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72NOVA454
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Discussion Starter #1
Guys, I need your help. I don't know what to do.

This is for a GM 10-bolt 8.5 inch setup.

I'm in the middle of redoing my backend of my 72 this winter. I brought my new carrier, ring & pinions, installation kits, etc to a local transmission shop to have the new ring gear pressed onto the new carrier, and the old pinion shims removed from the old pinion to possibly reuse and check it's thickness. I was going to take those parts back home when he was done and do the ring/pinion setup myself. He offered to do the entire setup himself for a very good price. I accepted.

I picked the assembled axle housing up from him and when I got home checked tooth contact pattern. It's not "ideal" like it shows in many contact pattern instructions. The drive side pattern is to much towards the "toe" of the tooth. It is not in the center. The centering between the tooth flank and root seems to be ok though. the tooth coast side pattern appears to be ok. Backlash measures .012". Richmond gear says it should be .008". But again all contact is at the "toe" end of the tooth.

I called the guy at the shop and complained about the tooth pattern being to much "toe". He said he has done "a couple hundred" of these and never had a problem. He says he used a instrument to set the "checking distance" or "pinion depth" as inscribed on the pinion from Richmond Gear and then adjusted backlash after that and that "it's right on" and should be fine.

what should I do? Should I just move forward with the installation of the housing or should I have it done all over again until the pattern is "ideal".

Lee
 

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72NOVA454
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Discussion Starter #3
I will try to find some tooth marking compound at a local shop if I can. then I will mark the teeth again and post the contact pattern on this site by tomorrow hopefully.

do I have to use tooth marking compound or is there something else I can use.

Lee
 

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Sometimes using never seize will give you a pattern. The gear marking compound works the best. Either way, if you squirt a little trans fluid on the gear where you have the marking grease, you will get a much clearer pattern on the gear tooth.
 

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72NOVA454
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Discussion Starter #5
here are pics of the tooth contact patterns. both the coast and the drive sides.

is this good enough to remain as is or should I have the entire setup redone again.

lee
 

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It doesn't really matter what the pattern looks like right now because the backlash is out of spec. It should be .006-.010" and it is at .012" :pain:
 

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72NOVA454
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Discussion Starter #7
Triaged said:
It doesn't really matter what the pattern looks like right now because the backlash is out of spec. It should be .006-.010" and it is at .012" :pain:
sounds like I have to do the whole thing all over again then. what a pain in the ***. Everything is done, crush sleeve, pinion nut, etc.

what a mess.

I paid that guy couple hundred bucks to do the setup and it's not right.

very frustrating.
 

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Hotrodders.com Moderator
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r&p

Just the fact that the backlash is .004" over the max is a big red flag to me...

Some old racer guys will set the contact pattern low on the drive side to allow for flex under load when the pinion rolls up on the ring gear,,,but thats not the case here because if he was doing that trick the back lash should be around.002"

Don't pay much attention to the coast side..the last 4 or 5 richmonds i have set up were out to lunch on the coast side... None of them make any noise....

But you should get the contact patteren correct on the drive side and set the correct backlash...

I wonder what kind of pre-load he has on the pinion bearings if he can't get something easy like the backlash correct????


keith
 

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72NOVA454
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Discussion Starter #9
k-star said:
Just the fact that the backlash is .004" over the max is a big red flag to me...

Some old racer guys will set the contact pattern low on the drive side to allow for flex under load when the pinion rolls up on the ring gear,,,but thats not the case here because if he was doing that trick the back lash should be around.002"

Don't pay much attention to the coast side..the last 4 or 5 richmonds i have set up were out to lunch on the coast side... None of them make any noise....

But you should get the contact patteren correct on the drive side and set the correct backlash...

I wonder what kind of pre-load he has on the pinion bearings if he can't get something easy like the backlash correct????


keith
I don't know what he did with the preload setting (typically 20-30 in/lbs) I'm very pissed off now - ready to punch a wall. I'm $200 in the hole and a week behind schedule and will likely have to do the whole thing over again. I don't want that guy doing it again - that's for sure.

Lee
 

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Hotrodders.com Moderator
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rear

I totally understand..

IMO the best deal is to cut your losses and fix it your self... Then you know for sure it's done correct....

That typ of workmanship,,, started me doing all my own stuff at the age of 17....L.O.L.

Let us know if we can help you out.


Keith
 

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72NOVA454
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922 Posts
Discussion Starter #11
k-star said:
I totally understand..

IMO the best deal is to cut your losses and fix it your self... Then you know for sure it's done correct....

That typ of workmanship,,, started me doing all my own stuff at the age of 17....L.O.L.

Let us know if we can help you out.


Keith
yes I agree. I do 90% of the work on the car myself, chassis, suspension, engine, electrical, interior, etc (I'm not good at sheet metal work though). This was the 10% area where I have people help me and look what happened. I'm not a happy camper.

I somehow have to remove that pinion nut now - torqued down to like 400 ft/lbs, then have the pinion bearing pressed off, reshim it, get a setup bearing (honed out) that I can use over and over again without using a press each time.
 

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Hammer and a torch
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leejoy... Man I thought you were going to do this yourself...? That sucks the guy did a poor job and charged that much too...

Just a thought... If you can do basicly that 90% you mention then hey dont be afraid of 4 bearings and 2 gears... From what I gather you could do a 10X better job than that ya-who did... My main thought as a mechanic when working on just about anything is... :thumbup:

If an engineer can build it then I can take it apart and fix it...
 

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72NOVA454
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Discussion Starter #13
Bumpstick said:
leejoy... Man I thought you were going to do this yourself...? That sucks the guy did a poor job and charged that much too...

Just a thought... If you can do basicly that 90% you mention then hey dont be afraid of 4 bearings and 2 gears... From what I gather you could do a 10X better job than that ya-who did... My main thought as a mechanic when working on just about anything is... :thumbup:
dear bumpstick.

thanks for the words of wisdom and your support. I agree with all that you said. I'm not afraid of doing it myself. It's just the pinion bearing and shim that concerns me, and the torquing down of the crush sleeve (400 ft/lbs). I will have to have a "setup" bearing to use to setup the whole thing because I don't have a hydraulic press to keep removing the pinion bearing over and over again to change the shim. So I would have to buy another bearing, hone it out and use it as a "setup" bearing. but that concerns me too. The setup bearing may not be exactly the same as the "permanent" bearing. So I am a little reluctant to do this whole thing. Once that crush sleeve is crushed and it's all back together, if the permanent bearing is not perfect, the contact pattern will be screwed up again. If I did it myself, I will need a new crush sleeve, contact pattern compound, setup bearing, honing tool, more pinion shims, and a impact wrench. So even if I do it myself I have a bunch of stuff to get. Se what I mean.

don't laugh but....... I don't have a impact wrench - yet. It's time to go out and get one now I guess.

I found another place today (atomic transmissions) that I stopped at. He said he will look at if for free and help me out and make recommendations. I need to bring it to him he said. It's a huge trans shop (one of the biggest in the country he said) that advertises in the local hot rod newspaper around here (gearhead news). If this other place can do it (and do it right) for like $150 to $200 that's fine with me. If they want more than $200 I'll do it myself.

I'll think about it.

this sucks.

Lee
 

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I know you are not satisfied with the rear, but just how did you check the backlash? If you check it in one place it will not be that dimension all the way around!
I check backlash in 4 places 90 degrees apart and average. Also I use a mike to set pinion depth.
Now if you don't have the appropriate tools :confused: to check it, there is a chance that the thing is set-up close, If it were me and I'd have paid that much I'd run the muffker and see what it does! You could run it a short period and see if it makes any noise, etc.
That's my personal opinion :D
 

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I tend to agree with the last post. If the backlash is only out .0004" than thats
little or nothing, thats hair thickness when it comes down to it !

Its entirely possible that your gauge or method of checking is not correct
so you are not seeing the desired specification.

Is you gauge calibrated to a Nist standard ?

><
 

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72NOVA454
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Discussion Starter #16
guys

thanks for those latest replies. It really helps a lot.

I checked backlash in two places, about .012" in both places. The ring gear is marked .008" from Richmond gear.

Did you see the drive side contact pattern? It looks way off to me.

question: what damage or problems might I see if I decide to run the gear setup the way it is?

will it fail prematurely?

will it be noisy?

will there be a loss of efficiency and power transfer?

will it do permanant damage to the ring gear or pinion

thanks.

Lee
 

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leejoy in my Richmond gear installation instructions it says to" maintain a tolerance of .oo4.if the backlash is.008,the backlash-including maximum variation- should be .008-.012." it also says measure in 3 or more places.It is within Richmond specs :thumbup: I would run it.
 

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72NOVA454
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Discussion Starter #18
DOUBLEDICK said:
leejoy in my Richmond gear installation instructions it says to" maintain a tolerance of .oo4.if the backlash is.008,the backlash-including maximum variation- should be .008-.012." it also says measure in 3 or more places.It is within Richmond specs :thumbup: I would run it.
Dear Doubledick:

thanks so much for your help. I understand and appreciate your comments regarding backlash and will take them into consideration.

But....what about the tooth contact pattern? does that not matter? It does not look correct. It's supposed to be centered in the teeth, not at the "toe" end like it is.

Lee
 

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leejoy your pictures of the gear pattern looks very close to the pictures in the Richmond installation instructions.I have to go to work now but when I get up tomorrow I will scan that page of the instruction book and post it so you can see.It looks very similar to the pattern on my rearend posted on the first page of my '55 to 59 truck owners"thread.I have 5000 miles and 2 burnout contests on that rearend and I pull a trailer with no problems or noise.
 

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Sloe Lurner
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193 Posts
send me your address

I have all the parts you need. I have several crush sleeves and probabally all the shims youll need. I was going to do this myself so I bought extras. Then found a buddy at work who used to do it for a living and still does it on the side for his 4X4 buddies. I'll ship you everything for the price of postage..let me know if it would help!! :thumbup:
 
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