Gear Pattern Good?

[90FoX]

What's up guys? Just setting up my old gears after rebuilding the rear on the stang and wanted some input on the pattern I have.

Pinion depth, backlash and preloads are all correct.

These look pretty good to me but this is my first time doing gears so I wouldn't mind some input :loser:

Drive Side

Coast Side

Drive side pattern on unpainted teeth

Coast side pattern on unpainted teeth

She's been down since the end of dec and I want to get her out for some sun now.

Thanks fellas :beer:

 

[cmr98cobra]

Not trying to be a dick... But how do know your pinion depth and backlash are correct? Because your paterns don't look right, Especially the coast side the drive side needs more tension on it while rotating... what that means is when you turn the pinion flange have a helper use a small pry bar on the diff to fight the direction your rotating.

But back to the coast patern... notice how it has a clearly defined triangle, their should not be any sharp edges in the pattern. It should look like the blue oval logo. Most likely the pinion depth is off.

Keep tring and good luck, but this is one place that you can not just slap it back together and say "good enough for goverment work" just a couple of thousands of an inch make the differance between a noising set or damage and perfection.

 

[PACIFICGREENSVT]

That looks good. one trick I know of is to use or try your old pinion shim first. saves some time.

 

[CJK440]

I agree with CMR. Ideally there should be no hard edges, the perimeter of the pattern should feather out in all directions.

But in the real world you are going to be hard pressed to get a textbook pattern, just a best case.

If it were me, I'd make some minor changes and see where it goes.

 

[90FoX]

Not trying to be a dick... But how do know your pinion depth and backlash are correct? Because your paterns don't look right, Especially the coast side the drive side needs more tension on it while rotating... what that means is when you turn the pinion flange have a helper use a small pry bar on the diff to fight the direction your rotating.

But back to the coast patern... notice how it has a clearly defined triangle, their should not be any sharp edges in the pattern. It should look like the blue oval logo. Most likely the pinion depth is off.

Keep tring and good luck, but this is one place that you can not just slap it back together and say "good enough for goverment work" just a couple of thousands of an inch make the differance between a noising set or damage and perfection.

No your not being a dick. I know pinion depth is in spec because I used a pinion depth gauge. Also pinion gears come with a pinion depth stamped or scribed on the head of the gear. But I know that pattern is always the best measure of pinion depth. I was just saying that the pinion depth in terms of measuring from center line of the ring gear was exactly where it should be when using a pinon depth gauge. I know backlash is in spec because you can actually measure this with a dial. Not to be rude, but have you done a rear end before? Maybe I'm not understanding your question. There are ways to check these specifications with the right tools.

Also I did apply friction when checking pattern. I put the axles back in with the drums and pulled the e brake until I had decent drag. Maybe the pattern is clear on the coast side because I apply to much ebrake? I know it was harder to turn the pinion flange checking coast side rather than drive.

My understanding from what I've researched is that you are only concerned with centering the pattern between face and flank of the tooth.

Also I am not trying to slap this together. I don't know why you would think that :shrug: This is the reason I am asking for assistance to get some input.

Thanks :beer:

 

[90FoX]

I agree with CMR. Ideally there should be no hard edges, the perimeter of the pattern should feather out in all directions.

But in the real world you are going to be hard pressed to get a textbook pattern, just a best case.

If it were me, I'd make some minor changes and see where it goes.

What minor changes to you recommend? Is the pattern to close to the flank of the tooth?

That looks good. one trick I know of is to use or try your old pinion shim first. saves some time.

Nice, I hope your right. I'll wait on some more input before I make any changes so I can get a little bit of a consensus on this, if possible.

 

[90FoX]

.

 

[Brian's SVT]

I would say if you checked the stamped pinion depth and done everything you have said you should be pretty safe it sounds like you did it all right with the dial indicator and depth gauge i was worried when i did mine the first time but it sounds like we have taken the same steps and mine worked out great.

Good luck.

 

[90FoX]

So I changed the pinion depth and took some better pictures.(at least I hope they are good enough for you to see the pattern)

I took the pattern twice, once with drag on the diff and once without drag.

What'yall think? I think it looks good :dunno

First are the pictures of the pattern with drag on the carrier:

Drive Side

Coast Side

.
.
.
.
.
.
.
.
.
.
.

Now are the pictures of the pattern without a load on the carrier:

Drive Side

Coast Side

 

[CJK440]

Looks like you added more shim (move the pinion closer)?? How much did you change it? I would have taken a couple thou out.

I'm no expert but have been able to set up about a dozen rears over the years with good results. I usually set it up a few different ways to push the pattern in both directions off of perfect then zero down to the best case. It's a PITA but rewarding and easy on the wallet. I dug back and found a pretty good pattern to show you.

Notice how the contact patch has a general oval shape with the outside fading instead of a sharp paint line?

If you are working on a previously untouched factory setup, how far are you off from the shim that came in it?

 

[90FoX]

Hey thanks CJ,

Your pattern looks fricken sweet! Did you apply load when getting the pattern? I wonder why I don't have as oval of a shape on the drive side.

I did add shim. The reason my pattern looks different is because I applied load in the pattern pictured in the first post of this thread and the first set of pictures in my last post.

I think the load makes the pattern have those sharp corners. If you look at the second set of pictures in my last post the edges are more diffuse, this pattern was made without load on the gear set.

It not factory when I set it up. I had these gears already. My intention was to replace my pinion seal but I noticed my carrier was damaged etc and decided a full rebuild was due.

I think its to much towards the flank of the tooth myself.

What changes would make the pattern higher towards the face?(I'm not worried about heel to toe, apparently that is difficult or impossible to change without machine work)

Thanks

 

[CJK440]

The load really just allows for a better contact "print". You really are not deflecting anything.

Based on what I see I would try a pinion shim -.002-.003 smaller than your first attempt.

But, before you change anything, clean off your compound and try again using very little of it. All you want to do is almost "stain" the gear tooth, not coat it. If the marking compound is to thick, thin it with a drop of gear oil.

 

[90FoX]

The load really just allows for a better contact "print". You really are not deflecting anything.

Based on what I see I would try a pinion shim -.002-.003 smaller than your first attempt.

But, before you change anything, clean off your compound and try again using very little of it. All you want to do is almost "stain" the gear tooth, not coat it. If the marking compound is to thick, thin it with a drop of gear oil.

I'll do that. The compound is super thick and hard to get on in thin coats. I was thinking that a little less shim on the pinion center the pattern more.

Ill try to post pictures tonight or tomorrow.

 

[90FoX]

Hey that gear oil really works well with the marking compound. Thanks for the tip! :beer:

So I called richmond gears tech support today because something wasn't right for me.

Not sure if I mentioned this in my prior posts but because the gear set is used for over 10k miles he said the gears have been run like this for so long that it's best to keep the original shimming on the pinion gear.

Well I just put it all back the way it was before I took it apart, including original factory carrier shims. Not sure what to make of the pattern. Definitely looks better I think. I'm getting more oval/rectangle pattern on the drive side.

I removed 0.016 from the pinion shim if anyone cares. For proper pinion depth it actually needed 0.044 which apparently is way more than what is the usual shim for a 8.8. I think he said normally for a 8.8 we see shimming on the pinion in the range of 0.26-0.35.

Im lost as to why the pinion depth gives a pattern like this at 2.603 when the suggested depth is 2.619. Maybe it was originally set up incorrectly and over time deflection etc changed the gear set to a point where the correct pinion depth does not provide an acceptable pattern.

 

[CJK440]

Pattern looks much better.

Drive side looks great. Coast seems a bit high on the tooth but if you are using the shim that these gears were run with, I'd leave it.

I didn't realize these were used gears. Setup is pretty tricky and even the experts I talk to say its hit or miss. The drive side wears the most so the pattern is hard to read on used gears so lots ignore it and just check for coast and hope for the best.

Not sure how to explain the shim variation. Personally I fumbled pinion depth measurements and even had problems with bearings & races not seated all the way. Maybe the guy with the die grinder marked the depth goofed. Goes to show how installed height is great to start but in the end, its the contact pattern that is the final check.

 

[cmr98cobra]

Looks much better, sorry i didn't get to help you more... haven't been on. But to ansewer your questions about my past, Yes i have done plenty of rear end rebuild's. I've been a dealer technician for the last seven years, and worked in the scca pro racing world challange before that, so yes, I do know what I'm talking about. The only reason I asked is because alot of guys try to do their own gears only to find out that setting up a rear-end is harder than rebuilding their engines. It wasn't that I was questioning your abilities or knowledge I was just tring to figure out what you had already done. But you look like you got it pretty close, You might get a little moan on the coast but nothing to really be to worried about. Carrier shims are to control backlash and bearing preload as long as the pinion dept is set correctly and the orginal carrier is being used the shims should work. About the pinion depth, what pinion depth tool did you use a ford tool, or a universal? Second the number stamped on the head of the pinion usanally (but not always) shows weather the head was machined to the strong or weak. What this means is that the axel housing is machined to it's spec then the gears are cut to their own tolerances, when you check pinion depth that will tell you the distance to set the pinion at if and only if the ring and pinion were machined perfectly down to .000 which doesn't happen most sets are off by .003 - .015 in that case you would see a number on the head or on the side possiblely that would say -003 or i have also seen them like -3 or 3, +3, .003. If the number was negitve that would mean that you would have to add that to the pinion depth measurement, if the number is postive then you would need to take away from the overall shim. This might help explain the weird numbers that you gotten. If you've got any other questions feel free to message me. good luck, hope this helped.

 

[90FoX]

I thought I had mentioned they were used.... opps :burn:

I'm honestly frustrated that it was as easy as putting the old shims in. Oh well at least there aren't any more hurdles to jump. She's ready to run :banana:

I plan to install a new set of gears sometime in the near future. I hope setting correct pinion depth with those will proved to work. I think it didn't work here because these are used and the shop who set them up probably just slapped it together and figured the pattern was "good enough".

This is why I hate ****ing shops. No one has the incentive to do the best job...just good enough to last and get out of the shop quick enough to start the next car. :nonono:

I appreciate your time bro, thanks for the help :beer:

 

[90FoX]

Looks much better, sorry i didn't get to help you more... haven't been on. But to ansewer your questions about my past, Yes i have done plenty of rear end rebuild's. I've been a dealer technician for the last seven years, and worked in the scca pro racing world challange before that, so yes, I do know what I'm talking about. The only reason I asked is because alot of guys try to do their own gears only to find out that setting up a rear-end is harder than rebuilding their engines. It wasn't that I was questioning your abilities or knowledge I was just tring to figure out what you had already done. But you look like you got it pretty close, You might get a little moan on the coast but nothing to really be to worried about. Carrier shims are to control backlash and bearing preload as long as the pinion dept is set correctly and the orginal carrier is being used the shims should work. About the pinion depth, what pinion depth tool did you use a ford tool, or a universal? Second the number stamped on the head of the pinion usanally (but not always) shows weather the head was machined to the strong or weak. What this means is that the axel housing is machined to it's spec then the gears are cut to their own tolerances, when you check pinion depth that will tell you the distance to set the pinion at if and only if the ring and pinion were machined perfectly down to .000 which doesn't happen most sets are off by .003 - .015 in that case you would see a number on the head or on the side possiblely that would say -003 or i have also seen them like -3 or 3, +3, .003. If the number was negitve that would mean that you would have to add that to the pinion depth measurement, if the number is postive then you would need to take away from the overall shim. This might help explain the weird numbers that you gotten. If you've got any other questions feel free to message me. good luck, hope this helped.

No problem, I appreciate any help. I know people can't drop what their doing to help me haha.

I see what your saying. The internet is weird sometimes, in that a simple comment can be interpreted many different ways. Obviously you have waaaaay more experience than me :read:

I used a "Proform Pinion Depth Setting Tool". It is a universal tool. The ford tool is super expensive. But I figure as long as the tool is square on the carrier bearing cap surface, readings should be accurate.

I've heard t&d machine (i think that's the name) has a tool like fords, which rides in the carrier bearing bores but its diff than fords tool because this tool has a dial indicator in the center of it.

These are richmond gears so the instructions state the number is the pinion depth. From my research I thought it was only ford gears with had +/- dimensions.

I hope to set up a new gear set in the future and I it works out well. I really was looking forward to setting the gears to spec and checking pattern, but used sets are muuuuch diff than new, something I didn't know. Maybe someone can learn from this thread in the future. :beer:

 

[CJK440]

I used a "Proform Pinion Depth Setting Tool". It is a universal tool. The ford tool is super expensive. But I figure as long as the tool is square on the carrier bearing cap surface, readings should be accurate.

You can't really assume the cap parting lines are in the middle of the carrier bearing bores. That may have been your issue all along.

I use a depth mic to check the pinion depth off of the parting lines, but I will check the depth of half the housing bores and compare it to the depth of the cap bore and figure out where center really is. Its more math but it works. In some cases its pretty far off. Checking against a fixture that fits in the bearing bores is the most direct way.

Also, I personally, and have heard of quite a few others, that had some trouble getting great patterns with Richmond gears. Good gears but tricky for the shadetree.

 

[90FoX]

You can't really assume the cap parting lines are in the middle of the carrier bearing bores. That may have been your issue all along.

I use a depth mic to check the pinion depth off of the parting lines, but I will check the depth of half the housing bores and compare it to the depth of the cap bore and figure out where center really is. Its more math but it works. In some cases its pretty far off. Checking against a fixture that fits in the bearing bores is the most direct way.

Also, I personally, and have heard of quite a few others, that had some trouble getting great patterns with Richmond gears. Good gears but tricky for the shadetree.

Its not the center line, that's why I calculated a offset which was subtracted from my pinion depth measurement.

heres the instructions, you can see how the offset is calculated :thumbsup:

http://www.proformparts.com/PDF/pinionsettingtool.pdf