4.10's auto - 3.73 stick?

[SPDU4IA]

Why do most people suggest putting 4.10's in auto's over 3.73's? Does the AOD rev at a lower rpm at higher speeds than the stick? Or does an auto with a shift kit make up for having the crappy shifts that would best be suited with the 4.10's?

 

[Josh94gt]

Well I don't know for sure, but since the Auto is a 4-speed and the Manual is a 5-speed I would think that the Auto's gears have different ratios which down low reduces the torque multiplication - so yeah lower rpms for higher speeds. The MAIN reason is because the auto uses up more horsepower, so the 4.10's make up for that hp loss by increasing torque. A lot of ppl on here run 4.10's on daily drivers or even 4.30's. Even ppl with manuals do...

 

[Mrgreen94gt]

There is more or less a combination of reasons for selecting 4.10 for autos and 3.73 for manual, I'd probably use 4.10 in either case. The reason that stands out the most would be the difference in 1st gear ratios, around 3.35 for the T5 and 2.40 for the AODE & AOD. Many feel that the deep first gear of the 5spd offers more than enough initial gearing when paired with a 3.73 rear ratio.

How much power the vehicle has, the weight of the vehicle, and other things would come into play when deciding what ratio to use.

 

[SPDU4IA]

4.10's it is

Thanks for the great info. I've pretty much made up my mind now to go with the 4.10's

 

[HazMat404]

with an auto definately go 4.10. im still kinda torn on my 4.10 in my manual. at times i like it and at other times i wish i had a lil different. i just need to drive a stick with a 3.73 and near the same mods as me

 

[SPDU4IA]

I was just pondering that with the different ratio's in each gear from the auto to the stick, would they have very comparable top ends in each with the 4.10 in the auto and the 3.73 in the stick?

 

[95tealGT]

The reason I went with 3.73s in my auto is because we have 3 speeds and I now have a top speed of around 115 or so. If you go with 4.10s this will be even lower, and you'll have to go with a taller tire at the track if you reach speeds higher than this. If you even consider going WOT on you'r O/D say goodbye to your tranny.

 

[SPDU4IA]

So then would 4.10's best be paired with a tire size of 275/50R17(27.83in diam) instead of 275/40R17(25.66in diam)?