Finally got my 3.73s installed!

[93 347 Cobra]

I took my car into a drivetrain shop and the owner is a classic Ford guy. It took them the whole morning but it was fine because I was able to get work done remotely while I waited.

The car feels worlds better than with the 3.31s! This is really how it should have come from the factory. The shift points feel more natural and much closer to how my '03 Cobra felt with 3.55s. Coming off the clutch was much easier from a stop. Dark clouds were overhead and it was starting to spit rain so I wasn't really able to pound on it much. I'm letting it cool off before driving it a little more.

Overall I'll echo what others have stated, this should be one of the first mods made to the car. It's an immediate night and day improvement. I'll update later in the weekend as I get further impressions. There is a very very faint whine at part throttle on the highway but it's nothing that's very noticeable at all and certainly not to the degree that I would take the car back in for. My 3.31s were stone silent unless going up an incline at light throttle at highway speeds.

 

[paluka21]

I took my car into a drivetrain shop and the owner is a classic Ford guy. It took them the whole morning but it was fine because I was able to get work done remotely while I waited.

The car feels worlds better than with the 3.31s! This is really how it should have come from the factory. The shift points feel more natural and much closer to how my '03 Cobra felt with 3.55s. Coming off the clutch was much easier from a stop. Dark clouds were overhead and it was starting to spit rain so I wasn't really able to pound on it much. I'm letting it cool off before driving it a little more.

Overall I'll echo what others have stated, this should be one of the first mods made to the car. It's an immediate night and day improvement. I'll update later in the weekend as I get further impressions. There is a very very faint whine at part throttle on the highway but it's nothing that's very noticeable at all and certainly not to the degree that I would take the car back in for. My 3.31s were stone silent unless going up an incline at light throttle at highway speeds.

Agreed, the 3.73 gear in this car feels great and keeps the car in a more desirable rpm range when shifting.
The whining may come later after you pound on it some and/or do some harder launches. Mine were dead silent for about 400 miles until I laid into it in 1st and 2nd.

 

[93 347 Cobra]

Agreed, the 3.73 gear in this car feels great and keeps the car in a more desirable rpm range when shifting.
The whining may come later after you pound on it some and/or do some harder launches. Mine were dead silent for about 400 miles until I laid into it in 1st and 2nd.

I hope it doesn't get worse. I romped on it stock when new from a stop at about 500 miles and the gears were always dead quiet.

 

[efroeh]

i am considering this mod, look forward for you impression after a few miles on her.

 

[Norton]

i am considering this mod, look forward for you impression after a few miles on her.

That makes two of us. Sent you a PM, 93 347 Cobra...

 

[Eleanor14]

My car is begging for a 3.73. The only reason I held off is the whining I keep hearing about it... Every single mustang I've had has had gears and my daily driver also has 3.73's and a whine. The GT500 is dead quite so far, so I've been holding off, but I don't know for how long.

 

[Ablaze]

May get flamed a bit for this but that's why I've every intention of doing 4.10s. Ran 4.10s in every mustang I've had and never had a whine. I always stomped on the gas the second I picked the car up, never any break in. I know people say it has nothing to do with the gear ratio but, what can I say..

 

[paluka21]

I know people say it has nothing to do with the gear ratio but, what can I say..

It really doesn't. The 4.10's have the potential to whine just as much as any other gear put in the 8.8. Some of the guys on here have went through re-shimming the gears, different weight gear oils, and break in periods and still get whine. There are a few that don't.
IMO, even though the gears whine, it's still worth it. This car isn't a Cadillac or a luxury car, so a little gear whine to me isn't a deal breaker for the performance gains they yield. A 3.73 gear in this car feels like it belongs in the car from the factory, and is a great bang for the buck.
Like you, I've had other 8.8s with gears that never had whine, but this one seems to be the exception.

 

[Willie2]

You guys just about have me talked into this mod

 

[Matt in Houston]

4.10's are awesome too. Its not too much, especially if you are running a tall drag radial out back. I also loved the 3.73's but after driving both, I prefer the 4.10's. Both gears feel much better than the stock 3.31's. Those on the fence need to give it a shot!

 

[NELCO]

Please tell me how you are not spinning the tires with the 373's.

 

[Matt in Houston]

^^^^ BMR Rear Suspension - Eibach Pro Kit - Forgestar F14's - 305/45-18 NT05R

Helps a lot...

 

[biminiLX]

4.10's are awesome too. Its not too much, especially if you are running a tall drag radial out back. I also loved the 3.73's but after driving both, I prefer the 4.10's. Both gears feel much better than the stock 3.31's. Those on the fence need to give it a shot!

X2
Love 4.10s on DRs!
-J

 

[efroeh]

I have some gear whine with my stock gears. Guys with 373 are they noticeable loud? Wanting to do a long distance drive and I think a loud whine would be annoying.

 

[Live Faster]

I have some gear whine with my stock gears. Guys with 373 are they noticeable loud? Wanting to do a long distance drive and I think a loud whine would be annoying.

I have gear whine on stockers as well. Just did a 5 hour trip in my car and only time I notice the whine is when letting of the pedal and coasting in 4th or 5th.

 

[Ablaze]

4.10's are awesome too. Its not too much, especially if you are running a tall drag radial out back. I also loved the 3.73's but after driving both, I prefer the 4.10's. Both gears feel much better than the stock 3.31's. Those on the fence need to give it a shot!

I'll be running the 4.10s with stock size R888s in the rear. I'm sure it will be quite an experience.

 

[93 347 Cobra]

That makes two of us. Sent you a PM, 93 347 Cobra...

Back at ya.

You guys just about have me talked into this mod

I think these cars are pretty close to perfect from the factory. They just need gears, res delete, and throttle body (only because it picks up insane power for such a straightforward bolt-on).

I have some gear whine with my stock gears. Guys with 373 are they noticeable loud? Wanting to do a long distance drive and I think a loud whine would be annoying.

Some guys who have made hard launches at the strip or street on drag radials have gotten noticeable whine. Early on mine are almost silent.

I put on another 15 miles earlier this morning and the car just puts a smile on my face. It was in the low 50s this morning and on stock F1s traction was already a major issue but is much more so now. The tires don't let go so quickly but more easily if that makes any sense. I expect the ass-end to slide around a bit in colder temps so it was no big deal. I haven't gone WOT in 1st and won't do so until I drive it for another few hundred miles. I ran the car to about 120 from 60 and on the 3 to 4 shift around 110 the ass-end twitched. I need some better tires or warmer temps so these F1s actually grip.

A few other items to note: 1) I did not need the side bearings replaced as they were in excellent shape with only 12.8k on the clock so the OE part number installation kit I ordered was perfect for the task 2) As has been stated before by others the OE part number gears are EXACTLY the same as FRPP gears, same markings and everything 3) As stated by others in a few posts on previous threads Motive did indeed make the gears in some of the FRPP gears from a few years ago that are not as high quality as the Ford gears (shop owner verified this)

 

[07 Black Beauty]

Dammit another thing to add to the list.