Best O/D Tranny for 73 K10

[sokoloka]

Current drivetrain is 350/T350/NP203. Would like to swap in more modern overdrive tranny - what's the best option to sandwich between the 350 / NP203?

Does the answer change if I eventually plan on swapping in a newer 5.3 / 6.0 at some point down the line?

 

[COCHEV]

Easiest might be to do a th700 and 208 combo. Prob not worth the time to adapt a 203 to a newer trans. Just my opinion.

 

[big dan]

Is your current tranny still working?

If you are planning an ls swap I would hold out and do one of the computer controlled overdrive autos at the same time. That way you could have a better tranny and not have to run a stand alone computer/wiring harness.

 

[diesel4me]

I'd go with NO overdrive...seems to me the overdrives dont live long unless completely rebuilt with mods and stronger parts,big coolers,and then still die young sometimes..to me the extra 3 mpg you may gain isn't worth it in the long run--the money you spend on an overdrive tranny will but a lot of gas...the TH350 and TH400's hold up better in my opinion than a 700R4 in stock form will..

If you plan to go with a late model EFI engine "eventually",I'd just get the engine and tranny from one and do it all at once..the 4L80E overdrive is pretty much a TH400 with overdrive,but it needs the computer to run it right..so you may as welll get everything in one package and do it once..

 

[Greg Ducato]

The 700 is easiest, it will require a custom output shaft to work with your current adapter and transfer case. You will need to alter both driveshafts. Same thing applies to driveshafts on a 700/208 swap though you do gain a lighter transfer case that is part time which will help. I agree that if contemplating he conversion to an LS engine you hold out for a 4L60E and maybe even a 241C out of a 90-91 model to get the speed sensor you will need, though it won't drive your speedometer.

 

[82355]

Toss the NP203 in the iron pile while you are at it.

Oh, and NV4500 is the correct answer.

Martin

 

[blazinzuk]

you really don't have a ton of options here, 4l80 4l65, 4l60 ( 700)

NV 4500 thats about it really.

I think you will be fine with the 700 lots of haters out there.

I have blown up tons of th350s never a 700 though. Of course i have had lots more 350s than 700s

 

[paratrooper307]

In stock form, a 700 isn't the strongest, but with the right parts they can hold 500, 600hp or more, and if you are staying with an automatic, they are about the cheapest way to get OD.

 

[Stomis]

Allison 1000 FTW

 

[tRustyK5]

Tremec T6060 and divorced 205...have it all.