Steven6095

Hello Currently havea set of screaming 4209-M373s (came in a motive box) in my car now.
Yes I know that some people can have a miracle and get those installed without noise, but thats just not happening with these.

Today I got in the following:
See pics below.
These are in a Ford Racing box and are part # M-4209-L373, but the date on the box is confusing me.
Yes I know these are made by motive too, but all 3.73s sold by Ford are made by Motive now. The Ls are supposed to have the new manufacturing process and are supposed to be much easier to install. I do not know what the difference between the two looks like. Hopeing someone here would. Thanks

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MusiccityGT

The new process uses a single pass cnc cut instead of the old 3 pass method as I recall. They also makea backcut on the pinion to reduce noise. Can't really tell from the picture if the backcut is there. I have not heard that Motive had started doing the new cnc process, but could be.

mustangman02232

those look straight cut, if they are they WILL install, helical cut gears i.e motives, will NOT whine if you have an installer smarter then a monkey

Steven6095

Better pic

DJACKSO

What you are looking at there is called end relief. It prevents the gear tooth form accepting loading (stress) at the ends. They grind clearance so that it does not make contact as it roles.

MusiccityGT

From Frpp-

M-4209-F373N*-Replaces our popular M-4209-F373. New manufacturing technology utilizing a Face Hob Process which features a single pass pinion tooth machining operation compared to a conventional three pass process for machining. CNC cut and lapped gear teeth. Higher strength and better quality gears are produced with the Face Hob Process. NOTE: These new gears look a little different, the gear teeth are cut on a different angle and the ring gear has a bevel on the back of the gear.

Steven6095

Those are actually 8 inches, but I get what you are pointing out.
I looked at the website again for the millionth time and I see where the L373s do not use the new process. I feel like a complete idiot, but then again what revision of the Ford Racing 7.5 3.73s are people buying to replace the old version? A bunch of people on the forums are saying to get the new revisions. I would have sworn though, that these Ls are a newer part.
Ford Racing’s current catalog even lists these L373’s as a NEW part. What did they replace?
The current ford Racing catalog shows the new part as # M-4209-L373-M
These are labeled M-4209-L373
I wonder if these are actually different.
Date code is June 13,01 right?

The ones I have in the car now, which I thought were M373s came in a motive box with motive instructions and a Ford Racing sticker on the box with no accessories.
These are in a Ford Racing box with accessories. I also do not believe the older ones had anything written on them. These do.
I have done so much reading on the forums and I thought I had this all figured out : (

Steven6095

Just downloaded the 07 catalog and they do not have the new by them, but the late 06 catalog does.

Haulupki

the writting on the pinion is from the inspection process and will aid the installer. For instance if the nominal gage length of the pinion gear is 2.312 then your gear at 2.317measures .005 oversized on the inspection gage.
The installer will look at what your current "old" pinion gear has written on it. If it has the same measurement then he will not add or remove any shims to "start" for the install. The same amouut of shim will go back in with the new gears and bearings.If the old gear has a smaller number like 2.315 then .002 shim should be added to compensate for the differnence between the old and new gear, or if it is a larger number like 2.320 then .003 of shim should be removed. Then goes in the carrier with its new ring gear and then blueing process starts to see if you need to make further shim adjustments to either the ring gearand/or the pinion gear.

Steven6095

Thanks for the info : ) !!!!

My main concern now is that these may be the same da*m ones that are in there now.