I've gotten the mod bug again, and this time it's biting for drivetrain upgrades.

What can you guys tell me about 4.10 gears in an otherwise stock S197GT Auto?

Benefits/risks/other-needs? I'm not much more than a noob when it comes to doing this kinda stuff, so lay it on. I want to know everything. My 'Stang's a daily driver, so while I want the best performance, I also don't want to sacrifice driveability, etc.

Also, where's a good place to get 4.10's, what's the best brand, and how much did some of you pay to have them installed?

</naive>

 

I love my 4.10's, but my car is a manual. You'll probably want a different ratio for automatic.

I'd recommend you let the shop that is going to do the install buy the gears. If I recall (it's been a while) I paid somewhere around $500-600 for the gears and installation.

 

Good advice...if something goes wrong with it, they can't blame the gears you bought, etc. Id say make sure they are the rear end parts that need to be replaced with new when thgey do the install....and I can't list them cause I don't know them all.. but you get the drift.

 

The overdrive ratio is taller in the manual. This will effect your highway driveability some. The OD ratio for the auto is 0.71, the manual is 0.675

Assuming a 27.1" tall tire and 4.10 gears rpms will be:

2500 @ 69.24 mph with the auto
2500 @ 72.83 mph with the manual

This is why the manual folks tend to go with 4.10s more readily because of the difference in the OD ratio.
Change that to a 3.90 with the auto and you get 72.79 mph at 2500 rpm with the auto.
Hope that info helps with your decision.

 

Ow...my brain just backfired...

So you would recommend 3.90?

FRPP offers a 3.73. Motive offers a 3.90.

I may be able to swindle a good deal from my dealership, which will probably mean I'd go with a FRPP part. Opinions on the 3.73?

 

Maybe you already have, and I don't mean to sound like a jerk- but try the search feature, there is a BUNCH of info on 4.10s, etc. for both auto and manual trans cars.

FWIW, I love my 4.10s; I have a manual but there are many people that have them with the autos who love them too.

 

I'm one of them... auto trans and 4.10s for almost 30K miles now.

 

So between the 3.73 3.90 and the 4.10's are any riskier when concerning the transmission? I am thinking about doing the 3.73's but the 3.90's sound good and ive talked to some auto guys with 4.10's that love them.

 

I have an auto with 3.73's. I am pretty happy with them. I would have went with 4.10's but I am adding Whipple next and I think the 4.10's would have been a little much with a supercharger.

 

I wanted to do 4:10s in the wife's vert, but I was advised to go no more than 3.73s without modifying the trans. This is from the local Mustang guru here in the Milwaukee area. He just did a beautiful job tuning a friends 07 Auto with 3.73 and a Novi. If you ever add a S/C you may want to think about doing the 3.73s now. Compared to the 3.31s I'm sure you'll be plenty excited with 3.73. My manual car has the 3.55 and I just as soon leave it alone for now. I'm planning on a Whipple at some point.

 

if you go with 3.73 and run a larger DR tire for traction that will put your gears at an actual 3.55, or at least thats what i heard. 4.10's are amazing speaking from experience. if your worried about the ratio, run a larger tire than stock and it will bring the ratio down to 3.90 or so. IMO run 4.10 an you cant go wrong, but then again im a manual.

 

just get the 4.10's and don't look back. I got 4.10's in my manual and I wish I had just bit the bullet and gone with a 4.33. wakes it right up!!!

 

I love the 4.10's in my auto. If you do alot of highway driving then you might want the 3.73's. 98% of my driving is in the city so the 4.10's work great. You do need to turn off your OD when driving in city or the car will feel very sluggish if you punch it, but with the OD off, it screams. JMHO though.

 

My 3.73's went in a couple of days ago and I am more than happy with them.