Dual one range

[adam g]

I was getting my 84 f-350 up and running today. It has been a parts donor for my others but a friend wants to trade it. It has a gearbox behind the tranny. Its not a gearvenders I have one on my 89. I guess what I want to know is this dual one range an over/underdrive or just an underdrive. I bought the truck from a construction company for the hypermax turbo off it and they never used this gear box. I'm getting ready to set down and figure the numbers out for the trade. If he wants a staight trade I want his old motor my tranny and gearbox.

 

[Diesel JD]

What kind of gear box is it? Pictures? If its a 2 range gear box most likely it's either under/direct or over/direct. The Doug Nash boxes were either over/direct or Under/Direct. The under drives are marked on the input gear, Jim at US Gear can give you that info if it is a US Gear or Doug Nash box. If it is not this box and not a GV is it a Ranger or Advance Adapters box? Those mounted between the main box and the engine and were manually shifted, lastly it could be a very old Spicer brown lipe 5531 which was a 27% overdrive/direct one way and could be simply turned around and made into an underdrive/direct box. That is probably best case scenario but least likely. The U/D only Doug Nash/ US Gear boxes are pretty useless, I just sold one on ebay for very little. A lot less than I paid for it.

 

[dyoung14]

did they ever make a under/direct/overdrive box?

 

[Diesel JD]

Yes that is what the 3 speed Spicer brownie boxes are like the 5831 that RLDSL has. A local Junkyard might have 2 I will have to look, but my motivation is low at the moment since I just don't have the money to buy one. Try and find GM 6066 Guy's website, should pop up if you google "Spicer 5831" they are non synchronized boxes so you better be able to double clutch or float gears, I have only heard of them installed on a 2wd model, I don't know if it's possible on a 4X4 or not.

 

[smokin69]

You can put one on a 4x4, just not for use in 4 wheel drive.

 

[Diesel JD]

Ah I see, would it mount between the Xfer case and the tranny or after the xfer case? Too bad you can't use it in 4WD some of those ultra low range gears together with 4WD would be sweet.

 

[adam g]

I will take pictures Monday. I can't go to the shop today.

 

[Diesel JD]

Ok this should be interesting, my guess is that it's a Doug Nash box, either o/d or under plus direct.

 

[smokin69]

Ah I see, would it mount between the Xfer case and the tranny or after the xfer case? Too bad you can't use it in 4WD some of those ultra low range gears together with 4WD would be sweet.

The three speed brownies mount after the t-case, there a divorced case, like an oldschool NP205, and mount in the driveshaft, if you have a two peice driveshaft it would be pretty simple, just mount it where the carrier bearing was and shorten both shafts.

 

[FordGuy100]

You can put one on a 4x4, just not for use in 4 wheel drive.

Well unless you got yourself a 2wd tranny, then ran the brownie box, then that into a divorced transfer case. I just think that it could only be dont on a extended cab or longer model, the driveshaft angle would be to steep on a regular cab.

 

[smokin69]

I would be worried about the driveshaft hitting the brownie during articulation, there pretty big

 

[FordGuy100]

I would be worried about the driveshaft hitting the brownie during articulation, there pretty big

Thats what I was thinking too, it might be just to long to do. I can see U joints going out fast to.

 

[smokin69]

With the long driveshaft in the front it would seem like lots of vibration, the reason the long rear shafts are two peice units. BTW, your truck looks like a more ****, clean twin to mine lol

 

[RLDSL]

With the long driveshaft in the front it would seem like lots of vibration, the reason the long rear shafts are two peice units. BTW, your truck looks like a more ****, clean twin to mine lol

The long front shaft not a problem if it's built right. The guy who built mine made that sucker stout enough for a semi truck . It's heavy as heck, but runs smooth. The way mine is mounted the front shaft is about max allowable length for a single and the rear is about the minimum that most shops can make ( I've seen one after I had mine made up that can make a 9' but most call 18" min. )
I don't have any more vibrations after getting teh box alligend properly, but I still want to put some angle shims on the rear axle to put just a hair more angle on the pinion end ujoint to make them more even

 

[smokin69]

I was talking about the front driveshaft for a 4x4, with a 2wd trans, a brownie, and then a divorced case, thats a long distance to cover with a single shaft that is expected to articulate up and down side to side with front axle.