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2001 Dakota r/t trying to gain fuel mileage by swapping gears

6K views 12 replies 7 participants last post by  hskrRT 
#1 ·
Bought the truck thinking it would get 18+ mpg,,,,not so looking at 13

Been doing some research and for the 9.25 rear end the most highway gears I see is 3.21 or possibly 2.97.

I plan to drive this thing more highway than anything and not interested in drag racing it or anything like that.

Just thought it was a cool little truck so bought it.

Anyone know and what impact (highway) such a drastic change in gear ratio will do for fuel mileage?. I know most people are going the other way to get better performance.

Thanks
 
#2 ·
I went from 3.55 to 3.9 or 4.1 - I forgot. I think I lost .25 per mile. You won't recover the cost of the gear change in mpg savings. Do the basics first, new spark plugs, wires, cap, rotor, change to synthetic fluids everywhere, gunk fuel system cleaner Then see what your mpg is.
 
#10 ·
I went from 3.55 to 3.9 or 4.1 - I forgot. I think I lost .25 per mile. You won't recover the cost of the gear change in mpg savings. Do the basics first, new spark plugs, wires, cap, rotor, change to synthetic fluids everywhere, gunk fuel system cleaner Then see what your mpg is.
Don't forget a wheel alignment.

That is about everything you can do.

Air temp and gas formulation affects mpg also.

I get 17/18 in suburbia and 20 on the highway at 60mph. That is about the best someone can do with my set up and near the advertised mpg when new.
 
#3 ·
You aren't going to get anywhere near 18+mpg in mixed driving. With all my mods I get about 16-17 all highway which is better than I got stock and I have 4.10 gears. If anything the lower gears will actually hurt mileage some as the motor will have to work harder to get the truck moving. Don't buy a Dodge truck if you want decent gas mileage.
 
#5 ·
Research is everything if gas mileage is your goal. I sort of wanted "cake and eat it too" with my Dakota, so I bought a 4.7 5-speed manual. After 13 years, it still gets 19 -20 mpg. I almost bought an R/T in 2001, but I knew most R/T owners got 15 at best, and I drive an average 28K a year. Here in hilly East Tennessee, owners of 3.9 Daks get less mpg than me.
All is not lost for you, however. Try some of the classic mpg tricks on your R/T:
Synthetic oil in engine and rear end.
Good cold air intake.
Free flowing exhaust (big y-pipe/ hi-flow cat/ muffler/ pipes.
High pressure tires.
I run a set of R/T wheels with Kumho Venture 275/55/17 tires set to 46 psi, which is 5 psi under max rating. The tires are 1" taller than the stock R/T 28" tire, and should help your interstate mileage. If you have a Superchips program, you can adjust the speedo yourself each .25" tire height.
I always wondered if a 2004 3.7 Regular Cab would be a ultimate mpg Dak.
A bitchin mod would be a new 3.6 with a 9 speed tranny LOL.
 
#6 ·
Research is everything if gas mileage is your goal. I sort of wanted "cake and eat it too" with my Dakota, so I bought a 4.7 5-speed manual. After 13 years, it still gets 19 -20 mpg. I almost bought an R/T in 2001, but I knew most R/T owners got 15 at best, and I drive an average 28K a year. Here in hilly East Tennessee, owners of 3.9 Daks get less mpg than me.
All is not lost for you, however. Try some of the classic mpg tricks on your R/T:
Synthetic oil in engine and rear end.
Good cold air intake.
Free flowing exhaust (big y-pipe/ hi-flow cat/ muffler/ pipes.
High pressure tires.
I run a set of R/T wheels with Kumho Venture 275/55/17 tires set to 46 psi, which is 5 psi under max rating. The tires are 1" taller than the stock R/T 28" tire, and should help your interstate mileage. If you have a Superchips program, you can adjust the speedo yourself each .25" tire height.
I always wondered if a 2004 3.7 Regular Cab would be a ultimate mpg Dak.
A bitchin mod would be a new 3.6 with a 9 speed tranny LOL.
hahahah aint that the truth
 
#8 ·
My quad cab is getting 15 mpg here in Atlanta. I would say mixed but I spend a LOT of time crawling in heavy ATL traffic. Plugs are new, tires pressure at 33 lbs. Synthetics all around. Gas prices are good so I'm driving the truck a bit more. Mostly I drive an Accord.
 
#11 ·
Thanks for all the replies

All things I plan to check and possibly do.

Most of my miles >75% will be interestate so I will try it anyways.

Does anyone know what the most highway gears specifically for my 01 r/t 9.25" rear end I can get to install in my truck.
 
#12 ·
While I liked the truck a lot and it is a cool little vehicle a few things made me decide to dump it.

It runs great but:

1) Intake plenum gasket failed (oil consumption, O2 sensor, oil consumption up the wazzoo
2) water pump started to squeal
3) front seal started to drip
4) steering wheel creaking (column) I thought it was interior trim when I bought but getting worse
5) slight knock in tranny
6) I did change the power steering pump hoses

All at 114k miles??? sheesh, I took a chance on buying another Dodge when my Spidey Senses told me for years that Dodge reliability is questionable, should have stuck with my gut.

Oh well picked up an 08 Chevy base model.

Thanks for the replies to all.
 
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