Has anyone ever tried installing a transfer case backwards, can it work as a overdrive. My problem is my F-350 c-6 and 4.10 is way low for normal driveing but is great with the 5th wheel. If I could do this at the switch of a lever I could have both, no 4-wheel of coarse. Any thoughts.

MT

 

If you used a remote mounted T-case, yes you could put in backwards.
However, a NP205 has about a 2/1 reduction in the normal position. Turn it around, and your 4.10 becomes approx a 2.05/1. I don't have any idea about drive shaft angles and oiling, running backwards) Hope this helps a little. Elliott

 

Thanks Elliot, NP205 would be found in which vehicles?
MT

 

>Thanks Elliot, NP205 would be found in which vehicles?
>MT

NP-205's can be found in; 69-73 Blazers and Jimmys with automatics, 70-73 GMC pickups and suburbans, 75-79 Chevys and GMCs with manual trannies, 81-87 Chevy and GMC K3500 pickups, 69-74 Power Wagons, 80-84 Dodge Power Wagon W200s, W250 crew cabs nad W300s, and of course 76-79 f150s, 250s and so on. You can find them almost anywhere. The only thing to watch out for is that they were made with both right and left hand outputs as well as divorced versions.

mike

 

Thanks Mike, Whats a devorced version? Any difference in driveshaft conections, which would be best for the 460 1985 C-6?
MT

 

[updated:LAST EDITED ON 19-Jun-02 AT 00:27 AM (EST)]>Thanks Mike, Whats a devorced version? Any difference in
>driveshaft conections, which would be best for the 460 1985
>C-6?
>MT

With the NP 205 there are two styles. The first one which is most common is where the tranny and transfer case are bolted together. The other version is the divorsed. The tranny and transfer case are seperate and are connected by a short drive shaft. I think its around 22" or something. Anyways for a 1985 it would be easier to go with the first version, bolted to the tranny. This is if you are using it like a normal transfer case, for 4 wheel drive. However if you are planing to use this as a overdrive unit or underdrive divorced would be the way to go. Personally i wouldn't go this route for a overdrive. The 205 is a gear driven transfer case, and can not be shifted on the fly. If i was to go about doing this, i would get a NP 203. Its similar to a 205, but its tailhousing is made of aluminum which is a little weaker, but that doesnt really matter, and its chain driven which can be shifted on the fly. The low range is 2:1 compaired to a 205s 1.96:1. Another thing is i would get a solenoid or a little air or hydralic cylinder to do the shifting, theres nothing wrong with a stick, but it would be nice to push a button. Well I'm not really sure how this would work, with all the driveine and frame mods or how the transfer case would work but its sounds like something to try.

mike

 

WOW, COOL IDEA!!!

So you'd mount it backwards and the input becomes the output and so on...

The shift on the fly would be a great way to go. I've also seen where the TC was cut so that you don't use the 4x4 part, just the straight thru part.

I was thinking of the double TC trick for this but that would require gear changes both front and rear, now I can do the same thing without out the expense of the gear change.

Good thinking!!!

 

Thanks again Mike. I would not need the shift on the fly use with a 2 to 1 overdrive, but the result of dropping from 4000 rpm at 65mph to 2000 rpm would be great! I would have no use for the four wheel drive output, is that not the chain driven part and could I not disconnect that part and gut it?

MT

 

Not to be the guy that rains on this parade, but...

Wouldn't a piece of machinery that is designed to travel more in one direction than the other fail due to over use in that wrong direction. The engineers designed these things for a specific direction of travel. Thrust absorbing devices would need to be modified...

Cool idea, but not something I'm willing to spend a couple of grand on and a month on. Welcome to reality.

-Kerry

 

Kerry: These are questions I'm trying to get answers for. If the gearing is of the right type would it wear proper? Has anyone done it? Thanks for raising the point. Mike has a good idea with the solenoid.

 

Instead of reverse installing the case, maybe a different type or set of gears in the case would better suit an overdrive. The 208 uses a reduction planetary set for low range in the front of the case. I don't think a planetary set would make a good high speed OD. You have a lot of frictional drag in that design.

Just some more food for thought.

-Kerry

 

 

Maybe it's a little late to be resurrecting this topic, but here's a link: [link:www.exaxt.ca/EXAXT_Miscellaneous.htm | www.exaxt.ca/EXAXT_Miscellaneous.htm]

They sell kits to install a 205 backwards in a Chebrolait. Costs megabucks, though.

 

There are two good choices, #1, get a US Gear overdrive or find a small aux trans (spicer 6041) which would give you 2.41,1.24,1.1 & .80 Note; My 5th wheel & cutaway weight in at 20,500 lbs. I pull with a 89 HD E350, 460 FI, E4OD, 4.10 rear end, w/215/85X16 tires. I'm tac-ing 3G at 65. If I try OD, I have no vacumn reading. Between 2800 to 3000, I run about 10 inchs on level ground. My problen is running about 60 to 62, I can't down shift untill about 45 mph. I need the US Gear under drive unit so I can split the factory gearing. Ideally, I need a Clark 282 that has a 1.17 4th gear. Hope this helps. Elliott