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Had a set of 4:56 gears installed today. Just got home and reprogramed the ratio and so far it is great. My installer said I would not need to mess with the drive line and he was right. I cannot tell any differance in the noise. He did not use a Motive gear as he does not like them. As today is my birthday it is a great present.
 

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Russ04: What brand and part number of gears did your installer use? This would be really helpful to the other guys on the website.

The Motive Gear ring and pinion my installer used DO make some noise. The installer is going to recheck the backlash clearance next week, but if your gears came out quiet the first time, that's a big plus.

You will enjoy the new gearing a lot. It transforms the vehicle, not just under hard acceleration, but also in the way it feels "nimble" now under all conditions.

Jim G
 

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Jim G I just took it out and tried it after I changed the perimeters and it is awsome. I think the gears were Kodiaks. I will find out tomorrow and post the info. I had it up to 80 without the radio and absolutly no differance in the noise. Very responsive in the lower gears. Even at 75 it cruises very nice. Thanks for all of the leg work. Your data made up my mind.

Russ04
 
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>>He did not use a Motive gear as he does not like them.<<

Weird, my guy says the same thing. He does the gearing for all the off road guys in town that tear up gears in mud pits and such, so I'm going to have to go with his recommendation. I'll be doing mine as soon as I can get scheduled with him. Ground Force kit is going on this week...
 
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Russr04, enjoy your birthday present!

I got my Ground Force springs on today, and the gear set goes in Monday, if the weather isn't too bad. I ended up with Richmond gears...results and P/N to be posted
 

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Thanks all had a great birthday. I also have the ground force on and you will be happy. The gear set my installer used was a Yukon BM8.5-456 He got them out of Oregon. He said he set them at about .003.

Russr04 : :) :) :)
 

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Russ04: That 0.003" is significant. The Motive Gear recommendation was 0.008" target, and 0.006" minimum.

COULD be the difference.

Jim G
 

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Reluctor Plate?

On my 1995 Impala SS you have to change the "reluctor plate" in the rear end when you change to lower gears for the ABS to work properly. Stock gearing on the SS is 3:08 and you can go to 3:73 because there is a reluctor for the 3:73 gears. Can't go to a 4:11 or 4:56 since there is no reluctor for the those gears. Reluctor cost is about $12.00. When you buy a 3:73 change "kit" the reluctor is included. Does the SSR require this reluctor when you go to 4:56 gears, and if so, are they available? I don't know exactly what this reluctor is but I do know it affects the ABS system. Does this make sense to those who are more knowledgable about Chevy rearends? The Impala SS owners site is where I read about the reluctor and the necessity to change it when you go to lower gears.
 
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Jim, My shop mechanics and sales guys tell me the secret is in the face beveling and finish. The more expensive gears use several extra stages of finishing and machining, which is why they cost more. You DID order the best Motive part number, but I know they strongly recommend another part # to go WITH that gear set - and sorry I don't remember what it's called or the part number - but I have both at my shop...will be there on Monday
 

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psychoslaphead: What is the physical part that would "go with" that gear set? I thought you buy just a ring and pinion set, and adjust for correct clearance via shims. Is there more?

Jim G
 
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Thought so too. Motive called for another part to be installed with that gear set -I saw it in my sales guys notes from his discussion with them. Since we ended up going with Richmond, I'm afraid I didn't pay close enough attention. I'll call my guy at the shop tomorrow and get the part name and part # for you.
 
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Jim,

It wasn't any big deal after all, it was the Motive part number for a new crush sleeve and gasket to go with the gear set. Hopefully your guy installed a new one, but since they're a pain to install, some guys don't, but my guys say this is a no no...

- psy
 

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He DID do all new small parts.

I think the issue comes down to Motive specifying a target 0.008" and minimum 0.006" backlash clearance.

Notice that Kodiak apaprently specified 0.003" clearance. That would make a big difference in noise level.

When I talked after the install to the Motive factory tech service rep on the phone, complaining about the audible noise, he said that while there IS going to be more noise with 4.56 than with 3.73, it should not be objectionable in volume. He said not to go tighter than 0.006" on clearance, in order to ensure that the gears are not so tight that they bind when get they hot (e.g. sustained high speed or sustained load), as they get larger when they get hot. In other words, more clearance is safer while being noisier. He said that what sometimes occurs is that the clearance gets a bit larger as the gears break in, and advoised that we should re-check it now, and if necessary, reshim to get back to target, or minimum (but no tighter).

He DID say that if the gears were not properly clearanced by the installer, or were not properly broken in, they COULD have been damaged, and thus be making noise (like a worn rear end would do). But the sop that did the work is one of the 2 best in the Atlanta metro, builds highend engines, and has done rear axle changes a LOT for over 20 years, and the work was personally done by one of the owners (Lamar's son Rob) so I doubt there is an expetise problem. Rob also told me he broke the gears in on the dyno at moderate loading for 40 minutes.

The Motive tech guy's theory about the clearance increasing makes some sense, as my noise gets completely inaudible when the vehicle has run maybe 10 miles at high speed or into a good headwind, but never gets quiet arpound the city at low speeds, even after prolonged use. My theory is that when the gears get HOT, they get to the ideal clearance, so a bit less clearance than what we ACTUALLY have now is probably the right clearance.

At any rate, the feel and performance of the SSR are SO improved with the gear swap that there is no way I would consider undoing this mod, noise or no noise.

Note that the noise I am getting is mostly masked if the AC fan is set to 3 or higher, and completely masked by any sound system volume at all.

Jim G
 

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Discussion Starter #16
Jim G
The gear set I used is a Yukon. I told you it was a Kodiak. There decal has a Kodiak bear on it and I boo bood. The only extra part that I know of is they order a master install kit which has all of the shims and seals. I took it out last night and I have asolutly no noise. I swear I can not tell the differance from the 3:73 as far as noise. My mech told me our rrear end is also has a transend system. (I think that is what he called it.) I will confirm. Any way he told me it is a high end system that messes the gears and gets the most hp to the wheels. He also told me he was suprised to see it when he pulled the gears. They are only put on high end rigs. The rear end is the same as the Yukon as far as matching up the gears. No relucter plate is neccessary.

Russr04
 

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russr04: Yes, we have a "Torsen" differential in our SSRs.

Torsen is short for TORque SENsing.

It is a very sophistcated system, far better than the clutch type limited slip differentials found in most vehicles.

Another vehicle that has one is the Mazda Miata.

Your comments on no noise encourage me. I think it's just a matter of getting the right adjustment.

Jim G
 
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Jim, I'll let you know how mine goes as far as noise next week. Is it a whineing sound you're hearing or something else?
 

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Discussion Starter #20
They will get it down. Like you said the differance in preformance is still worth the extra whine. I am very impressed with the extra get up and go. Very noticable differance. Good luck. Keep us posted

russr04
 
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