Opinions on different 4x4 overdrive options

[70f350]

I have seen this question over and over but have never seen conclusive answers. So...

In a f-250 4x4 with a married new process 205 transfer case what would be the best overdrive option? Has anybody here ever done something like this? Also, what are the options and opinions for the divorced TC applications?
I have heard about the ranger overdrives and personally have seen good things with these.
ZF 5 speed any good? Would this be a better choice than the ranger? NV-4500 5 speed seems to be the choice but is on the expensive side?

Help us o-wise-ones.

[averagef250]

I have had ZF close ratio, wide ratio, M5R2 and NV4500's in my highboys with carb big blocks, EFI big blocks and turbodiesels.

My favorite is the M5R2 followed by the close ratio S5-47 ZF. The M5R2 wins for me because it consistantly beats the ZF in respect to mileage. It's a smaller tranny which I loosely figure equates to less parasitic loss. I choose the S5-47 over the S5-42 ZF because over the long term the 47 shifts better longer with it's updated shift detent design that's the same as used in the S6-650 six speeds. I dislike NV4500's. They are very expensive, most are 100% shot these days, they are maintenance intensive require frequent $80 oil changes with oil you cannot just buy off the shelf anywhere and they will instantaneously delaminate synchro lining if you run anything else.

IMHO splitters suck in light trucks. Why would you want one? I know guys that have them and love them, but they love them for the novelty of having an extra lever or button in the cab. Functionally, the ranger scores a zero in my book. If it's your last option and someone gives it to you maybe it's worth the hassle of installing it, if you have to pay real green money for one it's bad investment. Known several guys who've bought trucks with rangers installed and grew to hate them. They are finicky, they are crude.

If you like Rube Goldbreg type stuff you'll love a Ranger splitter. If you visit reality now and then the Ranger may not be for you.

The biggest question I have for you is why do you need an overdrive? I can tell you from extensive personal experience if it's for fuel mileage with a carb engine you will not see it. I gained a better mileage increase on a properly tuned nicely built 4500 RPM 390 by installing a good $120 thermostatic clutch fan than I saw from investing countless hours and thousands into an NV4500.

I found out the hard way a carb engine simply doesn't make the part throttle grunt down low needed to cruise at 70 below 2000 RPM.

Overdrive is for modern EFI and turbodiesels. Any other application has zero use for it.

[70f350]

If you like Rube Goldbreg type stuff you'll love a Ranger splitter. If you visit reality now and then the Ranger may not be for you.

I laughed my a$$ off when I read this part. I couldn't have said it better.
For those of you who don't know who Rube Goldberg is I found this... http://www.rubegoldberg.com/

Anyway...
Average, Thanks once again for your input.

The plan is to go with an EFI 300 or EFI small block, I haven't made up my mind 100% yet. Iv'e driven both in newer trucks and I'm leaning towards the 300.
I would like to be able to tow a decent amount and be able to get decent milage. I realize I can't have 100% of both but would like to be somewhere in the middle.

Will the M5R2 and the ZF's bolt up to a NP 205 transfer case or do you need an adapter? Any recommendations on where to find parts, adapters, etc?

Thanks.

[70f350]

I have searched for this kind of topic many times in different forums and haven't gotten that many results. I just did a quick search this morning and found a slew of info WTH! At the same time because I finally found what I was looking for.

Here are some to check out if you're interested.
http://www.fordification.com/forum/view ... &view=next
http://www.fordification.com/forum/view ... &view=next
http://www.fordification.com/forum/view ... &view=next
http://www.fordification.com/forum/view ... &view=next
http://www.fordification.com/forum/view ... &view=next
http://www.motivegear.com/tech_info/tra ... guide.html

Any more opinions would be great.

[mlheppl]

I think the S5-47 would be a good choice for my highboy. I don't have a tach but I know the motor is winding up pretty tight at 75mph (interstate speed here in NM). Heck it's sounds like it's revving pretty high at 65mph for that matter. Right now the truck is stripped down to the frame, so I'm trying to decide if this might be an option I want to persue myself.

I'm running a 400 motor. I've got a married dana 205 I could swap in. I'm running 4.10's for gears and 33" tires. Fifth gear on the ZF is a .75 ratio, so that would make the equivalent of 3.00 gears roughly when in 5th. It seems to me that I should be able to maintain speed/rpm's in 5th gear with a "final" of 3.00 with 33 inch tires, but maybe I'm wrong.

[averagef250]

I think the S5-47 would be a good choice for my highboy. I don't have a tach but I know the motor is winding up pretty tight at 75mph (interstate speed here in NM). Heck it's sounds like it's revving pretty high at 65mph for that matter. Right now the truck is stripped down to the frame, so I'm trying to decide if this might be an option I want to persue myself.

I'm running a 400 motor. I've got a married dana 205 I could swap in. I'm running 4.10's for gears and 33" tires. Fifth gear on the ZF is a .75 ratio, so that would make the equivalent of 3.00 gears roughly when in 5th. It seems to me that I should be able to maintain speed/rpm's in 5th gear with a "final" of 3.00 with 33 inch tires, but maybe I'm wrong.

I think you'll be disappointed. You will be able to slip it into overdrive at 65 MPH and will most likely have to downshift into 4th at the slightest hill. You will not pull 5th in 55 unless you're going downhill.

You're turning around 3100 RPM at 75. With a .75 OD you will see 2350. Those numbers aren't great to me. I think you'd have a better result with a 400 if you just switched in some 3.73 gears. That'd be around 2800 @ 75, much better suited to an old carb motor.