Motive Power Ring and Pinion Set

[8EL]

Received a new ring and pinion gear set from Tam's Model A Parts yesterday. This set is made in Italy and marketed by Motive Gear. The instructions sate to verify that the serial numbers on the ring and pinion match, as they are lapped to a final fit, and are not interchangeable as individual units. Also stated in the instructions is that the number on the pinion is the reference to to dimension from the axle center line and the face of the pinion. It goes on to say that this tolerance is to be held to not greater that +- .002".

Makes sense right?

The only numbers can be found that could be realized as unique to these two parts are hand written in electric pencil, and are unlegible. Secondly, there would have to be some sort of special fixture, not sure how it would work to be able to precisely measure from the axle center line to the pinion face on this type of unit. Reason being that the axle bearings that the measuring tool would need to reference are located in the bolt on axle housings. Once bolted on, there is no means to access any type of measuring device to make this reading. On salisbury and carrier type rear ends ample access is to be gotten through the removed rear cover plate or removed carrier.

So I called the Motive Power technical support help line given wit these instructions for clarification. After much too do, I was given a long rambling statement from the supplier of this part that they have no information on it and could be of no further assistance.

I will be calling their customer support department Monday to get to the bottom of this matter as this answer can not be considered acceptable.

What do you guys make of the situation? Anyone installed one of these gear sets?

[nkaminar]

I am not the premiere expert here but I have set up ring and pinion gears. I set them up using India bluing and noting the pattern on the gears. It involved assembly, disassembly, repeat until I got it right. The pattern should be in the center of the gears and not to one side or to the top or bottom. Measuring from the centerline to the face of the gear will involve a sophisticated measuring system that is generally not available to the amateur.

[8EL]

Also 4 of the ring teeth have residual yellow gear marking compound to be seen. It is certain that this ring has never been put in service, but is this evidence of rejection by some other mechanic, or is it just the standard manufacturing operating process check? I lean toward the latter. One other thing concerns me is that it appears the date stamped into to ring is 8/21, whereas the date on the box indicates 1/26/22. Perhaps the part sat on the shelf for 5 months before being boxed? or do I have a mixed and matched Frankenstein?

The part number is B4209HS - HS I take to indicate "high speed" as it is a reduced under stock reduction of 3.54:1 ratio (39 ring - 11 pinion).

Looks like Tam's sourced it from Ford V8 sales Inc.

[8EL]

I have the tools to measure from center line to pinion face, but there is no way to access on this style unit. When axle housings are bolted on, there is no conventional means that I can see to access these components....

[alexiskai]

What size in inches are Model A ring gears?

[bobbader]

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First of all, stop getting crazy about the fact that setting these up is not done the same way you are used to for other applications. You can drive yourself nuts constantly trying to fit the proverbial square peg into a round hole. Second, remember Henry’s big thing was assembly line efficiency. These units were not subject to time consuming adjustment on the assembly line. They were meant to go together as quickly as possible going down the line. If it was any different, adjusting procedures would be evident. They basically go together with the intent that, if the gears are matched, bearings are new, and correct assembly features are followed, these units will perform within the means intended. Can these means be perfected using specific tools? Yes. Do a good study of Tom Endy’s rear end rebuild at Santa Anita A’s website.I believe you’ll find enough info there to soothe your need for knowing you’ve set the wheels in motion properly. Good luck.

[jimvette59]

They are both marked 1 7.

[Flathead]

One important thing to note is that these are "spiral bevel gears" and are not as fussy as "hypoid gears" Post #6 has it right. Those may be general directions and refer to hypoid style gear set-up.

[Gene F]

Well since never installed tell Tam's to send you a return shipping label. If they refuse document who you talked to, tec., and call your credit card company and have them back-charged. This just sell em' something attitude really rubs me wrong.

[J Franklin]

Originally Posted by Gene F

Well since never installed tell Tam's to send you a return shipping label. If they refuse document who you talked to, tec., and call your credit card company and have them back-charged. This just sell em' something attitude really rubs me wrong.

What are you saying Tam's did incorrectly? Why should they bear any cost for return when what was sold was what was purchased?

[bobbader]

First of all, Tam’s is a very, Very reputable dealer and, it doesn’t sound like they’ve even been part of this conversation yet. Let’s calm down a little and help 8EL work through this.

Second, the date on the box compared to the engraved date on the part has little significance. It could be the date the manufacturer sold it to the supplier Tam’s bought it from. It could be the date the supplier sold it to Tam’s. It could be the date Tam’s put it in their inventory.

It’s not strange for the gears to come with the yellow marks from the factory. This has something to do with their system of checks and could be as simple as a way they identify totally finished product.

Finally, 8EL, take a deep breath. Read Tom Endy’s article, if you still have questions, correspond with Tom here on Fordbarn by Private Message or email. He’s a fount of information. Or ……….. call Tam’s and engage them in conversation. I think that would help put your mind at ease.

It sounds like you have experience with rearends in general. Yes, this one is different but, if you let it, your experience will bring you through this once you have the right info about installation. Once again, good luck.

[Synchro909]

Originally Posted by 8EL

Received a new ring and pinion gear set from Tam's Model A Parts yesterday. This set is made in Italy and marketed by Motive Gear. The instructions sate to verify that the serial numbers on the ring and pinion match, as they are lapped to a final fit, and are not interchangeable as individual units. Also stated in the instructions is that the number on the pinion is the reference to to dimension from the axle center line and the face of the pinion. It goes on to say that this tolerance is to be held to not greater that +- .002".

Makes sense right?

The only numbers can be found that could be realized as unique to these two parts are hand written in electric pencil, and are unlegible. Secondly, there would have to be some sort of special fixture, not sure how it would work to be able to precisely measure from the axle center line to the pinion face on this type of unit. Reason being that the axle bearings that the measuring tool would need to reference are located in the bolt on axle housings. Once bolted on, there is no means to access any type of measuring device to make this reading. On salisbury and carrier type rear ends ample access is to be gotten through the removed rear cover plate or removed carrier.

So I called the Motive Power technical support help line given wit these instructions for clarification. After much too do, I was given a long rambling statement from the supplier of this part that they have no information on it and could be of no further assistance.

I will be calling their customer support department Monday to get to the bottom of this matter as this answer can not be considered acceptable.

What do you guys make of the situation? Anyone installed one of these gear sets?

It's pretty clear to me that those ILlegible numbers are both 17. I would conclude you have a matched set.

[8EL]

Comforting to know that you guys see the same numbers on both parts. This is what I was trying to establish. I am not accusing Tam's of any wrong doing whatsoever. I was put off however of the response I got from Motive Power in that they had not information on their records concerning this gear set.

[updraught]

I think it is Egyption or ancient Greek.
Could be from when Leonardo invented the differential.

[petew]

I have installed three sets of motive model A gears . Just get the backlash right with the gaskets and they will be fine .
As a bevel gear they not as specific with their needs as a hypoid gear is.
Don't overthink it just put them in .

Use Tom Endy's tutorial and it will be an easy job.

[rotorwrench]

On a conventional modern rear axle a person has a lot of ways to shim so the pinion depth will coincide with the ring gear centering. While a person can make shims to "adjust" for inconsistencies in the model A banjo type differential, they will not be needed on a properly made set for these type rear axle assemblies. The first check after installing the differential bearings will tell a person whether any shimming of those bearings will be necessary.

Tom Endy's articles are on the Santa Anita As site. The Italian gears only fault seems to be that they don't provide a slip fit for the forward bearing cone on the stub shaft of the pinion. This allows for easy adjustment of the pinion preload. There are several recent rear axle threads on here to look at and follow links to other information.

I use the mustard yellow GM 1052351 gear marking compound to check the gear patterns.