Posted: May 02 2007 at 2:22am | IP Logged

I have a '03 XE crewcab with a 5-speed manual transmission. I like the truck, but I only get about 18.0 mpg. The truck is low geared. When I'm doing 70 mph, the engine is turning 3000 rpm's. I'd like to get the rpm's down to about 2000 rpm.

Will a 6-speed manual from a newer frontier help me and will it bolt up and fit without any modifications?

Posted: May 02 2007 at 2:10pm | IP Logged

..

ramjet;

Posted: May 09 2007 at 10:59pm | IP Logged

What you really need is different gears in the rear end, no need to swap the tranny.  my '97 D21 used to tach high too but it had 4.56 (I think) gears, if it had 3.69's like my '05 has it would have been better.

putting bigger tires on will reduce your rpm but it will likely not improve your fuel mileage and going up 2" in tire size is probably only going to lower your rpm by 7%...

Posted: May 17 2007 at 9:29pm | IP Logged

I've got an 03 Crew cab 4X4 with a 5 speed stick. Yes these trucks are geared WAY too high or too low depending on how you see it. My truck has 4:33 gears (from the factory) and in 5th gear at 65-70MPH, I am taching out at just a hair over 3000 RPM. It's not long trip friendly. I love the truck but when we take long trips we use my wife's Honda Pilot.

In my opinion Nissan screwed the pooch with this one. They should have used lower gears, or added an extra gear to the tranny. You're 100% correct on long trips my truck gets horrible gas mileage. Changing the gears is a costly option. My truck is 4X4 and I'd have to change both front and rear gears. That could cost a fortune.

I'm going to be due for new tires before next winter and I'll be stepping up to 31's. Hopefully that will help a little bit. I don't do a lot of highway driving but when I do I hate to cruise at 3100 RPM.

Posted: May 19 2007 at 8:44am | IP Logged

Yeah but if you bolt in a rear with 4.9 gears it will tach out even higher. In order to lower RPM he'd need to go to something like 3:55 gears.

I can live with it. I only live 4 miles from home. My 03 only has 23,000 miles on it and I own it. The truck does tow my bass boat nicely. So I can live with the bad highway mileage from time to time.

Posted: May 19 2007 at 7:50pm | IP Logged

ramjet wrote: Thanks for all your help everyone. I don't know what I'm going to do yet. Heck, I may go to the local dealership and buy a new one. I hear the frontier's have more horsepower and a 6-speed transmission.

way more power and the 6-spd is nice, trust me.  still, dont expect miracles, it's also a larger truck that weighs more.  best tank I've ever had in my '05 is 22mpg (all highway carrying 40 cu ft of mulch) and I'm averaging 18.7 since I got the truck (36k miles so far).

Still, better mpg than my '97 D21 got, twice the power and room for car seats, I cant complain.