Heard about someone setting up to run a dropbox behind an allison. Is this possible? How so?
C-ya
C-ya
Dropbox behind Allison
- Thread starter SmokeShow
- Start date
I'm sure Fabco or Cotta could make something or even may have something that would work, but if your just looking for something to run a hyd pump or similar, there is a place to bolt a PTO on-but I'm sure you already knew that so what do you have up your sleeve Mitch?
As much as I wish it were, this ain't me. For now, I suppose it's just a rumor for a pull truck.
I seem to recall back in my thread about converting a 2wd alli to 4wd, Mike said the speed sensor needed to be post transfer case... even if using a 2wd trans. with divorced xcase. So that's kinda what I'm wondering. Where the hell would you put a speed sensor on the output shaft of a dropbox? Or did I understand something wrong back then.
I need to go re-read that thread because I can't remember the reasoning behind why the sensor needs to be post xcase.
C-ya
I seem to recall back in my thread about converting a 2wd alli to 4wd, Mike said the speed sensor needed to be post transfer case... even if using a 2wd trans. with divorced xcase. So that's kinda what I'm wondering. Where the hell would you put a speed sensor on the output shaft of a dropbox? Or did I understand something wrong back then.
I need to go re-read that thread because I can't remember the reasoning behind why the sensor needs to be post xcase.
C-ya
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IIRC Kyle at Crank it up had a drop box behind his. But switched to a 205 because of OEM only rules.
now we all need to pool our money together and buy that kickass truck Watson started but now has posted forsale on CompD. 
I was REALLY looking forward to seeing what he could get out od the Dmax. Evidently not enough up to his standards.
C-ya
I was REALLY looking forward to seeing what he could get out od the Dmax. Evidently not enough up to his standards. C-ya
So I went back and read through my old 2wd to 4wd thread and looks there's a way to make it work (at least "on paper") whether the SS is on the ouput of the alli or on the output of the xcase.
It would sure be crazy trying to utilize the quick change gears in a dropbox if you had to redo the tuning everytime so the computers understood. For this particualr setup (dropbox) I think it might be better to have a 2wd trans that only knows one way of shifting and divorce mount the dropbox. That way it will always shift at a given RPM and throttle position without having to reprogram the TCM to know the truck is in 4LO and at whatever gear reduction the particular flavor of gears are in the dropbox at that time.
Hmm, so this is looking to at least be capable of being true, no?
It would sure be crazy trying to utilize the quick change gears in a dropbox if you had to redo the tuning everytime so the computers understood. For this particualr setup (dropbox) I think it might be better to have a 2wd trans that only knows one way of shifting and divorce mount the dropbox. That way it will always shift at a given RPM and throttle position without having to reprogram the TCM to know the truck is in 4LO and at whatever gear reduction the particular flavor of gears are in the dropbox at that time.
Hmm, so this is looking to at least be capable of being true, no?
Transfer cases. Like a Profab or SCS. They are what's found in the mod and unlimited driveline pulling trucks.
As stated it's a transfer case used in many Mod pullers. I would ASSume it received it's name due to the outputs being much lower than than the input (dropped) so as to keep driveline angles much more managable. The higher the angle on the driveshaft, the less power is transmitted. A Zero degree is best for power, but for longevity a 1-2 degree is preferred as the slight angle contributes to roller bearing movement and keeps the cap from being hammered in the same spot by the same rollers time and time again (like an impact gun).
On a conventional t-case the rear output is inline with the front input. With a drop box that is not the case.
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and I'm told, in the event that a person is NOT running centered pumpkins in either the front or rear (like is conventional on mod pickups) that you can clock the dropbox halfway between the front and rear and be alright. That might give you just a little more driveline angle than 1-2* but they could still be kept relatively flat and work appropriately. I thought that was interesting.
C-ya
C-ya
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maybe it's a shop truck? or someone holding tight to the roots? sponsorship?
I don't know really why though.
I don't know really why though.
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There are a couple different ways to do the speed sensor thing with a dropbox. Almost every KW truck we have at work is set up this way. I will get some pics and post them up of the different config. you can do.
Basically, a mag pickup (speed sensor) and some sort of round wheel with holes evenly spaced drilled into it, or one similar to your reluctor wheel on the crank in design would work. You would basically need a companion flange at the output from the dropbox and bolt the tone wheel (reluctor wheel) to the flange.
Basically, a mag pickup (speed sensor) and some sort of round wheel with holes evenly spaced drilled into it, or one similar to your reluctor wheel on the crank in design would work. You would basically need a companion flange at the output from the dropbox and bolt the tone wheel (reluctor wheel) to the flange.
Buy the Suncoast billet extension housing. We engineered a hole into it for this purpose. You can put the speed sensor ahead of the t-case so the TCM doesn't care about the gear reduction.
Plus if you have the cash for the dropbox you've got the cash for the extension housing. And I wouldn't want to hang a dropbox on a stock extension housing because of the weight.
X2. You can also mount it back farther and run a short driveline to it.
Chances are any dropbox you run is going to have to have companion flanges to be able to bolt up to it so likely you will need to do this anyhow to make it work.
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Here are some pictures of the divorced transfercase setups on our KW 6x6 tractors. It should give you an idea on speed sensor set-up.
The only difference between it and a dropbox is a dropbox allows you to complete disengage the outputs to drivelines so you can use your transmission/dropbox arrangement to run a hydraulic pump or an auxilary drive. A transfercase always has an output engaged unless it is in neutral in which case nothing on the output side will turn.
The only difference between it and a dropbox is a dropbox allows you to complete disengage the outputs to drivelines so you can use your transmission/dropbox arrangement to run a hydraulic pump or an auxilary drive. A transfercase always has an output engaged unless it is in neutral in which case nothing on the output side will turn.
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