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Are the ring and pinion marked with any kind of "lot" number? Back a million years ago, Ford 9" gear sets had numbers stamped on each gear, as the gears were a "matched set". I think the gears were lapped together when they were ground. (I'm wondering if those gears will never have a good pattern, if they were not matched when they were ground.)
Good Luck
 

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Discussion Starter #22
Yes, both the ring and pinion have a "6205" scratched onto the surface with an engraving tool.





There are also these other markings that I don't know what they mean.





Otherwise, there's the part numbers:



9X37 _ [MG] _ F890411 _ 2494

37/9 = 4.11
Motive Gear
Gear Set Part Number
(I'm guessing the part number for the ring gear)



[MG] _ 9X37 _ 2495

Mogive Gear
37/9 = 4.11
(I'm guessing the part number for the pinion)
 

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Discussion Starter #23
Today I ran through all the backlashes for 0.028" shims (setting the pinion a little deeper):

0.017" backlash





0.014" backlash





0.011" backlash





0.009" backlash





0.007" backlash



 

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Discussion Starter #24
Out of curiosity, I also did 0.035" but it was just so obviously wrong I didn't even take pictures.

Here's also a few for 0.025"

0.013" backlash





0.008" backlash



 

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what was the part number? apparently if it ends with an A, its made in china and also cost less. those only cost like ~130$ while the others are like 200ish

yess im aware of how the 9" shims the pinion. its kinda the opposite of the usual and they do word it confusingly. i made that mystake at first when my friend asked me about his 9" issues and then i remembered about that.
 

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Discussion Starter #26
what was the part number? apparently if it ends with an A, its made in china and also cost less. those only cost like ~130$ while the others are like 200ish
The part # is F890411
On Summit, they're about $215. They're from their Performance series.

yess im aware of how the 9" shims the pinion. its kinda the opposite of the usual and they do word it confusingly. i made that mystake at first when my friend asked me about his 9" issues and then i remembered about that.
Cool, just checking. I know that was driving me crazy when I was looking at how-tos on line. Most of them were opposite of what I was doing, and then some of them were correct because they were working on a 9", so it made it hard to track.
 

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Discussion Starter #27
So, I spoke with Motive Gears today, and they had me email a couple pics of patterns I've taken. Went back and forth a bit and their tech said to try 0.020" @ 0.008" backlash.

This is what I came up with:





He said that that looked good and he would run with it. He said sometimes you'll get a little root heavy line, but the majority of the pattern is in the center of the tooth. :unsure:
I'm an amateur and they're the professionals who designed it, so I'm inclined to believe them.
 

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Discussion Starter #28
Also, while I have your attention, what do you think of this pattern for the front Dana 44? It looks good to me, but figured I'd get a second opinion.



 

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1987 Bronco, 300 EFI, 3.08 gear, NP435, 32" tires, 2" level kit, dual exhaust, manual transfer & hub
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I've been following without comment so far, since I've had nothing to add being completely inexperienced in this regard. Been educational though, and I hope to regear some gearboxes soon so thanks for sharing the process! I've learned to take what I read with a grain of salt when it comes to automotive stuff, since reality often has variances that can't be summed up with one size fits all solutions. I am intrigued by Motives response. I would love to hear your feedback down the road on how the 9" goes once it's all put back together and driving. Like you, I was interested in solving why you had such a harsh line when it was centered best. If Motive thinks it's good, I'd go with it too. But, being a perfectionist, I'd always have it in the back of my mind. Listening for abnormal noise, checking the oil for signs of excessive wear... Once again, thanks for sharing your process, frustrations and all! I feel confident I can tackle this when the time comes, and I'll probably be referencing your post and some of the links other members have provided along the way. Super helpful! Good work!
 

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Discussion Starter #30
Hey @Fort Ford , thanks!
Yeah, it's been a great project, and overall I've really enjoyed it and learning how it works.
Getting a proper pattern has been about the only frustrating part. Otherwise, it's actually quite straight forward (a lot more so than I thought).

And I'm like you, I want it to be perfect. Especially since this is my daily driver. But yeah, he seemed totally confident on it.
I'll be paying close attention to it and will report back.

Your 87 sounds like it is just about like how my '81 was set up. 300 I6, NP-435, 32" tires, and 3.00 gears (9" vs 8.8"). Awesome combo! Overall, it was a really nice setup, and a good balance between performance and economy. That said, I had a similarly set up 84, but about the only difference was 3.55 gears (8.8") and that was so zippy it almost drove like a sports car. It was fun. But, without overdrive, getting close to 3k on the interstate wasn't my favorite.
 

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1987 Bronco, 300 EFI, 3.08 gear, NP435, 32" tires, 2" level kit, dual exhaust, manual transfer & hub
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Your 87 sounds like it is just about like how my '81 was set up. 300 I6, NP-435, 32" tires, and 3.00 gears (9" vs 8.8"). Awesome combo! Overall, it was a really nice setup, and a good balance between performance and economy. That said, I had a similarly set up 84, but about the only difference was 3.55 gears (8.8") and that was so zippy it almost drove like a sports car. It was fun. But, without overdrive, getting close to 3k on the interstate wasn't my favorite.
Don't want to hijack your thread, but thanks for the comment. I actually have a full 3.55 setup sitting in my to-do list that I want to swap in to see how I like it. I do really enjoy how it cruises along at highway speed around 2k.... but I would like to see how it zips with a little more oompf in the gears. If I was made of money I'd go overdrive with 4.10's and have the best of both, but reality is compromises :)

And since nobody has chimed in on your d44, based on Motive's thoughts on the 9", it seems like you've got it fairly well centered to me!!
 

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Any chance the "BL 0.008/10" engraved on the gear means Back Lash 0.008/0.010? Just my guess.
 

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Discussion Starter #33
Hrm... it really looks like it!

But it'd be odd for each gearset to be given a different backlash range, and then have a printed range in the manual.

Dunno! I'm curious.
 

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Hrm... it really looks like it!

But it'd be odd for each gearset to be given a different backlash range, and then have a printed range in the manual.

Dunno! I'm curious.
The guy that ground and lapped the gears was NOT the guy that wrote the manual.
 
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