overdrive for a k20

[nekkidhillbilly]

im new to the forum

but anyhow i dont care about it holding crazy amounts of power on anything so my question is what can i do about putting a od tranny to this be it a 700r4 2004r 4l80e or something of the wall even

cheapest is best

[Prong]

Cheapest route would be a 700R4 and NP208 T Case out of an 80's 3/4 ton. You may also need the driveshafts if they don't make a conversion U-joint.

[nekkidhillbilly]

wasnt the np208 in the half tons also

another question what about the later trucks transfer case the 241 or what ever its called can i use it and the 700r4 out of say a 92 or will it mess with the shifter location or something

[nekkidhillbilly]

truck is a 84 btw

[kevinr1970]

Originally Posted by nekkidhillbilly

wasnt the np208 in the half tons also

another question what about the later trucks transfer case the 241 or what ever its called can i use it and the 700r4 out of say a 92 or will it mess with the shifter location or something

I think if a 3/4 ton truck/Sub had an OD tranny they also had a 208 TC. I think they are considered "light duty".

I am 99% sure the newer body trucks (88+) and Sub's (92+) have a driver side drop transfer case so I would look out for that.

I would do some number crunching before making the swap. If you are not in need a of a tranny anyways it will take quite some time for the tranny swap to pay for itself even if you get all the parts for quite a deal.

[nekkidhillbilly]

im not dropping a fully built unit in this thing just something from a junk yard i can swap in

my 200-4r i got for my car cost me 50 bucks. its a gn one too and had a 700r4 offered to me for 200 bucks so i cant see it being a big cost. i have no clue about drivers side drop what does tha mean. im not wanting a off road machine or anything just something i can do 65 in and get better than 6 mpg. i have an 04 to tow with and all.

i have considered getting the tbi 350 4l80 and transfercase from a later truck and mounting in the 84 but the issue again is the transfer case drive shaft mods arent a issue i can have them modded cheaply.

[nekkidhillbilly]

ok i read up figured out that the new trucks have the drive shaft on the drivers side

so can i use something from a dodge ford or what

sorry for all the questions im new to these trucks

[Gleekr]

for sure the cheapest/easiest is to find a complete trans/transfer combo from a 82-87 truck or 82-91 blazer/burban with the later trucks watch for the electronic speedo that some had

[Russell]

You can bolt a 32 spline NP208, or pass side drop to any transmission from a newer truck. All of them use the same 6 bolt round transfercase output.

I've got an 04 NV3500 transmission in my 1980 with a NP241 transfercase from a 91 Suburban, everything bolted straight together. The transmission even bolted straight up to my 6.2L without any adapters either. I didn't even have to change my driveshafts!

[nekkidhillbilly]

what trucks have this transfer case and a 4l80 will bolt to it

[Russell]

You can bolt any 32 spline NP208 or 32 spline 6 bolt round pattern NP205 from any 81 - 87 truck, Burb, K5 or 3+3, or any NP241 from an 89-91 Burb, K5 or 3+3 up to a 4l80e

[nekkidhillbilly]

Originally Posted by Russell

You can bolt any 32 spline NP208 or 32 spline 6 bolt round pattern NP205 from any 81 - 87 truck, Burb, K5 or 3+3, or any NP241 from an 89-91 Burb, K5 or 3+3 up to a 4l80e

really ok then my is a 84 k20 with a 205 so it should just bolt right in

will i have to move it back or anything

[Russell]

So long as your NP205 is 32 spline then it should bolt right up to the 4l80e. I don't know the exact length of a 4l80e, so I am going to side on the edge of caution and say you should expect to be replacing your transmission crossmember, and having to adjust the length of your driveshafts.

[nekkidhillbilly]

truck is a 3/4 ton them and the th400 are pretty close so i could move the engine a foward if needed