bought a '96 cummins a couple months ago and it has a rambrake and us gears splitter.

phx24valve · 11-25-2010, 02:09 PM

ok so i bought a '96 cummins a couple months ago but hadn't had much time to mess with it due to a family emergency out of state. i got back the other day and started messing with it. it has a "Rambrake by jacob" exhaust brake on it, and in the cab is a "us gears" box with hi/lo. none of these worked... so i looked through the wiring a bit and found some issues, i got the us gears unit to light up however it won't switch from "hi" to "lo".

my question is, is this stuff worth investing a lot of time in to? all my trailers have brakes on them, and i don't tow really big loads. (maybe a 10k lb piece of machinery at most...usually cars).

if it wouldn't be beneficial for me to have these around, what would they be worth to sell? and what would i need for the transmission as the overdrive unit appears quite large... (basically would it be worth my time to sell them or should i just leave them)

also what is the average cummins 12 valve boosting? mine was boosting about 23lb....after i messed with this wiring now i'm hitting 27lb???? only thing i could figure was maybe the exhaust brake was partially closed and now it's opened?

Thanks

phx24valve · 11-27-2010, 08:59 PM

anyone?? any thoughts?

***Motorboat*** · 11-28-2010, 09:51 AM

You have two very valuable and useful options that anyone who tows heavy would find desirable. Your problem would be what to do after you remove them for the sale as each requires modifications or replacement parts for thier install.

I would get them working and use them occasionally just to keep them operational.

MX26 · 11-28-2010, 10:51 AM

Fix 'em, use 'em. That gear splitter is very nice!

phx24valve · 11-28-2010, 01:12 PM

i've tried to fix em, the unit lights up...but you push the button to switch the gear from the high indicator to low...and the high light turns off like it's switching then just goes back to high. and the exhaust brake doesn't kick in (appears to be wired in with the splitter, maybe it needs to be in low gear?)

i really don't want these things, but the splitter appeared to have replaced a large portion of the original transmission, and the exhaust brake appears to have replaced part of the exhaust.

MX26 · 11-28-2010, 01:19 PM

I don't know much about the workings of either, as I've never had the need or desire to run either, but... If they're already on the truck, they are both very expensive and handy mods that would be a towing trucks best friend.

You might want to get in contact with the splitter company. There aren't a whole lot of people on here running those units.

phx24valve · 11-28-2010, 01:22 PM

they don't appear to support the unit or even want to admit it exists.

justadonor · 11-28-2010, 01:23 PM

i'd be willing to bet that overdrive unit is a precursor to the gear vendor O/D unit, you might get in contact with them and get ahold of a wiring diagram or something to help you troubleshoot

phx24valve · 11-28-2010, 01:32 PM

heres a couple pics:

splitter:

exhaust brake:

***Motorboat*** · 11-28-2010, 01:43 PM

US Gear no longer makes the underdrive unit. The C brake is most likely stuck open. Too bad we aren't closer to each other.

phx24valve · 11-28-2010, 01:51 PM

did the gear splitter replace the whole half of the transmission or is it just the tailshaft it replaced (and a shortened driveshaft?)

***Motorboat*** · 11-28-2010, 02:07 PM

Yes...............tailshaft