Rear Gears

Discussion in 'Got gears?' started by Sir Speedy, Apr 3, 2010.

  1. Sir Speedy

    Sir Speedy Well-Known Member

    Hi Jim,
    The original shim was a .030 with the 3.31 factory gear set. I have a .038 shim in there now. Just took the cover off a little while ago and pattern checked it again like you said with a little oil on the gears and it looks like it's a little high on the tooth and fairly centered slightly towards the heel. I'm thinking it needs more pinion shim. I had read elsewhere on the net that some of these 12 bolts needed .043 shim to get a good pattern. That will probably be what mine needs! I also found the depth checker slightly out of cal., should have checked that first! Going back out to the garage and take some more pics that will fit the format here, pull the carrier out and recheck pinion depth with the tool calibrated properly.
    Thanks again for your input,
    Tim
     
  2. Sir Speedy

    Sir Speedy Well-Known Member

    pattern pics.
     

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  3. monzaz

    monzaz Jim

    Looks much better now BUT your actually a little to deep now. DO NOT go .043 you will be too far the other way again Before you were probably too shallow with the .030

    NORMAL place for almost all aftermarket gears will be between .033- .038 on 12 bolt chevy .035 is always a good place to start when you have NO shim ti start and NO depth gauge to give you a start.

    Pattern Look in the valley. See the straight line across the valley? That means it is just a little too deep. YOU are very close to getting it right on. about .002 off and you should be there. Remember that old pattern is tough to over come now that you ran the gear sin at the old shim spec. The coast side will have a more consistent pattern to reference now.

    What shim did you have when you first set up your 3.73 gears? I nned to know all this as it will help me figure out the correct place for these gears along with these pictures. ok? Jim

    Keep the info coming will figure it out. :) Jim
     
  4. monzaz

    monzaz Jim

    Please look at your pictures I circle the trouble area I see. It is NOT far off BUT will still be a problem. TOO DEEP
     

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  5. Sir Speedy

    Sir Speedy Well-Known Member

    Jim,
    I put the new 3.73 in with a .036 shim based on the depth checking tool and .006 backlash. It was very noisy. The pattern pics are with a .038 shim and .010 backlash and it was much less noisy. I should have kept the .036 and loosened the backlash to .010 and rechecked the pattern. I recalibrated the depth tool and found it was off. Pulled the carrier and recheck depth and it varies between .513 to .519 as I checked several positions around the pinion gear, so the pattern will have to be the final say.
     
  6. Sir Speedy

    Sir Speedy Well-Known Member

    Hi Jim,
    Here are some pictures with a .035 pinion shim and .011 backlash. Let me know what you think. The instruction sheet that came with the gear set shows the pattern opposite of what I know have. This thing is going to drive me crazy! Anyway, thanks again, I really appreciate your help.
    Tim
     

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  7. monzaz

    monzaz Jim

    That is not exactly horrible REMEMBER you have ALREADY run the gears in WRONG...so it will be having some difficulty reading the pattern now. take the backlash and tighten it up to .008 and see what you get.DO NOT change anything else. Ok? Jim

    PLEASE DO NOT CHANGE ANYTHING ELSE just the backlash. remove .003 from the right and add to the left. :)

    Keep going. I am here too. AND I DO THIS EVERYDAY...LOL. :D :Dou: :Dou: :Dou: :spank: :spank: :ball: :ball:
     
  8. monzaz

    monzaz Jim

    Drive side looks much better ... YOU usually can not control where on the gear your pattern will be ONLY how well it will swipe across from top peak to valley.

    JIm
     
  9. monzaz

    monzaz Jim

    Looked back at some posts: .036 you ran the car and it was noisy any chance you did not have the preload on the carrier correct...MAybe a little too loose? Was the carrier able to be pulled out of the housing with a tug? Or did you have to pry it out?

    Also how about the pinion were the bearing preloaded /seated into the cups completely ...just slight drag correct no bearing noisy should be heard when spinning the pinion WITH OUT the carrier and WITH out oil or just a light coat of wd40. ? Just some double check questions. Jim
     
  10. Sir Speedy

    Sir Speedy Well-Known Member

    With the .036 shim and .006 bl it was very noisy. Pinion preload was at 25 inch pounds and turned smoothly but did seem like there was some binding with the carrier installed. When I removed it was able to pull it out by hand, so there probably wasn't enough preload there. Do you think the pattern is OK or should I add more shim? Also, the latest pics are with .011 bl. I'm thinking about pulling the rear end out and bringing it to you, you're about 3.5 hours from me and I am losing my patients with this. Let me know what you think about it. I could be there Saturday around noon. If you could please give me a call 586-524 -5692.
    Thank you,
    Tim
     
  11. Sir Speedy

    Sir Speedy Well-Known Member

    Sorry, I somehow missed your first post after the latest pics before I wrote the above post. I will do what you said this evening and check pattern again and photo for your viewing pleasure....LOL. I cant thank you enough,
    Tim
     
  12. Sir Speedy

    Sir Speedy Well-Known Member

    pattern with .035 shim and .009 backlash. With the shims I have was unable to get it .008.
     

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  13. Sir Speedy

    Sir Speedy Well-Known Member

    Well, decided to go ahead and run the .035 shim and .009 bl and still noisy. I'm thinking either I damaged the gear set on the first set up or I've got a bad set. Four times in and out with different set ups and still noisy. Bearings are all smooth when turning, preload was good on pinion and carrier bearings with third and fourth set ups. I have had enough of this nonsence. Maybe I should have gone with a Yukon or US Gear as Motive is made either in Italy or China. The car will first place in the jack stand nationals for now! :ball: :af: :Dou: Not necesarily in that order!
     
  14. Bad Buick

    Bad Buick Foe Fiddy Five

    I believe Motive Gear is made in Korea.
     
  15. Sir Speedy

    Sir Speedy Well-Known Member

    Yep, you are correct. Talked to DTS and that is what I was told.

    Will be pulling it apart again today. Drove the car to work on Thursday and the gear noise is excessive, especially between 45 and 60 MPH on light throttle. It is OK everywhere else, just very slight noise which is I could live with. May search for a good used factory 3.73 gear which I should have done in the first place.

    When I first talked to DTS the said the Motive gear would be easy to set up and have quite operation. Called them to talk about the issues I'm having and now they say some gear noise may be normal. And get this, if you think you have a defective gear this is how they do it, DTS sends the gear to motive and it gets cut in two to check the hardness, and if you want another gear in the meantime you have to buy it. So, if you do that and Motive says the gear is OK, you just bought two gear sets! Nice. Why would they have to cut it in two to check the hardness? Seems to me they are just being wiseguys about it at that point. Had I been told this before I bought it I would have purchased elsewhere. :Dou:
     
  16. Bad Buick

    Bad Buick Foe Fiddy Five

    What a debacle:Dou:..How many times have you had it apart? Do you put it on a lift? It takes a lot of muscle to crush the the crush sleeve. I think Precision Gear is made in Italy. I only use US Gears or AAM gears.
     
  17. Sir Speedy

    Sir Speedy Well-Known Member

    Tell me about it! Had four different set ups in it and could not get it to an acceptable noise level. Yes it is on a lift I recently had installed in my garage. Talked to the service manager at DTS about it and he said they will warranty the gear after I explained everything I did to get this thing set up. Pulled the housing out this evening and taking it to them to set up and he said we will put a US Gear in it. AAM doesn't make a gear for the 12 bolt. Would be nice if you could get a factory type gear for it and probably eliminate noise issues. The 3.31 that was in it was quite and is from 1970 or so. You can't beat factory parts when it comes to things like this.
     
  18. monzaz

    monzaz Jim

    I just set-up 4.33 richmond in a tremec 5 speed GTO 1965 12 bolt rear...ZERO noise. Then just set a 3.42 Yukon gear...Again NO noise. MAybe just a stinker gear. Better take your time on the next one CAUSE I positive you will not get any more. :)

    Keep that back lash at .008 you should have a nice quiet ride as long as your pattern comes out good.

    Motive gears were made in Italy... I have some boxes still on the shelf from about 3 years ago. This might be some thing new Motive is using now. MOST come from Korea & India...They ARE SUPPOSE to be double check and lapped here in the USA. So AGAIN you can only blame the people selling the item. If the gears are bad they need to go back.

    BUT here is what really happens. If a batch is bad they will usually stile up a deal at a REAL low price and sell them for OFF brand gears...These are the ones that will run ok BUT could have noise issues. Nice HUH? Jim:Dou: :Dou: :Dou: :af:
     
  19. Sir Speedy

    Sir Speedy Well-Known Member

    Took the housing out and dropped it off at DTS to have them set it up with the US Gear, which is made by Strange Engineering here in the USA. Put it back in the car this weekend and it's fairly quite, just hear a very slight whine which I can live with. Thanks to all for your input.
    Tim
     
  20. Bad Buick

    Bad Buick Foe Fiddy Five

    What pinion shim did they wind up using?
     

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