4spd/Rockwell to TH350/205 swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Hallz · 06-20-2008, 02:33 PM

Hello everyone,

I just purchased a 67 3/4 ton long bed with a 327,4spd, & I believe a Rockwell transfer case. My question is I have a brand new TH 350 and the 205 transfer case that was going to go back into my 79 long bed. However I got rid of it a few months back.

I really want to swap out the 4spd & Rockwell for the TH350/205 set up. I assume that I will have to change the cross member and lengthen/shorten the driveling as well.

In addition A floor mount shiftier and new levers for the 205. Can anyone fill me in on what I missed or will need to accomplish this in a day/weekend.

Thanks all,

**Yukon Jack** · 06-20-2008, 04:29 PM

Welcome to the board! This thread will help you a bit I hope.

Big68 · 06-20-2008, 05:16 PM

I went the other way on my swap, but to each his own.

The only thing that I see you'll need that you don't have listed is the flex-plate to bolt the torque converter to, and a vacuum line to run to the transmission. Two simple things that will bring your project to a screeching halt.

As long as you've got all of your parts( even down to the bolts and mounts), you should be able to get the whole thing done in a weekend. Maybe even a very long day.

Good Luck,

Adam

Hallz · 06-20-2008, 06:04 PM

Thanks guys,

Yeah I have the flexplate, I do need to buy a new stock converter though. I am only swapping out to a auto so it will be easier for the woman to drive. Even then if it was not for the whine in the transfer case or trans I would just have her get use to it. But from the reading the Rockwell is a b!t<h to get parts for so I figured it would be easier to swap it vs repair it.

Any tips on isolating the whine to the transfercase or tranny?

Also, I may hold off a bit till I put a small lift on it to clear the 35's I got with the truck.

*FormerMember* · 06-21-2008, 07:19 AM

Quote:

Originally Posted by Hallz

Also, I may hold off a bit till I put a small lift on it to clear the 35's I got with the truck.

The lift would affect driveline length. I would do it once, at the same time, if you're going to do it.

hdflstf · 06-21-2008, 12:42 PM

Don't forget to remove the pilot bushing from the crankshaft, otherwise the torque converter will never fit.

**Yukon Jack** · 06-21-2008, 10:38 PM

The Rockwell's whine quite a lot so unless your low on gear oil, probably nothing unusual.

scott123 · 06-23-2008, 08:33 AM

i went from a 3 speed/rockwell to the 350/NP205 just recently...had to shorten the back drive shaft and lengthen the front...i had to heat and bend my shifter because it didnt want to center the hole in the floor board. and you will also have to change the radiator if yours does not have cooling line option...running new transmission lines as well....if your radiator has the cooling line options flush them because all kinds of dirt, grease and crud will end up in your new transmission....not sure if it is a weekend deal, unless you prebend your lines, and have everything handy to make the swap...miine ended up being a two weekend deal... good luck...scott

Hallz · 06-26-2008, 04:41 PM

Thanks,....I have a external Trany cooler with a fan and will be running HP rubber lines.

I will also be using a floor mounted cable shifter for the TH350, I assume your talking about bending the levers for the 205 correct? What levers did you use and what about the cross member?

I may just put the new sb 406 I have sitting in the garage in with it and know the motor & trans are both new.

Thanks,
Mike

06-20-2008, 02:33 PM	#1
Hallz Registered User Join Date: Jun 2008 Location: Sacramento Posts: 20	4spd/Rockwell to TH350/205 swap Hello everyone, I just purchased a 67 3/4 ton long bed with a 327,4spd, & I believe a Rockwell transfer case. My question is I have a brand new TH 350 and the 205 transfer case that was going to go back into my 79 long bed. However I got rid of it a few months back. I really want to swap out the 4spd & Rockwell for the TH350/205 set up. I assume that I will have to change the cross member and lengthen/shorten the driveling as well. In addition A floor mount shiftier and new levers for the 205. Can anyone fill me in on what I missed or will need to accomplish this in a day/weekend. Thanks all,

06-20-2008, 04:29 PM	#2
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,683	Re: 4spd/Rockwell to TH350/205 swap Welcome to the board! This thread will help you a bit I hope. __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

06-20-2008, 05:16 PM	#3
Big68 Registered User Join Date: May 2008 Location: Macon, Ga Posts: 15	Re: 4spd/Rockwell to TH350/205 swap I went the other way on my swap, but to each his own. The only thing that I see you'll need that you don't have listed is the flex-plate to bolt the torque converter to, and a vacuum line to run to the transmission. Two simple things that will bring your project to a screeching halt. As long as you've got all of your parts( even down to the bolts and mounts), you should be able to get the whole thing done in a weekend. Maybe even a very long day. Good Luck, Adam

06-20-2008, 06:04 PM	#4
Hallz Registered User Join Date: Jun 2008 Location: Sacramento Posts: 20	Re: 4spd/Rockwell to TH350/205 swap Thanks guys, Yeah I have the flexplate, I do need to buy a new stock converter though. I am only swapping out to a auto so it will be easier for the woman to drive. Even then if it was not for the whine in the transfer case or trans I would just have her get use to it. But from the reading the Rockwell is a b!t<h to get parts for so I figured it would be easier to swap it vs repair it. Any tips on isolating the whine to the transfercase or tranny? Also, I may hold off a bit till I put a small lift on it to clear the 35's I got with the truck. Last edited by Hallz; 06-20-2008 at 06:05 PM.

06-21-2008, 12:42 PM	#6
hdflstf Registered User Join Date: Oct 2007 Location: Desert Southwest Posts: 540	Re: 4spd/Rockwell to TH350/205 swap Don't forget to remove the pilot bushing from the crankshaft, otherwise the torque converter will never fit.

06-21-2008, 10:38 PM	#7
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,683	Re: 4spd/Rockwell to TH350/205 swap The Rockwell's whine quite a lot so unless your low on gear oil, probably nothing unusual. __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

06-23-2008, 08:33 AM	#8
scott123 Registered User Join Date: Dec 2007 Location: Middleburg, North Carolina Posts: 480	Re: 4spd/Rockwell to TH350/205 swap i went from a 3 speed/rockwell to the 350/NP205 just recently...had to shorten the back drive shaft and lengthen the front...i had to heat and bend my shifter because it didnt want to center the hole in the floor board. and you will also have to change the radiator if yours does not have cooling line option...running new transmission lines as well....if your radiator has the cooling line options flush them because all kinds of dirt, grease and crud will end up in your new transmission....not sure if it is a weekend deal, unless you prebend your lines, and have everything handy to make the swap...miine ended up being a two weekend deal... good luck...scott

06-26-2008, 04:41 PM	#9
Hallz Registered User Join Date: Jun 2008 Location: Sacramento Posts: 20	Re: 4spd/Rockwell to TH350/205 swap Thanks,....I have a external Trany cooler with a fan and will be running HP rubber lines. I will also be using a floor mounted cable shifter for the TH350, I assume your talking about bending the levers for the 205 correct? What levers did you use and what about the cross member? I may just put the new sb 406 I have sitting in the garage in with it and know the motor & trans are both new. Thanks, Mike



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