Overdrive conversion??
Posting Guru
Joined: Jul 2004
Posts: 1,627
Likes: 0
From: West Valley Utah
The Gear Vendor unit is very reliable. They have tested them in the summer on motorhomes pulling trailers in the Mojave Desert according to the people I talked to at Gear Vendor. I do have an overdrive unit on my 86.
You don't "need" to use a clutch or back off the throttle to shift. However, the harshness of the shift does change depending on how heavy you are on the throttle, loaded, unloaded. It also has 2 modes, automatic and manual. In auto the trans goes through it's normal shift pattern until a predetermined speed and then the OD shifts. In manual, you choose (using the foot switch) when and what gear you want to shift in. You can split every gear if you choose.
I've never had a problem with the unit it's self but I did have a speed sensor go bad about 4 years ago. Traveling 75 mph and then have the OD suddenly drop out and engine rpm wind up to the nutz does NOT give you a warm, fuzzy feeling.
You don't "need" to use a clutch or back off the throttle to shift. However, the harshness of the shift does change depending on how heavy you are on the throttle, loaded, unloaded. It also has 2 modes, automatic and manual. In auto the trans goes through it's normal shift pattern until a predetermined speed and then the OD shifts. In manual, you choose (using the foot switch) when and what gear you want to shift in. You can split every gear if you choose.
I've never had a problem with the unit it's self but I did have a speed sensor go bad about 4 years ago. Traveling 75 mph and then have the OD suddenly drop out and engine rpm wind up to the nutz does NOT give you a warm, fuzzy feeling.
Fleet Mechanic
Joined: Sep 2005
Posts: 1,509
Likes: 3
From: Ladner, British Columbia
Thanks, that is good information. I would appreciate it if you had any fuel economy numbers. As towing numbers can vary depending on load, a no-load kind on run for either city or hwy would be what I am looking for. My 91 7.3l with the E4OD and 4:10 gears is getting 14.3 mpg city. My thought is that the double overdrive could improve that to maybe 16 to 17 mpg.
Hotshot
Joined: Feb 2004
Posts: 11,697
Likes: 3
From: Marengo, Iowa
My understanding on the engine braking issue is that you just don't want to leave it in overdrive when doing engine braking. If run on automatic, it may do it on it's own, I don't know, but basically, you just turn it off, which takes it out of overdrive, and you can do engine braking that way, so as far as I am thinking, that would be ok in that you really don't want to be in overdrive trying to slow your rig down anyway. That is my take on it anyway.
Mountain Pass
Joined: Sep 2004
Posts: 146
Likes: 2
gear vendors vs. u.s.gear
gear vendors all the way. i currently have a usgear o.d. unit in my 91 f350 (came with the truck) shifts like the old truck two speeds, hit the switch, let up on throttle, BANG, it switches. feels like the tranny just dropped out. if i'm pulling my trailer i won't change it unless i'm on level ground, and then it's still harsh.
i did have a gear vendors on my 89 one ton chevy 454 w/turbo 400 (which i sold when i got my diesel) you can shift it in and out of overdrive loaded or empty on the flat or in the hills, it doesn't matter, you will have a smooth shift everytime. i had thought about swapping the two before i sold my gasser until i found out the price of the adapter kits to chang them over. i did see a gear vendor listed locally for $1750.00 out of a ford but i'm not ready to spend that kind of money since i already have th u.s.gear unit. i just make sure i shift before i get to the hills.
i did have a gear vendors on my 89 one ton chevy 454 w/turbo 400 (which i sold when i got my diesel) you can shift it in and out of overdrive loaded or empty on the flat or in the hills, it doesn't matter, you will have a smooth shift everytime. i had thought about swapping the two before i sold my gasser until i found out the price of the adapter kits to chang them over. i did see a gear vendor listed locally for $1750.00 out of a ford but i'm not ready to spend that kind of money since i already have th u.s.gear unit. i just make sure i shift before i get to the hills.
Fleet Mechanic
Joined: Sep 2005
Posts: 1,509
Likes: 3
From: Ladner, British Columbia
Thanks Banks73,
That is good information. I will have to keep my eye out for a Gear Vendor. Maybe one will pass thru the wreckers one of these days. You never know.
I agree the Gear Vendor is the way to go hand down.
That is good information. I will have to keep my eye out for a Gear Vendor. Maybe one will pass thru the wreckers one of these days. You never know.
I agree the Gear Vendor is the way to go hand down.
Tuned
Joined: Oct 2004
Posts: 250
Likes: 6
From: new york
I just got back from a short trip, 155 miles each way. Total miles 310, after filling the tank with all it would take 12.8 gallons. It worked out to just over 24 miles per gallon. I ran cruise control at 65 for 3/4th of the trip as it was mostly expressway travel.
My truck is a 91 extended cab two wheel drive with an E40D with 410S, but I also have a Banks Sidewinder and a Gear-Vendor overdrive unit wired to run in overdrive with the E40D overdrive, giveing me double overdrive. Which works fine for cruiseing around in an empty truck.
This is the first time I have ever checked the mileage, I know a couple of you have asked, but because my boss gives me off road fuel for free I never bothered. This time I took a friend to pick up his truck he bought on ebay and he was buying pump fuel, I did drive a little more cautiously just to see how many mpg I could get and made sure it was round trip to make it as realistic as possible. By the way my friend bought a 92 7.3 4X4 extended cab with 208K for $2600. Sharp truck, has some rust but in NY almost everything does!
My truck is a 91 extended cab two wheel drive with an E40D with 410S, but I also have a Banks Sidewinder and a Gear-Vendor overdrive unit wired to run in overdrive with the E40D overdrive, giveing me double overdrive. Which works fine for cruiseing around in an empty truck.
This is the first time I have ever checked the mileage, I know a couple of you have asked, but because my boss gives me off road fuel for free I never bothered. This time I took a friend to pick up his truck he bought on ebay and he was buying pump fuel, I did drive a little more cautiously just to see how many mpg I could get and made sure it was round trip to make it as realistic as possible. By the way my friend bought a 92 7.3 4X4 extended cab with 208K for $2600. Sharp truck, has some rust but in NY almost everything does!
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
1725 RPM would be 70 MPH with double overdrive.
Red fuel on the highway could be some very expensive fuel if you ever get checked.
5000 dollars for the first offense here in WV.
Red fuel on the highway could be some very expensive fuel if you ever get checked.
5000 dollars for the first offense here in WV.
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Tuned
Joined: Oct 2004
Posts: 250
Likes: 6
From: new york
I checked back on this post and found that at 2000 rpm in double overdrive =78mph
With the E40D at 2000 rpm=59mph
Yea I know there is a chance of getting caught with red fuel, so I keep my truck empty no tool box or fuel tank in the bed, I got a couple or car seats in the back for the little ones, looks more like a grocery getter than a heavy duty pickup!!
With the E40D at 2000 rpm=59mph
Yea I know there is a chance of getting caught with red fuel, so I keep my truck empty no tool box or fuel tank in the bed, I got a couple or car seats in the back for the little ones, looks more like a grocery getter than a heavy duty pickup!!
Elder User
Joined: Apr 2006
Posts: 894
Likes: 0
From: South Dakota
I drive a 1991 Ford F250 7.3L with a ZF5 transmission, yes it is 2wd and 4.10 gearing. I get around 15 mpg driving at 2000 rpm going 59 mph (no load). I would like to even see that mileage you are getting. I would like to know, how would it shift in that ZF5? and how much modification would I have to do to put it in?
Hotshot
Joined: Feb 2004
Posts: 11,697
Likes: 3
From: Marengo, Iowa
The gear vendors can be set up to shift automatic or manually. Basically, you would just activate it after having shifted into 5th gear usually on the manual transmissions. You can also shift between the gears, say you have a heavy load, you would shift into the regular gear, then shift the overdrive, then out of the overdrive into the next gear, then the overdrive, then out of od and into the next and so on until you are in double overdrive. That is how the "underdrive" comes into it, as they basically consider second over to be 3rd under...
Last edited by fellro86; May 21, 2006 at 05:19 PM.
Elder User
Joined: Apr 2006
Posts: 894
Likes: 0
From: South Dakota
Well, I would go for that double overdrive...problem is that is $3000 brand new, sure there are ebay ones but you never know what they really are until you get it...I am also looking for a sidewinder turbo, needless to say I haven't found one yet lol...
Fleet Mechanic
Joined: Sep 2005
Posts: 1,509
Likes: 3
From: Ladner, British Columbia
RedGreen,
Going from 3 speed C6 to a 4 speed E4OD means going from a manually controlled tranny to an electronically controlled automatic tranny.
To do this from scratch with new parts would be way more than $3,000 just in parts.
You would need a donor truck that you could salvage all the ancillery parts, as always you get what you get.
The factory E4OD's had many quirks (many because of the first generation of electronic control) and from a reliability standpoint the C6 is a much better tranny.
That said an E4OD can be built to last if you are willing to spent the money.
A C6 to E4OD swap is not a inexpensive proposition, the Gear Vendor would be a better proposition both from a cost and technical standpoint.
Going from 3 speed C6 to a 4 speed E4OD means going from a manually controlled tranny to an electronically controlled automatic tranny.
To do this from scratch with new parts would be way more than $3,000 just in parts.
You would need a donor truck that you could salvage all the ancillery parts, as always you get what you get.
The factory E4OD's had many quirks (many because of the first generation of electronic control) and from a reliability standpoint the C6 is a much better tranny.
That said an E4OD can be built to last if you are willing to spent the money.
A C6 to E4OD swap is not a inexpensive proposition, the Gear Vendor would be a better proposition both from a cost and technical standpoint.
