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Discussion Starter #1 (Edited)
Hi all,
I'm attempting to set up my first Ford 9" and am having some frustrations getting my gear pattern correct.

Here's where I'm at:
The 3rd member housing and pinion support are both new aftermarket nodular iron replacements from Dutchman Axles.
The pinion preload has been set to 17 in/lbs with a crush sleeve eliminator kit.
I'm installing a Detroit Eaton TrueTrac differential/carrier
I'm using brand new Motive Gears 4.11 gears.
I have checked the run-out on the ring gear and it's around 0.001"

I have tried to follow guides online about how to set gears but they either:

A: Contradict each other
B: Don't look anything like the patterns I'm getting
C: If they kinda/sorta do look like the patterns I'm getting, the corrections they suggest don't seem to fix it.


I know what a good pattern is supposed to look like, but I can't seem to accomplish it with the gears that are sitting in front of me. So, I started at my deepest shim. For those who've worked on an 8.8", on a Ford 9", decreasing shim size moves the pinion closer to the ring gear / deeper.

So, I started at a deep setting and moved back out. At each pinion depth setting, I set the backlash using a depth gauge to about 0.007" - 0.009", which is the spec given by Motive Gears.

Here's what I got:

0.018"





0.020"





0.023"





0.025"





0.028"





(10 pic limit)
 

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Discussion Starter #2 (Edited)
0.031"





0.033"






It seems the better I get the depth (with a broader pattern between the root and crown), the further the pattern moves to the heel and toe. From what I've read online, if both move to the heel or both move to the toe, that can be fixed with the backlash. But if one moves to the heel and the other to the toe, then that's a pinion depth change. But changing the pinion depth seems to make the pattern worse.

Any thoughts?
What depth looks the best?
Directions to go from here?

Thanks all.
 

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Man of endless projects
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i mean it looks like your on the right track. definitly seems to look better more you shim it. my Differential book says use .007-.010 backlash for aftermarket gears also (.010-.016 for OEM). have you tried tightening the backlash abit tighter to spec to see what it would look like?

on my friends 8.8" i did few weeks ago we used Ford Racing gears which call for tighter backlash than most my service manaul and my differential book called for. using OE Fords recommended backlash (8-15 but 12-15 perfered) was too loose and gave a crappy pattern with contact on both ends like yours. but using Ford Racings tighter backlash (8-12) gave a much better pattern and more near the center. might try it tighter and see what it does and note the backlash if you get it correct. then contact Motive Gear with your findings if its much tighter than spec. might even be a defective set. with it abit on the tight side you might find it doesnt need pinion shimmed as much also

in my book having pattern heel and tow like that does show it as an acceptibale pattern as long as its doesnt look too deep or shallow. it goes on saying that sometimes thats due to the actual machining of mthe case being abit off and nothing you can do about it

159011


by 'depth gauge', what are you using to measure backlash? a dial indicator im assuming? or something else? depending on anlge and position ofthe tool, it can defiantly read different results so make sure you have it setup to read as accurate as possible. a couple thousands of an inch of backlash can make a pretty big change from what we saw on this 8.8"

i didnt take pics of the end pattern but this is what it looked liek with the correct pinion depth and but 0.004 too loose of backlash. the final pattern looked very good compared to this

159014
159015
 

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1996 EB w/5.8 TOO much lift, 44" Mudders & 5:43-5:38's
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I agree with above and posted this in his other thread:

#237 20 h ago
Your pattern, to me anyways, appears to be close in 0.023-0.025 and I think increasing the backlash should center it more towards the heel, as decreasing it should move it closer to the toe.”

I was always taught that you need at least 3/8” off of the toe on your pattern
 

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Discussion Starter #5
Thanks for the response.

Here's Motive Gear's install guide:


They state that the backlash should be between 0.007" and 0.009", which is about what I shot for in all of the above pictures.
And yes, I'm using a depth gauge. This is a pic of the front, but same idea. Doing my best to get a solid 90° angle on the teeth to get a good reading:



I also did some testing by going from extremely tight to extremely loose backlash. I found that when the backlash got below 0.007", the drive side would stay stationary, but the coast side would move toward the toe. If it got above 0.009", the coast side would stay stationary while the drive side would move out toward the heel. (Or maybe it was the other way around, it was yesterday). Either way, that helped confirm that 0.007 - 0.009 was where the backlash should be, as it got both coast and drive sides as close to each other as possible.


@Kingfish999 in your experience, which pinion depth looks like it's on the right track? Trying to get a consensus.
I agree that the 0.023 - 0.025" range is the best as far as centered on the tooth, but it also looks root heavy and very triangular, which I don't like. I just can't seem to get the broad, centered "good" pattern that almost every site shows, no matter what I seem to do, so I'm a little flustered.

The 0.031" to 0.033" range start to get that more "rounded" look, but also put the pattern up on the crown when you get to to around 0.033", and I've read you want space between the pattern and the crown.

Guidance?
 

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Man of endless projects
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in those links for the pics, can you change it so it says 'Original' instead of 'Fullsize?' for example, that last pic link is
ww.supermotors.net/getfile/1159304/fullsize/20200506-20.12.33.jpg

if you change it to original it will let us view the picture MUCH bigger where we can see it better
ww.supermotors.net/getfile/1159304/original/20200506-20.12.33.jpg

turns this


into this. which can be viewd much bigger. and if on a computer i can view as like 8x bigger
 

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Discussion Starter #7
One sec. I might have to go back and replace all the pics. This new forum doesn't appear to let you reedit the image tag (you only see the actual picture in EDIT mode).
 

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Discussion Starter #8
Done. Thanks for the tip, I didn't know about that one (and will use it in the future for sure.)
 

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ya thats the issue with Supermotors. they downscale thier pics to a certian size even if the original pic was many times bigger. thats why you have to click ok the pics to view there original size

EDIT: ya know im not really sure what to think. i was thinknig that the sharp line on the bottom on the coast side is still there even on the .033 shim and that usually indicates you need more shim for most patterns. i would almost think still need more shim and then with backlash and see what you get.




according to Randy:
The only part of the pattern that helps me set pinion depth correctly is the contact position
between the face and flank. If the pattern appears to be toward the heel or toe, I pay little or
no attention. While making adjustments, the pattern may also change toward the heel or toe,
but in most cases this aspect of the pattern cannot be put into an ideal position. Even if it doesn't
seem intuitive or reasonable, I am only concerned with the pattern position between the
face and flank. I have found that housing alignment and the exact position of the pinion bore
during manufacture affects the heel to toe pattern and cannot be altered without machine
work. Bottom line: a contact pattern that is centered from face to flank always indicates a correct
pinion depth, even if a centered heel-to-toe pattern cannot be obtained.
 

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Discussion Starter #10
Hrmm... Well, I have more shims. I can see what 0.035" and 0.038" look like. Can't hurt anything. I'll do so and post up pics.
And yeah, I think that's where I've been getting frustrated.
Online guides say they NEED to be in the middle. There's only one ideal pattern, but never really state what happens if you can't get it.

Then (as I was complaining about in another thread) videos online have them get one wrong pattern, make a few adjustments, and suddenly beautiful. That doesn't help me! :p

The Yukon Gears image with "Acceptable Patterns" not being centered on the tooth is the closest I've found to following what I'm seeing with my gears.

I'll post up pics when I get more patterns.

Thanks
 

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Discussion Starter #11
Good morning all,
Okay, so last night, I shimmed it to 0.035" to see where the pattern went, and I can tell it's definitely too shallow. The pattern started to get out onto the corner of the teeth:





I backed it down to 0.031" again to test it and play around with the backlash. I still don't like how it's out toward the edges, but the pattern is a bit more broad. Then again, I don't have a trained eye for this, so maybe I'm way off.

@ 0.007" backlash





@ 0.009" backlash





The 0.009" of backlash looks like it's starting to put the pattern out onto the tip of the tooth, which doesn't seem good.


Thoughts?
 

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im liking that .009 backlash alot better. it doesnt have as sharp edge and that might be the key for that gearset. i would use that if you cant get the pattern any better. so from here tho you might try next step thinner of a shim with that backlash. that might get the pattern more more centered height and width wise. hopefully your not running out of paint. that particular gearset might perfer more backlash than most. but as you see .002" of backlash makes a pretty big change
 

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1996 EB w/5.8 TOO much lift, 44" Mudders & 5:43-5:38's
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I agree with Kingfish that you need to shim the pinion less, but I think that the 0.007 backlash is keeping the gear from running off the heel. Curious to see what the pattern & backlash will be with less pinion shim.
Starting to wonder if it's just the gears at this point.

Just my $0.02
 

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Discussion Starter #14
Less shims than the 0.031"?
Thinking 0.028"?

Do you think there is something wrong with this gear set? Every single part I'm using is brand new, as far as the housing, pinion support, bearings, shims, gears, and true trac, so nothing should be worn. If there's something faulty, I'd like to address it. But if it's okay, then I'll go with it. But... I don't know from my experience.
 

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id try the .028" with the extra backlash and see. if it comes out worse than i would probably stick with the .031 w/ .009 backlash. but i feel the .028 w/ .009 might make it better

Motive Gear is suppose to be a decent company. i myself never used them tho. a few weeks ago at a friends shop they had Motive Gear on a 9" and was having all sorts of issues getting a pattern and went from zero shim to .030 shim and all combinations of backlash. last i heard they were going to have them warrantied as defective. could be defective batch? i generally use Dana SVL or USA Standard, never really had much of an issue with either.
 

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in those links for the pics, can you change it so it says 'Original' instead of 'Fullsize?' for example, that last pic link is
ww.supermotors.net/getfile/1159304/fullsize/20200506-20.12.33.jpg

if you change it to original it will let us view the picture MUCH bigger where we can see it better
ww.supermotors.net/getfile/1159304/original/20200506-20.12.33.jpg

turns this


into this. which can be viewd much bigger. and if on a computer i can view as like 8x bigger
You may be measuring the backlash incorrectly, I believe it should be measured with the gauge stem tangent to the ring gear, you seem to be measuring it at less than tangent, which may be giving you an incorrect lash reading. (and thus the difficulty in getting the pattern)

Take a look at how this guy measures backlash, notice that the stem of the dial indicator is tangent to the ring gear.
 

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1996 EB w/5.8 TOO much lift, 44" Mudders & 5:43-5:38's
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Good pick up @Mikey350 , didn't even notice he wasn't parallel with the ring gear without my glasses
 

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Discussion Starter #18
That may have just been off kilter for that one picture, but I've had my gauge as close as possible to about a 90° from the tooth.



I did some more playing around today. To put my frustrations aside, I dove in and worked on the Dana 44. I think I had it close to set up in about 3 adjustments. At least I was able to give myself some reassurance that I kinda have an inkling of what I'm doing.

So back to the 9".

I decided to run the backlash way out and just see what it did as I moved it in. I went with 0.031" since it seems like it's a decent depth.

I started at 0.019" of backlash. Personally, I thought the coast side looked just about perfect (if not a little toward the toe).





Next is 0.015"





Then 0.009"





Finally 0.006"

I thought the drive side is looking pretty decent here.
If I could get the 0.019" coast matched with the 0.006" drive, I'd probably call it good.




I'm open to suggestions. Otherwise, I'll contact Motive Gear.

I bought the set from Dutchman Axles' "garage sale" section for $100. As such, they're as-is and have no warranty through them. The box has a date stamp of April 2016.
 

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i still think your putting way to much on having the pattern being too much at toe/heel. to me it looks like the .019 backlash has the best contact pattern not having any sharp edges. but that much backlash means something is wrong. thats why i think a thinner shim and less backlash might be the trick. but im also suspecting defective set.

i would jsut contact Motive and see what they say.
 

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Discussion Starter #20 (Edited)
i still think your putting way to much on having the pattern being too much at toe/heel.
Yeah, still learning here. I just know all the reading I did before I started always showed a good contact pattern to be centered. That "acceptable patterns" image from Yukon Gears you posted above where they're off toward the heel/toe is the exception, not the norm. At least in regards to how-to guides and walk throughs. Then again, they are pretty top notch stuff, so I would hold what they say in high regard.

to me it looks like the .019 backlash has the best contact pattern not having any sharp edges. but that much backlash means something is wrong. thats why i think a thinner shim and less backlash might be the trick. but im also suspecting defective set.
That was my thought too. 0.019 looked good, but that's just a lot of backlash. It wasn't just on the depth gauge, but it also just felt like too much when I clicked the gears back and forth.

Also, double checking, simply due to the difference between the 8.8" and 9", when you say "thinner shim", do you mean putting the pinion in deeper? I ran into that a bunch online when "thinner shim" meant "thicker shim" with the 9", which got confusing. Pinion toward or away from the ring gear leaves little doubt. :D

i would jsut contact Motive and see what they say.
Yeah, I think I'm going to. Hopefully they'll do something. Since the production date is 2016, they're already 4 years old and their warranty is only for 2 years. Not sure how that factors in when they were 4 years old when purchased. Probably should have just bought them direct, but $100 for a brand new set was tough to pass up.
 
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