Aftermarket overdrive/gear splitter questions

[LonesomeSTX]

I want to install an aftermarket over drive in my truck. First question is, is it an aftermarket over drive or a gear splitter? I have heard them called different things. Also, which one do you all recommend? The only two I know of are from Gear Venders and US Gear. I am leaning towards the Gear Venders model.

http://www.gearvendors.com/f2wd4s.html

http://www.usgear.com/dual_range.htm

Are there any other options out there I should consider? What should I know before entering into such an expense?

 

[Will]

It's the same thing. All it is is a gearbox that bolts behind the transmission. It provides overdrive in every gear so you can shift up in half steps. It narrows the rpm range your engine has to operate in allowing you to use the thickest portion of you torque curve. It makes a big difference if you are using most of your engine power to tow something. Most of the time, I leave mine in auto and it shifts into 3-over on its own. But going up a big hill with a lot of weight and the exhaust temperature is getting up around 1,000F it's nice to click it down a half gear to cool the exhaust without loosing speed.

One big problem towing things that use all of your engine power is that you sometimes don't have a gear to go into. Like you hit a hill at 60mph at 2,000rpm and you don't have the torque to keep going 60 so you start slowing, but you can't downshift until you get to maybe 35 because the next lower gear will overspeed the engine. You only see this problem with really heavy loads so if you don't encounter this you are better off getting a tranny with an overdrive like an AOD. The Gearvendors is expensive as hell for just an overdrive. You can get a well built AOD for half the proce, and will have a lockup converter as well. A lockup converter locks the converter so it doesn't slip giving you a lcoked up geartrain like a manual tranny has with the only wasted energy being used to run the hydraulic pump keeping the clutches engaged.

 

[fordtrucknut77]

I saw a unit of this type listed on broncograveyard that mounts in front of the trans but its only rated to hold like 550 pounds of torque

I have seriously been looking into getting the gear vendors unit to go behind my np435 just because of what was mentioned above

 

[LonesomeSTX]

Thanks Will, that is good information.

I guess I should have mentioned what it will be going in. 1 1995 F350 with a 7.3 and a E4OD.

I will have to check out the one from BGY, that one may work in my Ranger biuld.

 

[Will]

Good. I was wondering why you were interested in a splitter for a Ranger with a V8.

I'm not sure if these specs are exactly right, but it seems like a stock '95 Powerstroke is pretty similar to my engine with the torque and torque peak about the same. I modified my spreadsheet (attached) with your gear ratios--you can change the gear ratio and shift points as I left mine in there.

You can see it really focuses the engine around the torque peak. Thing is, if it isn't loaded with like 10,000# then it doesn't spend enough time in a gear to use it. The only time I was really glad to have it was in Pittsburgh at a traffic light at the bottom of this long steep hill in a lot of traffic with my newly purchased JD crawler on the trailer. It was nice to have a bunch of gears then. But normally the diesel has enough torque that it doesn't need that many because I don't have a 14,000# fiver. I get up to 9,000# probably and then it's starting to be useful, but not for my 7,000# B2/trailer that is more typical of what I pull.

 

[LonesomeSTX]

Very cool man, thanks.