I have a 2004.5 6MT sedan. I have done a lot of reading on differentials and gearing lately and have thought about going from 3.54 to 3.69 final drive. I have seen lots of people that have gone from 3.3 final drive to 3.5 or 3.7 final drive but I can't seem to find anyone that has gone from 3.5 to 3.7.

I don't want this to turn into a you'll lose CC debate like some of the other threads I've come across.

 

3.54 to 3.69 isn't that big of a jump honestly. I'd suggest that you go to the 3.9 at least.

 

That's what I'm thinking... the 3.36 to 3.54 isn't that much of a jump either, but people are extremely happy with it.

 

Time for more research lol

 

+1. If you are going to spend the time/money for a fd swap I wouldn't mess with 3.69 gears. Since you have the 6MT the 3.9 or 4.01 is the way to go (assuming you are NA and don't plan on FI in the future).

 

You'll be doing a looooot of shifting with a 3.9!

 

Yeah, I know. If I can find a 3.69 pumpkin for cheap thats the road Ill take. I do plan on FI in the future and dont want 3.9 gearing.

 

Easier to skip gears??

 

go big or go home,

 

^^ +1 haha my friend has 4.77 on his s2k and its an ap2 btw and man he'll be going like 60mph at like 5200-5600 rpm in 6th gear but he's really happy soo i dont blame him

 

WTF??? No way that's crazy I thought it was crazy enuff in my b20 with ctr tranny. 4th maxes at like 85 with stock 6500 limit Lolz. But after I could go up to 8500 it was all good lots of head room.

I think 3.5 to 3.-7 only shortens u like 2-3 mph per gear. Not that much of a difference for the time n money.

 

for MT, 3.5 to 4.0 (4.0 is oem is cheaper than 3.9)... AT 3.3 to 3.7

I know you said you dont want to go 3.9 or 4.0 - but I wouldn't get a mod just because the deal is good, it probably isnt worth the time or cost (as little as it may be) to go 3.5 to 3.7

Just my .02

 

I'm not following your reply . He wants a 3.7 and nothing more. He mentioned he plans for F/I in the future, so going too short in the gearing isnt good. A 3.7 will benefit him over the 3.5 (Btw OP if you do swap out your 3.5 let me know). He isn't looking to save money, just looking for insight on the 3.5 - 3.7 which I unfortunatly cant answer.

 

I'm bumping this back up because I'm interested again and the differentials have become easier to find and are cheaper.

It appears that if I find a 3.692 differential from a 6mt car the swap is direct except the ABS sensors need to be swapped over. Can anyone confirm this?

 

3.5 to 3.69 is not that much of a jump really. Have you done RPM calculations to see where your RPM's will shift to?

I just did a quick calc (read: may not be accurate) and it's only a 100RPM difference at 70MPH. I honestly doubt you'd feel a difference there in total acceleration.


I went from 4.10 down to 3.73 in my Mustang and wasn't really that impressed with the difference. Fortunately the swap cost me $150 total since i did the labor myself and parts are cheap.