Auto tranny swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

old fart · 10-30-2007, 10:50 PM

I bought a transmission, transfer case and torque converter that I was told came out of a 1989 chevy 1/2 ton short bed pu. I got it to the house today and the driveshaft to the front end is on the drivers side. My 70 chevy SWB has the front driveshaft on the passenger side. Am I missing something here. I read posts on this forum about putting in a newer tranny with overdrive but I have not seen this problem posted. Is it possible the transfer case is wrong? How do I tell what tranny I have? 350,400,700r? Is there some way I can look at it and tell what it is? Can someone tell me how to identify the transfer case I have? Thanks for helping, Bill

RatRacer · 10-30-2007, 11:34 PM

This guy has a fairly good collection of info and links:

http://www.chuckschevytruckpages.com/

mrein3 · 10-31-2007, 08:07 AM

What most people do is swap out their th350 for a 700r4. MOST 70-72 4x4s with a th350 came with a NP205 transfer case. If you have a NP205 the swap is easier.

You buy the Advanced Adapters 700r4 in place of a th350 output shaft. You need to tear down the 700r4 to install the shaft so a rebuild at this time is a good idea. The 700r4 with this shaft will bolt up to the transfer case adapter that was behind the th350.

The 700r4 is amost 2 inches longer than a th350. Since the engine on a stock 4x4 is so far back you have room to move the engine forward. You need to move the cradle up this amount and bolt everything back together.

Then you need to worry about your fan. A different shroud or a conversion to electric fans will complete the swap.

Saturday morning I was helping the city install playground equipment in a new park. One of the volunteers from the neighborhood owns a new shop in the neighboring town. I asked what it would cost me to have him put in this shaft and rebuild the tranny with the latest upgrades. He said $800. So I'd need $800 plus ~$150 for the output shaft. ~$50 for the kit to hook the lock-up to the brake pedal switch. ~$100 for the TV cable set-up. $100 - $200 for a new torque converter.

I'm guessing it is about $1200 - $1300 for the conversion. I can still buy a lot of gas for $1200.

10-30-2007, 10:50 PM	#1
old fart Registered User Join Date: Oct 2007 Location: Amherst, NH Posts: 37	Auto tranny swap I bought a transmission, transfer case and torque converter that I was told came out of a 1989 chevy 1/2 ton short bed pu. I got it to the house today and the driveshaft to the front end is on the drivers side. My 70 chevy SWB has the front driveshaft on the passenger side. Am I missing something here. I read posts on this forum about putting in a newer tranny with overdrive but I have not seen this problem posted. Is it possible the transfer case is wrong? How do I tell what tranny I have? 350,400,700r? Is there some way I can look at it and tell what it is? Can someone tell me how to identify the transfer case I have? Thanks for helping, Bill __________________ 1970 k10 1967 C10 parts truck

10-30-2007, 11:34 PM	#2
RatRacer Registered User Join Date: Nov 2004 Location: OKC, OK Posts: 24	Re: Auto tranny swap This guy has a fairly good collection of info and links: http://www.chuckschevytruckpages.com/

10-31-2007, 08:07 AM	#3
mrein3 Registered User Join Date: Feb 2000 Location: Center City, MN, USA Posts: 3,253	Re: Auto tranny swap What most people do is swap out their th350 for a 700r4. MOST 70-72 4x4s with a th350 came with a NP205 transfer case. If you have a NP205 the swap is easier. You buy the Advanced Adapters 700r4 in place of a th350 output shaft. You need to tear down the 700r4 to install the shaft so a rebuild at this time is a good idea. The 700r4 with this shaft will bolt up to the transfer case adapter that was behind the th350. The 700r4 is amost 2 inches longer than a th350. Since the engine on a stock 4x4 is so far back you have room to move the engine forward. You need to move the cradle up this amount and bolt everything back together. Then you need to worry about your fan. A different shroud or a conversion to electric fans will complete the swap. Saturday morning I was helping the city install playground equipment in a new park. One of the volunteers from the neighborhood owns a new shop in the neighboring town. I asked what it would cost me to have him put in this shaft and rebuild the tranny with the latest upgrades. He said $800. So I'd need $800 plus ~$150 for the output shaft. ~$50 for the kit to hook the lock-up to the brake pedal switch. ~$100 for the TV cable set-up. $100 - $200 for a new torque converter. I'm guessing it is about $1200 - $1300 for the conversion. I can still buy a lot of gas for $1200. __________________ '70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN



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