
JZRIV Posted November 30, 2018 Share Posted November 30, 2018 (edited) So you have attempted to do a burn out and only one wheel is spinning? You should DEFINITELY still have posi without the preload springs. Its my understanding the preload helped in more extreme situations such as when one wheel was on ice/snow and one on dry ground. The force applied to the clutches under torque by the design of the side bevel gears puts a lot of pressure on clutch packs to lock them. Under load and not in extreme traction differences between wheels, the springs really do nothing. I removed the preload springs in mine because I got tired fighting it. None of the typical oil additives worked. I had it apart twice and the clutch plates were in great shape and could find no problems. Still leaves two black marks Edited November 30, 2018 by JZRIV (see edit history) 1 Link to comment Share on other sites More sharing options...
steelman Posted November 30, 2018 Share Posted November 30, 2018 Try these. https://www.justdifferentials.com/category-s/3032.htm http://www.eaton.com/us/en-us/catalog/differentials/eaton-posi-differential.html Link to comment Share on other sites More sharing options...
telriv Posted November 30, 2018 Share Posted November 30, 2018 Kreed, The 1st. thing I WOULD DO is to go to your local GM dealer & get two bottles of their POSI additive. Then put it in & do MANY figure 8's in a large parking lot to see if that helps clear up the CHATTERING/BANGING. You need to get the additive mixed with the gear oil & between the clutch plates. I know that Jason did this & wasn't satisfied with the outcome which is why he REMOVED his springs. Just my suggestion. Tom T. Link to comment Share on other sites More sharing options...
kreed Posted November 30, 2018 Author Share Posted November 30, 2018 Definitely not posi- jacked up rear end . Only one wheel moves at a time when you rotate either . There is a stack of alternating clutches and shims on the right side and ?..a few shims on the left . Haven't pulled it out completely but my friend who is the differential specialist says the clutch springs and retainers are definitely not there and that is definitely NOT a posi at this point . This discussion is quickly getting above my pay grade as I know nothing about these sorts things ( but willing to learn) . As I told him , I would be glad to to show up how to take out a colon cancer if he would show me how to fix a Positraction rearend - the colon resection is much easier !,😃😃) . Will check out Steve's suggestion . Thanks everyone KReed ROA 14549 Link to comment Share on other sites More sharing options...
JZRIV Posted November 30, 2018 Share Posted November 30, 2018 Ken, Sorry if I am belaboring this because you just ask a simple question for a preload spring source......but I want to understand exactly what's going on. When you say only one wheel moves at a time when you jack up rear, hopefully at a minimum they are both moving but perhaps in different directions like a standard open differential? Even with preload springs removed on my car there was still enough friction between clutches to make both wheels turn in same direction when doing the static test with rear end raised and trans in neutral but its possible there may not in yours and it will appear as an open differential in the static test. That's why I asked if you did a burnout because doing so loads the clutches to lock them for posi action the instant torque is applied. When testing by doing a burnout, its much easier on the Riv to do a burnout in reverse while on a slight incline nose down of course. As I recall you had posted about having chattering problems several months ago so at this point I assume no shims or clutch plates were removed by the PO. If that chatter has not been eliminated 100%, there is good probability chatter will return if preload springs are installed. Link to comment Share on other sites More sharing options...
1965rivgs Posted November 30, 2018 Share Posted November 30, 2018 PRELOAD springs are aptly described. These springs preload the clutch plates against one another before the torque input of the driveshaft does so. I can see why the wheels would not respond as expected without the preload springs but having stated so I have never removed the springs and checked for behavior. However, the same behavior is exhibited when the clutch plates are totally worn out so this makes sense. The best method to determine whether the diff is acting as a posi is to do what Jason suggests and load the diff via the driveshaft. Tom Link to comment Share on other sites More sharing options...
kreed Posted December 1, 2018 Author Share Posted December 1, 2018 12 hours ago, JZRIV said: I recall you had posted about having chattering problems several months ago so at this point I assume no shims or clutch plates were removed by the PO. If that chatter has not been eliminated 100%, there is good probability chatter will return if preload Jason - I actually have two 66 GS - a "beater " (black one that I got ripped off on an EBay purchase about 3 years ago - lesson learned) that my differential guy just finished with new clutches and now behaves as it should . My other GS (riviera red with 15K miles ) is the one I am currently discussing . He ordered some aftermarket pre load springs and retainers today that he thinks will work and so I will keep you posted . Thanks for all the discussion and help . KReed ROA 14549 1 Link to comment Share on other sites More sharing options...
kreed Posted December 6, 2018 Author Share Posted December 6, 2018 Problem solved ! Here's what my differential guy did (and this is his description ). " We installed standard Eaton #400 springs and retainers into the 9 3/8 posi unit . Also when we loaded the clutches , we removed one splined clutch on each side and replaced it wirh a standard separator disc. This brought our rolling preload yo 70ft/lbs . To be clear we still had a total 18 discs in the differential . We just removed two splined discs and replaced them with two spacer discs . If you want a more aggressive preload you could leave all 8 splined discs in the mix , but the car may let you know it when turning tight slow speed turns " i watched him do it - fascinating stuff - learned a lot about real dirty work . Drove it afterwards - perfect in all aspects . If you have questions , send them to me and I will pass it along to him KReed ROA 14549 1 Link to comment Share on other sites More sharing options...
kegart Posted December 6, 2018 Share Posted December 6, 2018 That is a nice looking beater Link to comment Share on other sites More sharing options...
RivNut Posted December 6, 2018 Share Posted December 6, 2018 Beater is relative to the other cars in your coral. Perhaps Ken will post a picture of his silver 72 boat tail for us to oggle over. Link to comment Share on other sites More sharing options...
kreed Posted December 7, 2018 Author Share Posted December 7, 2018 The " beater " is a twenty footer for sure . When I bought it , the seller said the paint was 7-8/10 . When it arrived , it looked it had been painted in a Kansas sand storm (2/10 and lacquer ! ) . It's in the queue for paint job , hopefully this Winter . KReed ROA 14549 Link to comment Share on other sites More sharing options...
kegart Posted December 7, 2018 Share Posted December 7, 2018 I saw your boat tail at Overland Park. What a great car. How many Rivieria's do you have? Link to comment Share on other sites More sharing options...
kreed Posted December 8, 2018 Author Share Posted December 8, 2018 Thanks for the note - I have a 63, 64 , 65 GS , 2- 66 GS, 67, 69 GS, 72 and 73 GS - love them all - each with a different " personality! Looking for a nice 68 GS . KReed ROA 14549 Link to comment Share on other sites More sharing options...
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