3.73 gears for Shelby

Okay so I am new to this chat and am wanting to get my dad some 3.73 gears in his Shelby for him for Christmas. I was going to buy the same kit I did for my car but I am reading online and people say I need a different bearing for the Shelby. I can use the same 2010-2014 mustang gear set but where would I find a new bearing and how do I know if it would match up? Any thoughts? Thanks.


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Ford 2013-2014 Shelby GT500 Pinion Bearing

That's the 13-14 GT500 specific pinion bearing, basically same as on F150 trucks.

Most will tell u do 4:10 but I did 3:73 on mine after my BS fiasco with doing a 3:90.

Ford part # for that brg is 6L2Z-4625-AB

Tony

Not sure what year Shelby your dad has. The ‘11 and ‘12 model year with performance package have 3.73 gears in them. Not sure about other years.


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If he's posting here then hopefully his dad has a 13-14 car, otherwise it's a regular pinion brg like all the other year cars.

Cman01 said:

If he's posting here then hopefully his dad has a 13-14 car, otherwise it's a regular pinion brg like all the other year cars.

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I missed the forum category. Good point.


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Cman01 said:

If he's posting here then hopefully his dad has a 13-14 car, otherwise it's a regular pinion brg like all the other year cars.

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Yeah it’s a 13’ thanks for the input guys! Appreciate it.


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Van at Revan can set you up with everything you need including the special bearing

I got my 2013 bearing from a Ford dealership in 2016. Just call ahead to check stock but they should be available. .

Correct on bearing only difference from standard 8.8s.
And does he run drag radials?
The 4.10 and 305/35/20 NT555R combo is the best street package.
Don’t say 4.10s are too much. Not even close. 80mph at 2000rpm.
-J

I believe the pinion bearing is the TIMKEN M802048 ...

Just rebuilt my diff after the pinion seal (or something) was leaking. Found the previous diff guy had literally shafted me by using the one in the kit as opposed to the one that the car was designed with

Did loads of research to track which bearing it takes. Not only is it the one that goes in the F150, it also goes in the Lamborghini Countach


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U should read up on the 3.73 gear. Imo that gear has a tendency to whine. Only reason I'm not changing my gear is all the posts about gear whine with 373. Not as many with 4.10.

Foxbody-92 said:

Yeah it’s a 13’ thanks for the input guys! Appreciate it.


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The 13-14 is prone to gear whine and difficult to set up properly. You may want to research this more. I would make sure your Dad understand the risks/rewards for this mod before blindly doing it.

Tom

Didn't all GT500's get a different pinion bearing from the regular production Mustang 8.8's (including the Mustang GT)? I believe the 2008/09 Bullitt Mustang also got that "hi load" or "high torque" pinion bearing? The replacement FRPP 8.8 axle assembly was listed as having the unique pinion bearing, as installed in the production GT500 and Bullitt.

The 2013/14 may have gotten a different pinion bearing also, but I believe all 2007-2012's were different from the regular 8.8. If I remember correctly, the bearing is either larger diameter or thicker or both, in comparison to the regular 2005-2014 MGT...……….and I am pretty sure "High Load" was the descriptive for it from Ford.

****EDIT**** I did some additional searching and it looks like 2007-2009 GT500 did get a High Torque pinion bearing that was different from the regular 8.8, and then in 2010 it changed for 2010-2012 and then specific 2013/14 axle codes got a bearing that was different from 2010-2012.

R

I had 3.73s in my 07 and LOVED it.

That said, i believe the 13/14 cars have different trans ratios that would benefit from more gear.

13/14, use the 4.10 and let er eat!

gimmie11s said:

I had 3.73s in my 07 and LOVED it.

That said, i believe the 13/14 cars have different trans ratios that would benefit from more gear.

13/14, use the 4.10 and let er eat!

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Yes, the GT500 transmission ratios are listed in the link below for 2007, 2011 and 2013, (scroll down)…..

Tremec TR-6060 transmission - Wikipedia

The closer the first gear is to "1 to 1", the less rpm drop between shifts (Close Ratio), the further away the first gear is from "1 to 1" the more rpm drops between shifts (Wide Ratio)..... <<all generally speaking. The closer the first gear is to "1 to 1" the less initial "spin-up" of the engine at the bottom in first gear, a high numerical gear (called a low gear) helps that spin-up process along when the transmission is a closer ratio transmission.

R

My diff guy said that the whine can be dialed in and out with the pinion angle. I have on car adjustable lower control arms so will be testing this out.

To be honest, the whine isn’t bad and so much more preferable to having the 3.31 - a relatively undrivable final because it’s way too long


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BAS said:

My diff guy said that the whine can be dialed in and out with the pinion angle. I have on car adjustable lower control arms so will be testing this out.

To be honest, the whine isn’t bad and so much more preferable to having the 3.31 - a relatively undrivable final because it’s way too long


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Yes, a 3.31 gear is more of a "highway" gear, good for lower rpms on the highway and better fuel economy........and pulling top speed runs.

The 2007-2009's were the same way rpm wise, but with a wider first gear.

I would think that the add of a 3.73 gear set to a closer ratio 2013/14 transmission would be a win-win for performance, the 3.73 gear would allow the engine to wind up quicker and the lesser rpm drop between gears (closer ratio) would keep the engine in the "sweet spot", rpm wise. <<That is what the drag pack cars from the old days were all about, get the rpms up into the sweet spot quicker and keep them there through the gear changes.

The wider ratio transmissions would get the engine rpms up in first gear, but the rpm drops between gear shifts could fall out of the power sweet spots and adding a higher numerical (low gear) to a wide ratio transmission could render first gear useless.....

R

Robert M said:

The 2007-2009's were the same way rpm wise, but with a wider first gear.



R

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I think you have that backwards. The first gear on the early cars is 2.97 which is taller (motor revs faster) than the 2.66 in the 13/14 cars.

The higher # gear is a shorter gear, taller gears have a lower numerical #.

A 4:10 gear is "shorter" than a 3:73 gear.

gimmie11s said:

I think you have that backwards. The first gear on the early cars is 2.97 which is taller (motor revs faster) than the 2.66 in the 13/14 cars.

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2.97 is farther away from 1 to 1, wider gear spread to get to 1 to 1, more rpm drop between gears, wider ratio.
2.66 is closer to 1 to 1, closer gear spread to 1 to 1, less rpm drop between gears, closer ratio.

............and yes, the 2.97 is revving the engine almost 3 times to 1 revolution of the tail shaft and the 2.66 is revving the engine 2.66 times (less than 2-3/4) per one revolution of the tail shaft. Those extra revs on that 2.97 first gear "could" render 1st gear useless because the second gear shift has to come so quick to not over rev the engine........all dependent upon rear end gear and overall tire diameter.

R