change to 6 spd. or install overdrive?

[corvette_dad]

i have a 98 Chev. 2500 4x4 with a 6.5 td and 5spd manual. i was thinking bout changing to a 6 spd to try to get a little better highway mpg. or would an add on overdrive be better? also thinking about getting a reprogramed ecm. any suggestions?

 

[THEFERMANATOR]

i have a 98 Chev. 2500 4x4 with a 6.5 td and 5spd manual. i was thinking bout changing to a 6 spd to try to get a little better highway mpg. or would an add on overdrive be better? also thinking about getting a reprogramed ecm. any suggestions?

A 6 speed wouldn't really lower your highway cruising RPM's much if any. Most of the time a 6 speed has roughly the same 1st gear ratio and OD rtio, the gears in between re simply closer ratio is all. An updated ECM program can help your milage some as well as an intake and exhaust. Fill out your sig so we know what you have.

 

[corvette_dad]

i was thinking Kinsler has a 6spd. double od with a .64 or something 6th

 

[Anubis]

I'd go with the OD..... Ranger torque splitter or a gear vendor.


you would then have 10 gears with the proper gear spacing and triple OD.

 

[THEFERMANATOR]

Not to try and derail your upgrade plans here, but why do you want to? Is it strictly to lower your highway RPM's for better milage? If so it will take a LONG time to re-coup the upgrade costs in fuel savings. You need to decide what you want to use the truck for and go from there. If you're after highway only with minimal towing then a set of 3.42 or even 3.08 gears would give you good milage and low highway RPM's. And a gear swap will be cheaper than a trans swap unless you can get a smoking deal on a used unit from somebody.

 

[GM Guy]

I would agree with The Fermanator. Why do you want to do this? If it is to lower revvs for fuel economy, I see fender flares (4wd), so that means 2 pumpkins rather than one await gears, which is still half affordable compared to a Gear Vendors.

The Gear Vendors unit is awesome, but awesome costs money, and lots of it.

There are many double OD transmissions out there, but IDK if any can mount to a t-case. The ones that come to mind are the corvette trannies, but you would have to launch in 4 low because 1st is so high geared.

I personally would stick with the NV4500 you have now and pursue a gear swap.

Good luck, and whichever path you choose, make sure there is a right hand deciding the gears! :thumbsup:

 

[corvette_dad]

the gear change may be the better way to go. my son also suggested that. it's my daily driver and i would like a little better economy.

 

[tracker954x4]

Another possibility might be that its time for that cat to come off there. Its a good possibility that it could be getting restricted, especially since its got almost a quarter million miles on it. I wouldn't go crazy with swapping gears, cause what you might gain in fuel economy, you stand to loose more in performance and useability.:thumbsup: