Manual Transplant in the aut'Hoebot

[chaingun427]

Planning on doing an NV4500 swap into my white 98 Tahoe. It's currently a 4l60e/np246 autotrac setup so I'm trying to compile all of the information I'll need to do the swap in one place. The donor is a 2000 k2500 4wd with an NV4500 and an np241. it's been rolled but still starts and shifts fine.


For the most part it seems fairly straight forward, at least at first. The old motor tranny and transfer are already out and gone which leaves me with just the motor.
The easy part is the mechanical assembly,
1. pull dash, steering column, and carpet out of the front.
2. install clutch pedal, and brake pedal after knocking out hole in firewall
3. cutout floor pan for shifter and 4wd shift lever (based on measurements from the donor if it's not already stamped) not cutting carpet at this time
4. install pilot bearing, new pressure plate and clutch
5. mount transmission only, drill new locations for the cross member
6. install transfer case and attach 4wd shift linkage
7. driveshafts( not sure if I can use the front from the donor) Will need to find correct shafts if existing won't work.
8. connect and bleed slave cylinder
9. disconnect and remove tccm

Electrical is going to be the big issue with this swap as i've got a few big questions i haven't answered yet.
1. wire vss from np241 into rearmost speed sensor from the 246 (green and purple)
2. splice pink and green wires on the shift selector to enable reverse lights
3. wiring harness near the shift linkage connects to front axle to engage it, as well as the 4x4 indicator light? (according to Btempy on fullsizechevy. Ground one end wire,Cut the Grey/Black-possibly light blue? wire on the actuator and splice it into the 3rd wire coming from the pigtail. middle wire goes to the 4wd light?)


The biggest issues I think I'm looking at are going to be
How do i wire up the front axle actuator to the shift linkage?
Does the 4wd indicator have constant hot, and the transfer case just completes the circuit?
Should I swap in the manual computer from the donor, and if so how do i rewire the fuel pump to send the fuel level to the computer first? IIRC that started in 99

As always advice and insight are appreciated, I'd like to get this build on the road by the middle of summer if at all possible.

One further complication will be the 383 stroker i'm building, i'm not sure if the clutch assembly from the 350 will work on it or not...

 

[chaingun427]

My other option is of course to rebuild the np246 (with the wear plate to prevent pump rub of course) and swap over the input shaft from the NP241 to keep the auto trac and simplify the overall swap. my primary concern there is of course the magnesium case on the 246, and whether the tccm will work properly with a manual transmission

 

[SunlitComet]

246 will work with manual in hoe just like it did in truck as long as you carry over parts that are needed. Cross reference part numbers off TCCM axle actuators and all that. Better then trying to convert to a second sticker.

 

[chaingun427]

That's what I've been thinking all day as well, since ask the wiring and such is already in place, and the overall length of the drive train would only change by 1/8th inch so I could retain my existing shafts. I think the only serious issue with the 246 is pump rub which I can alleviate with a $25 part. The fun part is going to be swapping the input shafts out, from what I'm gathering the clearance has to be just right

 

[chaingun427]

Any thoughts on the fuel level wiring? I'm thinking of using the 2000 computer since it's already manual tuned but I know that starting in 99 they routed the fuel level through the ecu before it hits the gauge

 

[ccapehartusarmyINF.(ret)]

thats a pretty low geared tranny for just a tahoe
does it have the granny low or the ultra low
i think the ultra low one has like a 6.31 ratio for first gear you could pull your house of its foundation with that low of a ratio

 

[chaingun427]

Not sure I think its like 6.56:1 for granny. Final drive is close to the 4l60 though at .75:1.

Edit:it's a 2000 so it's 5.61:1 for low and .73:1 for final drive for comparison the 4l60e is .696:1 for final drive. I'll be marginally less efficient on the highway by the numbers, but i'll lose less power through the drive train so i'm hoping it will make up for it

 

[xanatost]

Subscribed! I will be doing this to mine in about a year (I hope)

 

[chaingun427]

Hope everything I run into will be helpful, will you be going for a full transplant like i'm doing or will you just do the transmission?

 

[chaingun427]

The donor motor

Spent most of the day getting the front clip dissasembled and all of the plumbing undone