I'm gonna upgrade my gears (hopefully at the end of the summer) and want to do 3.42:1. As a better "all around ratio". But a lot of people have told me to get 3.73:1. Going from what I have now, to that is a BIG jump. I've also been told that from 3.42:1 to 3.73:1 there is no difference on the freeway. Which doesn't make any sense to me. the higher you go (numerically), the LESS top end you have. I do a lot of freeway driving, and I don't want a huge exhaust drone from constant high rpm.


So, 3.42:1 guys, what rpm at 80 mph?
3.73:1 guys, what rpm at 80 mph?

 

Try this sight and plug in the numbers, it will tell you everything you want to know:

http://www.f-body.org/gears/

Go with the 3.73's, you will love them.

SteveC

 

Um, i'm not sure how to work it.

 

3.42 2500 RPM @ 80

3.73 2700 RPM @ 79

 

What rpm at 100, 125, and 140?

for both ratios

 

3.42 - 3100, 3900, 4400
3.73 - 3400, 4300, 4800

 

IMO, stick with 3.42's if you do a lot of highway driving. The difference may not be a lot, but the 3.42's will give you a little extra speed in each gear, but they'll still pull a lot harder off the line. Compared to my car with 2.73's, it's got a real bad "dead spot" out on the highway at around ~70 mph. When you hit it, it won't drop out of OD (4th), only the converter comes out of lock-up, so it doesn't pull all that hard, whereas with 2.73's, it would still drop back to 2nd gear at that point, and pull like a bat out of hell 'til over 120 mph!!

My friend installed 3.42's into his '96 T/A and he loves them. I love the 3.73's in my car off the line, but they're too much for the highway IMO. I say get 3.42's from the sounds of what you want .

 

can you explain the 70 mph dead spot on the 3.42?

 

I'm not sure where the dead spots would fall for a 3.42 car, but my 3.73 car has a couple (somewhere around ~40 mph, and again around ~70 mph).

When I say "dead spot", what I mean is that when you punch the accelerator to the floor, the transmission may not downshift as far as you would like, or maybe not as far as it would have with 2.73's. When doing 70-75, when I hit it, the torque converter comes out of "lock-up" mode, but the transmission stays in 4th gear (OD). This makes it accelerate rather slow, especially compared to having 2.73 gears that will downshift to 2nd gear at 75 mph!! I would think that a car with 3.42's wouldn't suffer a bad dead spot 'til closer to 80 mph (since they're a slightly higher ratio).

I've heard from some guys that if you get a stall converter, it will pretty much eliminate those dead spots by allowing the engine to rev higher and pull the car up through those dead spots.

 

well, I was almost convinced to go to the 3.73, but I do LIKE my freeway FUN. So, the less dead spots the better. Thanks.

 

Downshift problems are caused by bad programming. It's not because of the gears. On average 3.73s pull better from the roll than any lower ratio. If you fall into dead spot the time spent there is shorter when you have higher gear. Of course you will find cases where each gear performs best. My car still shifts to 2nd at 60 mph and to 3rd below 100mph and that's with 3.73s.

 

Terve Pekka!