james_adams2006

This is my first gear swap I've done and I hate to ask since so many do, but could someone with experience take a look at my pattern and help me in the right direction?

I've played around with the pinion shimming from too deep to too shallow and this is probably the best pattern I've gotten so far.

Its a set of Richmond 4.56's. It is set at 0.009 backlash (0.010 is whats etched on the gear) and 0.030 pinion shim. It looks to me like it should go maybe a tho' or two deeper, but I'd like someone to back me up on that I'm reading it right.

Any help would be greatly appreciated.

camaromike222

I've done three 10 bolts, and IMHO, a .001" or .002" more shim, like you first suspected, would do you good. The pinion seems slightly far away. You'd be surprised at how much a .001" will make a difference. The backlash looks good IMO.

james_adams2006

Appreciate the response back. Yeah I found that it doesn't take much to drastically change the pattern. I started out tryin the original shim of 0.035 and it was way to deep so I went the other way to about 0.028 and it was to shallow, so now I'm zeroing in on it. It also took me a few trys to get a good pattern to show up but I feel after trying a couple setups I'm getting better at it.

Also, could anyone tell me why it would make a light popping noise (almost like you were rocking the pinion in the backlash range against the ring gear) when I turn the carrier in the reverse direction (to achieve the coast pattern)? It doesn't do it forward. Thanks.

big gear head

You are very close. Are you setting the pinion bearing preload the same each time you check it? The preload needs to be set to the same number as you would for the final assembly. I would add about .001 or .002 to the pinion shim and check it again. If it gets worse then go back to what you have now. Are you using an axle to turn everything when you check the pattern?

james_adams2006

Yes I am using an axle to turn the carrier with. I didn't know if it may be a slight knock of the inner pinion gears since the other axle is not in when I'm turning it over. I'm attempting to set the preload about the same each time. I don't have a inch pound dial torque wrench (I know I should be using one but don't know anyone that has one and couldn't justify spending 300 bucks on one), but I read from another source that the preload is in the approximate required range if you turn the pinion by hand with a good twist and it takes 1/2 to 1 full rotation to stop spinning so thats what I've been going by. I can say that everytime I've reset it up the pinion feels like it is always at the same preload and stops spinning at about the same position when I twist with about the same amount of force. I know this is not a very accurate way to do it, but it's all I have to work with.

big gear head

If you are using new pinion bearings then that is way too loose. When the preload is set correctly you should not be able to spin it at all. It will have quite a bit of resistance to it. Check with a bicycle shop and see if they have a cheap preload gauge that you can get, or rent from them. Setting the preload is pretty important.

onebad82z

iTrader: (7)

You have the best giving you advice. BGH is the man on gears. Listen to him. And not that I am in any league with him, but I agree to get the right tool to measure the torque. I bought a dial inch pound TW when I started installing gears. PM me an address and I will ship it to you to borrow if you guarantee I get it back in the same shape? I will ship it out tomorrow and have it to you by friday. I am impressed by what you are doing with the trans and rear and would like to help ensure it all comes out right so you can fully enjoy it!

james_adams2006

Yes I'm using new pinion bearings.... its been a beast pressing the head bearing on and off every time I change shims and I know there are ways around this (honing a used bearing, etc.), but I haven't messed up the bearing at all using the proper separator and a press... just takes extra time to do. I figured some one would say to use the dial gauge and I knew in the back of my head I should be using it too to make sure it is what its supposed to be. I really want to get this right the first time and not have to go back in it due to an issue such as worn bearings due to preload or messing up a good set of gears due to wrong gear mess.

I will look around and see if I can locate one or maybe find one used off ebay. I really appreciate the offer onebad and if I can't locate one, I might take you up on that offer... but I'm really the kind of person that likes buying the proper tools to use even if I only think I might use it once. You never can have to many tools and never know when you might use them again.

I read a through a couple threads and saw BGH gives some great advice. I was definately hoping he was going to chime in and give me some insight. I really appreciate the help guys and I'll get back with you onebad about the dial inch pound TW.

james_adams2006

Just to let ya'll know I broke down and ordered a dial torque wrench today so I'm going to hold off doing anything else with the rear til I get it and can verify my preload is checking out on the pinion before I progress any further. Give me a few days and I'll post some new pattern pics once I verify my setup now. I have some other smaller things I still have to do with the transmission (wiring, floor shifter boot, make a shifter, etc.) to tackle anyway so I'll work on these until I get the torque wrench.

big gear head

I think you are going to be surprised at how tight 17 to 20 inch pounds of preload is.

james_adams2006

I got my torque wrench yesterday so planning on working on the rearend some today. I hope to be able to get up some new pictures of the pattern with verified pinion bearing preload and hope to get this thing wrapped up today.

james_adams2006

So got it set up again this time verifying a 25 inch/lb preload on the pinion. I have to admit that 25 inch/lb is a lot tighter on the pinion than I thought it was.

This setup is with 0.031 pinion shim, 0.009 backlash. It seemed to look pretty good to me. What do ya'll think?

Sorry if the camera quality is a little crappy. Its all I've got to work with.

big gear head

The pattern is a little off. I would start by changing the backlash and see what happens. The pattern is too far on the heel on the coast side, and too far to the toe on the dirive side. It is centered pretty well from root to face, so the pinion depth is pretty close. If changing the backlash doesn't fix the problem then go back to changing the pinion depth untill the pattern centers a little better between the toe and heel. I would also not go to 25 inch pounds of preload on the pinion bearings. I would try for around 19 to 21.

james_adams2006

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james_adams2006

Here's my next attempt. Its same pinion shimming (0.031) with 0.010 backlash. It seemed to make the contact pattern on both faces longer, so not sure if its good or if I should shoot for around 0.012 or so to see if that makes it better. Let me know what ya think.

big gear head

That did help. I think I would run it like this.

james_adams2006

I may try to shift the ring 0.001 more out of the pinion if I can get my shims to add up right to be able to do that and if it is maybe slightly better. If not then I'll leave it where its at. I thought it looked pretty good as well and the pictures really don't show it up well but it has a better contact pattern than what can be seen in the pictures. I may play around with it this afternoon and go ahead and put the crush sleeve on and check it one final time.

I really want to thank you for your help. This has been a great learning experience and having someone that can review and help guide me in the right direction has definately gave me some good insight as to what to look for the next time I set a rearend up.

james_adams2006

I also have one other question. I bought a summit cast diff cover to help stiffen up the caps in the rear but it doesn't have a magnet in it. Should I take the magnet of the old cover and epoxy it onto this cover? I really think it would be a good idea, especially during break in, that the magnet would help to catch any minute particals that may produce. It wouldn't be a problem to take it off and JB weld it to the inside of the cover, I'm just wondering how necessary it would be.

big gear head

I usually put a magnet on the cover of all the rear ends that I build, unless it is a completely stock rear end with a standard differential. I buy craft magnets at Lowe's and epoxy them to the cover on the lower side away from the ring gear. You will break the original magnet if you try to remove it.

RBob

iTrader: (1)

Check the drain plug, may already have a magnet in it. Although, it never hurts to add another.

RBob.

james_adams2006

Finally got the rearend all back together. I ended up leaving the pinion shimming the way I had it and opened backlash up to about 0.012. It did shift the patterns both closer to the center but never to the point they both were dead center. Still looks similar to my previous pattern at 0.010 just slightly closer to the center. I figured I'll run it there and see how it does. I also figured since it is a mostly street driven cruiser that it may help to have the backlash a little more open to cut down on heat build up so.

I also epoxied two 3/4" diameter magnets to the inside of the diff cover. It did have a small magnet on the drain plug but I figured a little extra security couldn't hurt.

I also found out after I had installed the carrier (what I thought was the last time) and had checked everything I was going to put the axle shafts in. Well I found out that I could not get the cross pin out. I had put the new cross pin in early on to keep anything from shifting and had installed the gears but never tried to take the pin back out. So I had to pull the carrier back out and I know it probably wasn't the best way, but I lightly clearanced the tooth that the pin was hitting on the ring gear preventing it from coming out. I used a thin cutting disc and the grinder and went really slowly never putting much heat into it (I could always touch the tooth after working on it a little bit) as to not destroy the heat treat. I didn't have to take off enough to get down to where the contact pattern was and didn't have to come out far on the face of the tooth. I tried to knock any sharp edges off and cleaned it up afterwards. I'm hoping that it will be ok. Do you think it would have hurt anything?

big gear head

I've done the same thing. There are after market shafts that have a flat ground on them so that they will come out far enough to get the c clips on and off. So there are at least 2 ways of doing this. Some gears are so thick that you can't take enough off of the tooth to get the shaft out. I've had to grind the teeth on 9 inch Ford gears to clear the pinion pilot bearing boss. That's a lot of fun.

james_adams2006

Thats nice to know that someone who does rearends often has had to do this before two. I only had to take off about 0.020" or so to fully clear by a couple thou. I could have done the pin but then I would have had to put a flat down the whole side to be able to get it all the way out. Its an aftermarket pin and already has the large flat in the center area but it wouldn't help clear the gear. Also I didn't really want to have to take the ring gear back off to get the pin out to be able to put a flat on it so I just did it to the tooth. I was just worried about possibly weakening it any. Have you ever had any gears fail that you had to clearance this way?

big gear head

No, it wil be fine. You didn't hurt anything.

james_adams2006

I've put about 250 miles or so on the car since I got it back running. For the most part the gears don't whine when you have pressure on them (on the throttle), but it seems when you let off the gas (coasting) it has a higher whine to it. It does that at 60 and seems ok for the most part, but the other day I passed someone and got up to about 75 or 80 and it was fine as long as I had pressure on gears but when I let of the throttle to coast back to a slower speed it had a pretty loud moan to it and you could feel vibration from it. Now I know its going to make some noise and I do have a heim joint on my torque arm now that would cause to feel more vibration, but I really dont' think it should be as loud and vibrate the way it did. Is it possible my pattern mesh still isn't right? From looking at the pictures I believe the coast side was not centered completely and it did have a little pop to it (thought it may have been backlash play) when I turned the axle in reverse during assembly. Could it be I need to get the coast side to mesh better?

big gear head

Your pattern looked pretty good to me. You could play around with it a little more if you want, but a 4.56 Richmond is probably going to make some noise.

james_adams2006

Alright. I can deal with it whining as long as I know there's nothing wrong. I just don't want something to be wrong and ignore it thinking there's nothing wrong. I figured the heim on the torque arm mount would magnify any noises and minute vibrations coming from the rear anyway so that could be part of it as well. I might later switch to a Del-sphere joint to try to dampen out the noise but the heim was what I had to work with now so. But thanks for some reassurance.

big gear head

It should be fine as long as you got the bearing preload set right so that nothing can move around.

james_adams2006

Bearing preload was good. Pinion was around 22-23 in/lbs and I used shims to on the carrier to equal the same thickness stackup as the original ones.