tranny question again. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

slick78 · 05-19-2010, 05:16 PM

i got a straight six with a three speed on my 78 stepside.i wana convert it to automatic.what tranny fits and what would i have to change?i know i gota change a couple things im just not sure.thanx.

Turbo85GMC · 05-20-2010, 07:26 AM

I would think that a TH350 would be a fairly straight forward swap. You'd probably have to relocate or swap the trans crossmember. You would definately have to add a trans cooler, either swap to a radiatior with one or add a seperate one. Just some thoughts, I'm sure others will chime in too.

You might want to ask over on the Engine & Driveline forum. You'll probably find at least a few people over there who have done the same thing already.

05-19-2010, 05:16 PM	#1
slick78 Registered User Join Date: May 2008 Location: salinas,california Posts: 144	tranny question again. i got a straight six with a three speed on my 78 stepside.i wana convert it to automatic.what tranny fits and what would i have to change?i know i gota change a couple things im just not sure.thanx.

05-20-2010, 07:26 AM	#2
Turbo85GMC Registered User Join Date: Apr 2005 Location: Medford, MA Posts: 307	Re: tranny question again. I would think that a TH350 would be a fairly straight forward swap. You'd probably have to relocate or swap the trans crossmember. You would definately have to add a trans cooler, either swap to a radiatior with one or add a seperate one. Just some thoughts, I'm sure others will chime in too. You might want to ask over on the Engine & Driveline forum. You'll probably find at least a few people over there who have done the same thing already. __________________ '85 GMC 1500 "Friends don't let friends drive stock!"



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