Timex dual-transmission project (NP435/NP435/NP208) [UPDATE 1]

[Sycho15]

I deposited my income-tax return yesterday, and paid for my transmissions and transfer-case today. Due to rain they will be pulled later this week.

Source vehicles:
'85 F250- 300 I6, 4-speed (NP435), 4x4 (NP208?)
'86 F250- 300 I6, 4-speed (NP435), 4x2

Novak's Knowledge Base- The NP435

The transfer-case has a slip-yoke rear output. I have two options here: Swap the input shaft from the Ford 'case into a Jeep 'case, or swap the fixed-yoke output from a Jeep 'case onto the Ford 'case. Since I have a spare-parts Jeep NP208 lying around (the "Bottomless Transfer-case") I plan on putting a Jeep output onto the Ford 'case.

As these are unkown junkyard parts out of old worn-out and beat-up work trucks, I will be rebuilding everything.
Drivetrain.com NP435 Rebuild Kits
Drivetrain.com NP208 Rebuild Kits

My friend and co-worker is a CNC machinist by day, and will be doing the machining required. I'm expecting that he will need to do the following:
Cut down input shaft of 4x4 transmission. The input shaft is rather long and the splined section is smaller-diameter than the non-splined section.
Spline input shaft of 4x4 transmission. New splines will need to be cut into the larger-diameter section of the remaining input shaft.
Create output-to-input sleeve. A coupler with internal splines to accept the output shaft of the 2wd transmission and the input shaft of the 4x4 transmission.
Create adapter to join the 2wd transmission to the 4x4 transmission. Sounds simple enough, doesn't it....

Budget:
Income-tax Return: +$1000
Expected sale price of current drivetrain: +$300
Total: +$1,300

Cost thus far:
NP435s: -$200 x2 = -$400
NP208: -$150
NP435 rebuild kits: -$155.65 x2 = -$311.30
NP208 rebuild kit: -$172.82
Total: -$1.034.12

Remaining: +$265.88

Not accounted for: Driveshaft modifications. The rear driveshaft will have to be shortened, and a two-piece front driveshaft built. I have a few driveshafts lying around so costs should be minimal.

[ April 19, 2005, 08:39 AM: Message edited by: Sycho15 ]

[bigun]

Sounds like a plan please take lots of pics

[deuce228]

Never adds up to what you expect with a jeep..........good luck tho

[FSJeeper]

I have thought about doing something like this for years. You chose well on the NP435. NP208 is a great tcase also. You probably needed nothing but synchro's for the NP435's, they wear very well and I have never seen a broken one.

Take lots of PICS!

[yeep74]

Cool

Lets see lots of pics as I want to run a similar setup in my J-10.

Good Luck and best wishes
Brandon

[scotty]

ya,lots of pics. i cant wait to hear how it works out for ya [img]smile.gif[/img]

[Sycho15]

I picked up the transmissions and transfer-case today. They cleaned them after they pulled them, so I could better see what I got. Unfortunately the 2WD trans is a T18 and not an NP435. I couldn't tell them apart when they were in the trucks because all I could see was a big ball of grease with a PTO on the passenger side and a squiggly shifter sticking up in the cab. Sitting side-by-side I can tell that the shifters are shaped a little different and the way they go into the transmissions is also different. That information will help when I go back and have them pull me another $200 trans to replace the T18. Hopefully I can sell it to a baby Jeeper looking to convert it for use in a CJ or something....

At least the t'case was the NP208 and not the BW unit. I'll order the rebuild kit for it and get to work rebuilding it and converting it to a fixed-yoke rear output with parts from the "bottomless transfer-case" that came with Timex.

[JeepsAndGuns]

looks good. Sent ya a email.

[Amc71601]

I'm not too far away for a WOT if you need a hand when you get ready.

[Sycho15]

J&G- I'm not seeing any e-mail or PMs... where did you send it?

Amc71601- thanks a ton, I might need some help when it comes to actually installing everything. Most likely I won't do the install until the entire drivetrain has been built- including a stroked 4.0 to replace the clapped out 258 that I hope will make it to the ECI and back...

[JeepsAndGuns]

Sent the email to sycho15@hotmail.com Must not have went through, I set ya a pm this time.

[worn4wd]

just some food for thought....6.33x6.33=40.07 that is the combined gear reduction, times 200 ft.lbs of tourque [stroked I6] 8014ft.lbs of tourque.the people at klune-v only recomend,an atlas, or a 205 behind there box because the case of the 208will not stand up to the increase in tourque.hate to see you inwest alot of time in something destind to break. 205 cases were used by everybody ,and in a variety of configurations.they can also be twin sticked to allow better offroad capability.good luck let me know were i can get my 435 435 adapter so i can see what it snaps off!

[Cecil14]

Actually the torque from a stroker would end up closer to 300 lbs., even at factory bore. Been there done that. Not that that helps the situation at all. I think if you're careful with it you'll be able to keep a 208 alive for a while. The 208 is a pretty stout case aside from the fact that it's aluminum.

aa

[Sycho15]

Also- first gear is 6.68, not 6.33.
6.68 x 6.68 = 44.62
6.68 x 6.68 x 2.72 (axle gearing) = 121.37
6.68 x 6.68 x 2.62 (low-range) x 2.72 (axle gearing) = 316.78

I'm not planning on hard-core 4-wheeling this Jeep. It'll only run 33" tires, and I want to keep the sheetmetal straight. It'll see some trails, but more towing and daily-driving than anything. I've got a 5500# boat on a 1000# trailer to move around on occasion, and I'm sure my YJ and it's trailer weigh in the same ballpark.

[orangecherokee]

so you mean this is not for wheeling but for towing?

why do you need that much gear for towing? i would have just messed with the cogs and run a steeper gear set but that's just me.

[Sycho15]

By cogs I assume you mean R&P? Let's just say that "I want it all". Right now, with 31s, I can cruise down the interstate going 70mph at 2071rpms. I usually go 80-90mph and that puts the engine right where it likes to be. By 2959rpms I'm going 100mph. The current setup works wonders on the highway.

The pinion for a 1/2-ton 2.72 gear set is comparatively huge. I'm not really worried about breaking it, and if I do it'll be easy enough to get a replacement since people pretty much give them away.

The lower gearing will let me pull my sailboat in and out of boat ramps if I feel like dunking my trailer. You have to remember- I've got a clapped-out 258 in this rig, and while it's basically a good engine, it's not a monster. I'll be replacing it with a carbed 4.7L stroker which will be a huge improvement, but it's still no 401 (YJ gets the 401 [img]smile.gif[/img] ) I don't have to use 300+ ratio to pull the boat out. I'm sure 1st/3rd or 1st/2nd will be enough. The uber-low gearing is just for control, and so I can practically put the truck in park with the engine on and in gear on a steep hill. I don't trust E-Brakes.

Low gearing will also let me do mild/moderate trails like Tellico's 4&5. I'll have a ton of control and shouldn't need to be getting on the throttle to go places. I have a EZ-locker to go in the front axle as soon as I get a hardened cross-shaft for it. The rear might just get divided E-brakes.

After the engine,trans,trans,t'case rebuild I'll start on an AMC20HD full-floating conversion that will use the stock D44 front axle spindle and parts. Will have to get custom shafts but that shouldn't be a big deal. Sure, it would be easier to find a J20 rear axle, but it won't have the gears I like, would be heavier, and would decrease my ground clearance with those little 33s. The 1/2-ton axles are just fine but I want them to be very reliable.

Eventually I'll mess with the suspension. I'll make my own setup to give me a cush on-road ride and something that can take bajaing in the Ocala National Forest without jarring loose my fillings.

Hardcore 'wheeling will be left to the Wrangler. YJ sheetmetal is plentiful and cheap and I don't give a care about bashing it up. The YJ will have an entire SJ drivetrain by the time I'm done... I have all the parts now.

[worn4wd]

i only have 1 np 435 in my wagon [im ok with it] and a 208 case finaly got to pull it out of the garage.......ordered 35 spline axles. please let us know when you get yours going.good luck.

[Sycho15]

I'm picking up the 2nd NP435 (the 2wd one) on my way back from the ECI in June. That is, if the truck makes it to the ECI without catastrophic engine failure.

I've also changed my mind on rebuilding them straight away. I'm going to pop the tops and check out the innards, and if everything looks good I'll just finish cleaning them off and send them to the machine shop.

[Stuka]

Hope your going to have at least 1350 ujoints, maybe even bigger. They are going to see a LOT of stress with having such high final drive gearing.

[bigun]

I know I am delving in the past but how far along did you get with this idea?

[ January 28, 2006, 08:04 PM: Message edited by: bigun ]