I got under my truck and was looking at the gearing and I have 4.30 gears in a 4x4, CC so 18.65 mpg is not bad. But I'm looking at a overdrive unit for the truck. One of my buddys put one in 3 months ago and his mileage went from 18mpg is running around 26 to 28mpg Hwy. He said for "3k for the unit and the price of fuel it will pay for its self in less then a year" and he's right.
best mileage from a powerstroke
- Thread starter 06cumminspower
- Start date
Brad B
Full Access Member
How hard was it to put on and where did he buy it from?
4WD units are mounted between the primary transmission & transfer case, Name is "High Impact transmission & Gear"
DualRange Overdrive
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Crumm
Fordoholic
25 is what I have "heard" and 20 is what I believe. I saw 18 years ago before I added oversize tires. Truck in current form is doing good running mid 16's empty and 10-12 loaded. When listening to mpg figures on a forum you need to work the % a little as in there is probably a 20% increase in mpg on the forum over real life numbers
MONSTERPLOW
Cloud Booster 500HP
21 here lowriding with a zoodad mod
Brad B
Full Access Member
Sounds great. But how hard is it to put in? !!
Also, how do I figure out what ratio I have now ??
I think you guys need to read
http://www.superdutydiesel.com/foru...unge/14319-out-powerstroke-business-rant.html
and
http://www.superdutydiesel.com/forums/7-3l-powerstroke-power-performance/17821-chips-down.html
I believe these trucks get their best economy between 45 & 62mph.
It also helps if you draft the 18wheeler in front of you. Big truck drivers hate that, but not much I can say about it. Fuel is expensive.
My CB antenna is mounted over the rear seat passengers heads, and it whistles on the highway.. I creep in behind the trailer untill the antenna quits whistling.. Did that one day, watched the overhead Lie-o-meter gain a full mpg in 30 miles.
http://www.superdutydiesel.com/foru...unge/14319-out-powerstroke-business-rant.html
and
http://www.superdutydiesel.com/forums/7-3l-powerstroke-power-performance/17821-chips-down.html
I believe these trucks get their best economy between 45 & 62mph.
It also helps if you draft the 18wheeler in front of you. Big truck drivers hate that, but not much I can say about it. Fuel is expensive.
My CB antenna is mounted over the rear seat passengers heads, and it whistles on the highway.. I creep in behind the trailer untill the antenna quits whistling.. Did that one day, watched the overhead Lie-o-meter gain a full mpg in 30 miles.
Gear Vendors double overdrive transmissions is one of the better known "overdrive" units.
cost 3100+ bucks (install & drive shaft work extra) they require the driveshaft to
be "professionally" shortened.
cost 3100+ bucks (install & drive shaft work extra) they require the driveshaft to
be "professionally" shortened.
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BJS
Full Access Member
Installation from the apparatus part is a bit of wiring for the electric shift motors and the installation of a transfer case. As has already been mentioned you'll need to lengthen the front driveshaft and shorten the rear driveshaft.
There are two major vendors for aftermarket overdrives US gear and Gearvendors.
US gear is a gear driven unit if you're 4wd then it goes between t-case & transmission and requires modification of both driveshafts. The internal workings are very similar to a manual transmission. This can be used in 4wd for whenever you'd need that. Dual Range Auxiliary Transmissions, Overdrive and Underdrive
Gearvendors is setup and designed with planetaries and clutches very similar to an automatic transmission. This one replaces the tail shaft of the transmission (2wd) or the tailshaft of the transfercase (4wd) and only requires modification of the rear driveshaft. Obviously you cannot use this on in 4wd. Gear Vendors under/overdrive transmissions the most awarded auxiliary transmissions.
I know people with both and the gearvendors has a more refined shift characteristic like an auto trans, the US gear engages a bit more roughly but no worse than shifting a manual transmission by a skilled driver.
I've seen people who have toasted the gearvendors clutches behind the PSD and others who love them and have had no problem both with similar power & loads. I noticed now that gearvendors is putting a 2yr unlimited horsepower warranty on the units which they didn't have when I looked several years ago.
For the ratio. use what you know about your truck and the calculators found here.
I suggest using the convert p-metric to tire diameter calculator at the bottom to start with then move to find MPH.
Your rear axle ratio is either 3.55 or 4.11 or those are what came factory and given that you say you're on your 4th transmission I'll presume that it's an auto the OD ratio is .73 (I believe) or you can lock OD out and your in drive and just use 1 for both trans & t-case numbers
FWIW.. I had a GV unit on my 91 IDI, 5 speed, 4:10s, 2WD. After installing everything ATS had to offer in those days, the GV overdrive unit fixed the.. Power verses Gearing issues I had when towing our 5r..... by being able to "split" the gearing.
Did the install myself, except the D=shaft shortening. IIRC, I had about 2K invested, in 90's dollars.
Towed in 4th Over. Much, Much better, more stay'n power. MPG's went from 10 to 12+ towing, 18 to 20+ empty. 5th over was Nice.
Had the GV on for about 150+K, NO issues.
I'm in contact with the guy I sold " 'Ol Blue" to.. he's still in service.. as a Wrecker/Tow Truck. GV still work'n.
Did the install myself, except the D=shaft shortening. IIRC, I had about 2K invested, in 90's dollars.
Towed in 4th Over. Much, Much better, more stay'n power. MPG's went from 10 to 12+ towing, 18 to 20+ empty. 5th over was Nice.
Had the GV on for about 150+K, NO issues.
I'm in contact with the guy I sold " 'Ol Blue" to.. he's still in service.. as a Wrecker/Tow Truck. GV still work'n.
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