So my power's been off for a while thanks to the lovely hurricane that did absolutely nothing cool or interesting, but seemed to knock down every power line for 200 miles, BUT, I had lots of time to think, and not many other options.... and one thing I thought of, is whether it would be possible to use a second T-case, as a doubler? An overdrive? The main idea is to essentially (and probably literally) turn an NP205 around backwards, and put it behind my first one. On paper, this would give me a 1.96:1 ratio, not exactly something I could just jump into at speed like a real O/D, but if I could halve my highway RPM's, that would be great! And I could change from a 3.50 rear gear (perfect for me and my current setup) to like a 3.93 or 4.11 to retain torque on the highway, if I even decide I need to.

I would have to get my drive shaft shortened, and make a second set of T-case mounts, but for the savings I could justify the shaft, and I could easily weld up the brackets.

I'm having a little trouble picturing it, but I believe it would be flat side to flat side, and double output sides facing front and back, away from eachother. A shaft of some type could easily be fabricated for in between them, and the second rear output could even be used for a PTO!

Is there any reason this just wooouldn't work? Like can the gears only spin in one direction?

Has anyone ever done this before? I've never heard of it.

Let me know, AleX

 

I don't think that would work. The 205 already has a gear ratio of 1.96:1 in 4 lo. One would cancel the other out. Unless you run them both in 4 lo. Then you would have close to a 4:1 lo range. Which could be easier accomplished with a 203/205 doubler. But I don't think you could get an O/D out of it.

 

Doubler? YES! Use the front half of the NP203 in front of an NP205. I recall it needs an adapter plate. Google it for info. Besides a shorter driveshaft, the driveshaft angle will need to be corrected since the U-joints are closer to each other. Easier to do on a long bed than a shortbed.

Overdrive? Interesting thought..... you HAVE had lots of time to think.

Gears? Yeah. They've gotta be straight cut if you want to turn it around. Otherwise, the force will be applied on the downhill side of the gear's teeth and it wouldn't last very long.

 

Brenner, yes, if I ran them both in low, but that isn't the point. My goal would be to have the capability to run in normal 2wd, 4wd, and 4wd low, AND to run in essentially, 2wd double. I would do this by using my front T case the same as always for all 4wd, running both cases in 2wd for normal around town driving (straight through, no reduction), but then switching the reversed one into 4 low for long highway trips, and therefore having more or less a 2:1 final output, compared to stock.

And HIO, ahhhh, good to know, I was thinking there might be an issue reversing the gears, thanks for letting me know! And OK, I'll look into the 203 thing, not sure what you mean, but I'll be able to figure it out.

Back to the drawing board on this one I guess, but much better now than when I'd gotten any amount paaast the drawing board. Love the fast answers I can get anytime of day or night, it's the perfect way to brainstorm stuff. Thanks for the help! AleX

 

If you run the front case in 2 hi and the rear in 4 lo won't that give you an underdrive? Raising your highway rpm. I like you're thinking on this.

 

Well if they were both facing forward that would be an underdrive, but that's the whole idea, reverse an underdrive, you get an overdrive. I'm saying like, run the output shaft of the normal 205, INTO the output shaft of the other one. Running a shaft into the side of the case that normally spins at essentially half speed when it's the output, means that whatever gets inputed into that is in a ratio of .5:1 to the output, and .5:1 scaled up to a real fraction, is 1:2. See?

Summary, 1:2 (stock) reversed = 2:1, a doubler!

 

I get what youre saying, but sadly i agree with HIO, the gears would push against eachother in the opposite way theyre designed either dramatically increasing internal wear, or causing catastrophic failure. This would however work if you stayed in reverse except everything else would wear faster / be weaker lol. Definately kudos for thinking outside the box.

The 203/205 doubler is basically the guts of both t-cases meshed together to create one beautiful piece. You can control the front and rear differentials independantly, for instance. You could have the front in 4lo and the rear in neutral. the rear in hi and the front in low kinda thing. If im not mistaken you also get lo lo range, basically 4:1 out of the t-case. Also known as twin sticks as it takes 2 t-case shifters to run the 1 unit once combined. I had the pieces but never got around to doing this for my ranger when i was doing the SAS. Can be done with a BW 1350 and 1354. Basically you split the cases, build a plate that allows both halves to bolt up to it, and machine the output and input shafts to be one shaft and done. Not sure what it takes to do with the NP cases but im open for the info, i have both layin around somewhere.

 

One other thing to look at with this equation. Most overdrives are just shy of 1:1. So if you double it to 2:1 like you're saying you would need somethin like 6.30 gears to not have a highway rpm of like 200 lol

 

Maybe he wants to cruise at 110MPH

I would just save up for a Ranger Torquesplitter myself. And twin stick the 205. Now you've got four shifters on the floorboards

 

Yes yes, the 205's are out, because of the backwards gears.

But Brenner, I know it would be very dramatic, that's why I said I couldn't engage while moving, but to go 70 mph with 3.50's and 31's right now, I'm right around 3000 RPM! So a backwards 205 would only cut that in half, to 1500. Take that down to 55 or 60, very common hiway speeds, and you do get out of the powerband, but the type of trips I'm talking about are like, hours long highway runs. I just wouldn't pass, or if I really needed to, or hit a really steep hill or something, I could downshift my C6 into 2nd on the fly.

 

I'm not gonna lie that woudve been an awesome idea haha. Look around for a gear vendors? Or jump to 33's with a taller gear.

 

A fella down on the 48-60 sections has done it, you might want to drop own and ask him some questions. Here's a link to a thread he posted in: https://www.ford-trucks.com/forums/1...overdrive.html

I would prefer the reversed 4spd transmission though, think about it, granny gear would turn into crazy overdrive! You could run 5 or 6-something rear gears and still cruise on the freeway!

Sam

 

I looked into the same thing, also getting a different gearset for my NP205 but I ended up with a Mitchell Overdrive. Keep us posted.

 

Hell yeah!

https://www.ford-trucks.com/forums/5...ed-w-3-od.html

Josh

 

WOW! That is bad ***.... I love the linked shifters. I guess he wouldn't need a second clutch then? If they both shift at the same moment?

And if he's running an entire tranny backwards...... that really gets me to wondering about whether the reversed angle gears would be an issue.

Does the 435 have straight cut gears?