I'm thinkin about maybe upgrading the gear ratio in the rearend. Anybody know of a good ratio for better accerlation and speed but low enough for being able to get out of thick stuff if I need to? Also, what rearend is in an '04 SXT reg. cab 3.7?

 

Do you have a 2-wheel drive? Randy's Ring and Pinion worked good for us when we changed the ratios on our old Ford Super Duty.

I haven't looked it up, but I imagine yours would be a 3.55. If you have a 4-wheel drive you will have to change the front and rear which would run into twice the money, at least.

Changing the ring and pinion would probably be the cheapest route, but I wouldn't recommend doing it yourself unless you are have a well equipped toolbox.

 

I've always used randys ring and pinion too. You can look in your glove box as to be sure what you have in the truck now. 3.92's are nice a little bump up. 4.10's will have a lot better acceleration but will be higher rpms on the highway.

 

Count the bolts holding the cover on and it will tell you what size rear end it is.

8 1/4 - 10 bolt
9 1/4 - 12 bolt

As to the ratio, that can vary. There should be a tag on the differential. If not, you'll have to look up the options.

This link will take you to how to get that build sheet:

https://dodgeforum.com/forum/3rd-gen...ild-sheet.html

If it's a 4x4, remember, you need to do the front too.

 

I looked it up, its a 8 1/4 in, running 3.55. Would i have to do the front and rear as the same even if I don't leave in 4x4 all the time, and barely use it?

 

Yes, you need to do both, unless you remove the front driveshaft and never use 4 wheel drive.

As for what ratio to recommend, we would have to know your tire size, transmission, engine, and planned usage (city, highway, off-road, towing, etc.)

 

i have a 2001 dak V 6 3.9. 2 wd, it had a 3.55 and was getting poor MPG. i drive in town only. i had my mech change it to a 4.1 gear and posi. i thought i might as well have power. after ward the MPG went better by 4 points. only cause i drive in town only. and it would go into O.D. at 30 MPH. with lite throttle. i have all the part nos if you want i can post them. also it didnt change the speed O. allso the great guys here helped me deiced to use on a 4.1 gear and not a 4.56. thanks to them, they are the greatest. edit add part numbers.

i just had my V-6 2001 dak changed from 3.55 to a 4.10. my friends here told me i DONT want 4.56s. iam very happy with my 4.10. my MPG went from 9 to 13, in town ONLY. cause the trans shifts it overdrive at 35 mph, that gives it the 13 mpg. i do not think you will like 4.56, unless its a street racer.*
1.motive*gear*4.10 gears C8.25-4.10,
2. dana/spicer locker 84852
3. install kit DRK303B, 4. 75W90 synthetic*gear*lube VV975. my shop would NOT give the swap any warranty.

 

Why was this?

 

Seems a little odd they wouldnt give a warranty.

 

That's what I was thinking. I wouldn't use a shop that won't warranty their work.