NP 200 Straight Thru Conversion

This is meant as an information post to those thinking about this. I just finished putting on the parts from VPW that allow the use of the parking brake yoke to drive the vehicle. The complete process was basically remove parts, clean them and then put different ones back on. Without my students watching and moving my tools and parts around and my trying to explain what and why about everything under or in the M715, I should have taken no more than 30 minutes. The only problem that I encountered was the bolts that connnect the yoke to the drum. Mine came through from the back of the drum with the nuts on the driveshaft side. I tried putting them back on that way. The u-joint clamp bolts will not go in that way. I took the yoke back off and reversed the bolts so that the nuts were on the t-case side. My students were very glad that I had to take something apart and redo it. I used the nuts from the original u-joint u-bolts to secure the new u-joint clamp bolts. One other note, the castle nut on the brake yoke is a 1-5/16". I haven't driven it yet and will probably do a follow up post tonight about that.

Follow up,
It works as advertised and I can now hear everything else making noise. I really need to adjust my rockers, they are now the loadest noise. Before, I only heard them at fast idle.

Is it too early to tell about how hot it gets?

I have a dgital multi-meter with a celsius temp probe. Before the switch, I was getting 42-45 C after running 60mph for 5-10 minutes. I did the swap and changed the gear oil to 90w-130 yesterday. My temp when I got home was 41 C. I am going to pull a 2000 pound trailer with 3 round hay bales each about 1,500 pounds next week. That will be a twenty mile as fast as I can run 6,500 pound pull. I'll post my temps then. I also plan on doing a 60 mile highspeed run to a friends house a few weekends from no. That will let me know if I can keep this case, rebuild it or keep looking for a 205.

What was the total cost for the switch over?

I paid Vintage Power Wagon $175.00 including shipping for the parts, which are used take offs. I am going to move hay with it tonight. I will post my temperature readings tonight or tomorrow. I know that the price is about the same as many of you can find a divorced NP205 for. I have been unable to find one dispite months of looking for less than $300.00 with shipping. If my 200 works okay, I also don't have to build new mounts and shift linkage. Of course if it doesn't, I will have an extra $175.00 in a part I can't use. The joy of old vehicles.

I ran 21 miles in 24 minutes. Outside temp was 63 degrees. I had a 2,000 pound trailer hooked up. Up and down hills. I stopped, crawled underneath and put the probe next to the drain plug, next to the brake and at the top. All temperatures were between 74-78 degrees Celsius. That is about 180 F. I don't know if that is good or not. Nothing smelled bad and I had no noise from the t-case. Can anybody tell me if 180 degree at the case is good or bad? Thanks

I know this from having a gauge on my tcase filled with Eaton synthetic lube:
at 240 degrees the lube loses its ability to carry away heat and rapidly increases in temp unless the vehicle is stopped...though this heats it up for a period of time since it loses ram air and motion.
Running between 50 and 60 MPH for an hour or more on the highway on a hot day will heat my tcase to these temps. Running at the 50 mph point, and letting the truck slow down on hills will pretty much keep mine at 230 or below. Anything more than that will overheat the fluid and the temps will "runaway"...when this happened on the highway, the temp went from 240 to 280 in about 1/4 mile and when shut off soon thereafter, the temp exceeded the gauges 320 limit for quite some time before it dropped down.
My tcase had the gauge installed at the time when I moved the rear driveshaft to the straight through onfig but since I didnt know about the VPW kit at the time, I just ditched the ebrake altogether...so I have less parts there than you...
I do not have any numbers from before I moved the shaft to through drive.
brute4c

Brutes responce has left me with two questions: Where's the best place to install a temp gauge sensor and will bigger tires and a higher gear ratio...I'll be running 4.56... mitigate the overheating any or will it just mean that where Brute overheats at 60mph- I'll overheat at 70?

I know where a couple divorced 205 are sitting within a resonable drive for me...one even had a pto attached-but I'll bet it's gone by now. I was hoping to figure out how to use a divorced 203 range box then attach a 205- rumor has it that Ford- around '75 used a divorced 203 so if I'm gonna change out the t-case before I put the cab back on..... my as well go all out... just got to figure out if I can build the puzzle first.

For the tcase sending unit, get your sending unit and get a bushing that will screw into the tcase drain hole and let your sending unit screw directly ino that. Sticks down about 1 inch total, not bad. mine is a 1/8th thread and Mozarkid, thanks man, got me the bushing rom a hardware store near him...you might need to order it but its out there.
For the record, several people have driven these tcases at 60 and up mph for hours and have not had overheating problems...some like me do have this problem...many theorys abound as to why.
brute4c

Thanks for the temperature information Jon. I know you posted that several times on the old zone. I am also running SAE 90 lube that now has about 60 miles since I changed it. I plan to do a fast as I can run of more than 70 miles as soon as I get this alternator thing figured out. I will take temps and if they are still below the danger level Jon pointed out, I will change to 90w-130 lube and try again. if that works I will go ahead and put the expensive synthetic in, measure the difference and leave it. I will post results as I get things done in the next few months.

The Eaton I run is 75W-90..just so you know...
Good luck with your mission...be interesting what happens!!
brute4c

can you post a pic of the vpw kit installed on your truck?

Sure. I don't have a digital camera though. I will take pictures soon and get them developed and then scan them to the computer. Hopefully in the next two weeks you will be able to see it.

i'll be waiting. I started working on the T case today. I have to go into my storage unit to try to dig up my gear puller to pull off the old bearings. Or is there another way?

The bearings slide right off as far as I know. I haven't really disassembled the two output housings yet but the outer output bearings are a slip fit. You do need to press or hammer out the races if they are bad.

Chris

Yep I'm talking about the races. I'd be in trouble if I needed to press off the bearings.

I got to do an unexpected longer distance test of my t-case today. One of the teachers at my school blew her radiator up in her car yesterday in Brenham. Since I am the auto tech teacher, she asked me to fix it and if possible to go get it. The dissadvantage to having a car haul trailer. I figured it would be a good way to get more t-case temps. I drove the 33 miles at 3,200 RPM indicating 54 mph the entire way pulling a 2,000 pound trailer. No stops or slow downs on the four lane highway. I pulled into the parking lot and crawled underneath. I got all the way up to 97 degrees C at the hottest point, the drain plug area. That converts to 209 degrees F. Now I am starting to worry about overheating it. I also noticed that my rear main seal is just about gone. It wasn't running out in a steady stream from the clutch cover, but it was darn close with the engine off. I may have a good running but leaking 230, clutch and trans for sale real soon if it gets worse and I can't resist the 283 Chevy sitting in my shop just waiting to be run. I didn't get a temp from the return trip because I had to go onto my campus. This means waiting at the gate for the gate to open, sign in, wait for the inner gate of the sallyport to open and then drive at no more than 15 mph for half a mile to my classroom. I figured it would be an unfair reading and didn't bother. I did succeed in completely clogging up a brand new fuel filter in less than 150 miles though. I didn't notice it at speed or on the hills. It just wouldn't idle or pull at low speed. Tearing down the carb, blowing air in everything and putting it back on along with one of the two spare filters I carry fixed it in less than 15 minutes. I love impressing my students doing simple everyday things like that in what they think is amazing time. Welcome to the real world of working for a living where the more you get done, the more money you can make.

I will post any new temps that might develop. I will also try to finish out my roll of film soon and get that on here.

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I didn't get a temp from the return trip because I had to go onto my campus. This means waiting at the gate for the gate to open, sign in, wait for the inner gate of the sallyport to open and then drive at no more than 15 mph for half a mile to my classroom. I figured it would be an unfair reading and didn't bother.

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A sallyport? :!: :!: :!: Motorized gates? :shock: :shock: :shock:

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I love impressing my students doing simple everyday things like that in what they think is amazing time.

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By that, does that also include going off "campus" without someone searching your anus? :? Jees Louise, what kinds school do you work at? :roll:

Sounds like what I call a "facility" aka Prison. Or for the kiddies, Youth Authority. You work at a THUG school huh?......a sallyport...... that's the first clue :wink: .

I've always said there was two jobs I'd never do: SCHOOL TEACHER and PRISON GUARD... cause they're the same thing! :idea:

Be careful Tim! 8)

I work for the Texas Youth Commission. We have a fence around the campus. Other than that, it looks like a college campus. The students are between 13 and 21. With sentences from burglary to serial murder. I have never taught at a public school, but teachers that have tell me here is better. When a kid smarts off, I can correct the behavior myself or call one of the people whoes job it is to control them and they will take the kid away in handcuffs. I also don't have to do parent confrences or go to sporting events like publilc teachers. The kids in the vocational classes, which we have 10 different ones in different fields, have to earn their way into the programs, pass an interview with me and keep up good behavior or they are out. I joke with people that I teach convicted criminals how to use sharp power tools, but except for my female students that I have two hours a day, the students want to learn and the worst thing that could happen to them is to be taken out of my class. We also let the ones that can pass it take the ASE test. I think I have 8 ASE certified students in my class right now. I also get to work on my own stuff and get paid for it, that is worth any jokes you can make about being a guard or teacher.

Barrman, the "two jobs I'd never have" comment was not meant as a joke. I'm serious. I think that maybe next to "soldier" those might be the toughest jobs in America. I hear people say they'd never do my job... and trust me, it ain't hard and I get paid well.
I think it's cool that you are actually doing something that can make a difference. Sorry if that post was mocking or offensive to you. I know there is nothing better than to work with motivated people... makes work a pleasure instead of a burden. Didn't mean to be a jackass.....it just happens sometimes.