new diff,set up wrong
#959887
03/27/11 01:36 PM
03/27/11 01:36 PM
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Joined: Feb 2004
Posts: 1,012
indiana
mcmopars
OP
super stock
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OP
super stock
Joined: Feb 2004
Posts: 1,012
indiana
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ill probably get booted off here,but what the he//.paid $1,200.00 for a new diff from dr. diff.nodular with 410 gears,had to send it back,backlash was way off.was told he was having hard time getting the 410 to set up correct???so i told him to go with the 391 gear.fast forward,i didnt check it and just put it in.it clunked bad.pulled it out and took it to a local guy.pinion was way too deep,you could hardly turn the yoke by hand,way too tight.backlash was incorrect.was told they were us gears,there was no name on the ring gear???dont know whats up with that.anyway he set it up,backlash is now correct and you can turn it easy.the pinion nut was all boogered up like the incorrect socked was used,we replaced with a new nut.i know a lot of people swear by cass,but i was dissapointed to say the least.cass was very friendly and helpfull,but i would have one set up local if i had to do it over.any way thats all i know,the car drives fine now with no clunk.i quess im venting over, $1,200.00 for a rear that had to be sent back once then sent out to have it re-set.
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Re: new diff,set up wrong
[Re: mcmopars]
#959890
03/27/11 03:21 PM
03/27/11 03:21 PM
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Joined: Jan 2003
Posts: 8,016
Polson, MT
DoctorDiff
master
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master
Joined: Jan 2003
Posts: 8,016
Polson, MT
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Jerry,
I stock Motive and US Gears.
The first set of gears I installed were Motive, because US hasn't made a 4.10 489 case ring and pinion in 3 years.
The 4.10 Motive ring and pinion had a good pattern, but if I set the backlash tighter than 0.012" the pattern suffered. You told me you were running a manual valve body and wanted to run minimal backlash to avoid "clunking like the original third-member had", so you returned the new third-member and I installed a set of 3.91 US Gears (free of charge) which set up at 0.008"-0.010" backlash.
Several months later, on 9/12/10, you E-mailed me:
"I still get gear clash when anything other that full throttle runs. I'm going to go with a cope or a&a transmission this winter with stock valve body with a transgo shift kit (to minimize shift harshness)". You also asked "do you think i can get .06-.08 backlash to help the clunk,clash issues?"
I replied:
"Realistically, I doubt 0.002" tighter backlash will help. It will probably just result in gear howl. You may want to look into the condition of the internal parts in your transmission or driveshaft as ring and pinion lash seldom results in the degree of gear clash you describe."
That was the last I heard until I read this post.
I guarantee:
1. I installed US Gears. They are clearly marked "made in USA" and they have a small shield stamped on the ring.
2. Backlash was set 0.008"-.010". US Gear specifies 0.008"-0.012".
3. Pinion preload was 14-19 inch lbs rolling torque (which is stiff to turn). I also preload carier bearings (also stiff to turn). I do not set new bearings "easy to turn" because whey will run LOOSE when fully broken in.
All these specs are right out of any service manual or gear installation manual.
I would like to know:
1. Did you install any different drivetrain components like you said?
2. If so, what changes did you make (transmission, driveshaft, spool, axles etc...)?
3. Did the third-member I built howl?
4. If you still had problems, why didn't you contact me further?
Cass
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Re: new diff,set up wrong
[Re: DoctorDiff]
#959891
03/27/11 04:37 PM
03/27/11 04:37 PM
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Joined: Feb 2004
Posts: 1,012
indiana
mcmopars
OP
super stock
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OP
super stock
Joined: Feb 2004
Posts: 1,012
indiana
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Quote:
Jerry,
I stock Motive and US Gears.
The first set of gears I installed were Motive, because US hasn't made a 4.10 489 case ring and pinion in 3 years.
The 4.10 Motive ring and pinion had a good pattern, but if I set the backlash tighter than 0.012" the pattern suffered. You told me you were running a manual valve body and wanted to run minimal backlash to avoid "clunking like the original third-member had", so you returned the new third-member and I installed a set of 3.91 US Gears (free of charge) which set up at 0.008"-0.010" backlash.
Several months later, on 9/12/10, you E-mailed me:
"I still get gear clash when anything other that full throttle runs. I'm going to go with a cope or a&a transmission this winter with stock valve body with a transgo shift kit (to minimize shift harshness)". You also asked "do you think i can get .06-.08 backlash to help the clunk,clash issues?"
I replied:
"Realistically, I doubt 0.002" tighter backlash will help. It will probably just result in gear howl. You may want to look into the condition of the internal parts in your transmission or driveshaft as ring and pinion lash seldom results in the degree of gear clash you describe."
That was the last I heard until I read this post.
I guarantee:
1. I installed US Gears. They are clearly marked "made in USA" and they have a small shield stamped on the ring.
2. Backlash was set 0.008"-.010". US Gear specifies 0.008"-0.012".
3. Pinion preload was 14-19 inch lbs rolling torque (which is stiff to turn). I also preload carier bearings (also stiff to turn). I do not set new bearings "easy to turn" because whey will run LOOSE when fully broken in.
All these specs are right out of any service manual or gear installation manual.
I would like to know:
1. Did you install any different drivetrain components like you said?
2. If so, what changes did you make (transmission, driveshaft, spool, axles etc...)?
3. Did the third-member I built howl?
4. If you still had problems, why didn't you contact me further?
Cass
1-new tranny
2-not enough to bother me
3-i wasnt going too ship it back again
im saying this 3rd member had issues, and it was taken care of by a local mopar guy.
these are the issues he found with your setup.and they are now fixed
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Re: new diff,set up wrong
[Re: mcmopars]
#959892
03/27/11 05:52 PM
03/27/11 05:52 PM
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Joined: Jan 2003
Posts: 8,016
Polson, MT
DoctorDiff
master
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master
Joined: Jan 2003
Posts: 8,016
Polson, MT
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Sounds like your guy loosened the bearing preload and tightened the backlash 1 notch. BTW, 0.002" is something like the width of a human hair.
I'm glad 0.006" backlash worked out for you. Most times I've tried it, US brand gears howl because they are lapped at 0.008" minimum and the edge of the ring gear runs slightly in the rough.
Yes, you can run next to zero preload on new bearings. This is not usually recommended because, as new bearings break in, they loosen up. This increases gear deflection and decreses gear strength.
I don't know what to say about the pinion nut. I use an impact socket machined down on the outside so it will fit inside the yoke. Maybe the one I used at the time was getting worn. I have to replace them occasionally.
Normally, if new gears don't howl and new bearings are preloaded without burning, this does not indicate a set-up problem. I may have done something wrong, but unfortunatley, I can't inspect the third-member from here and I can only go by what you tell me.
Thanks for adding you also just installed a new transmission. I have a feeling this was the cause of the "clunk under part throttle" as you shifted the manual valve body in your old transmission.
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Re: new diff,set up wrong
[Re: dusturbd340W5]
#959894
03/27/11 10:27 PM
03/27/11 10:27 PM
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Joined: Jan 2003
Posts: 3,967
S.I. N.Y.
1MYTGTX
master
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master
Joined: Jan 2003
Posts: 3,967
S.I. N.Y.
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Cass has done right by me numerous times & knows his stuff...
FWIW I get a "clunk" from a 2-3 shift from my RMVB if I am NOT into the throttle...I believe it is inherent to the design of the valvebody & has nothing to do with the rear
You can shift 1-2 with no throttle but 2-3 you MUST be on the throttle.
1MYTGTX
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I do not know Cass have never spoke with him or ordered any parts but as someone that has spent 25 years in the transmission business also setting up rears one with .008-.010 back lash WILL NOT cause the clunk you describe.
