Manual to automatic trans conversion - The 1947 - Present Chevrolet & GMC Truck Message Board Network

1984 t type · 12-24-2010, 04:15 PM

Hey guys, just picked up my new project today :-) it's a 85 suburban 4x4 with a 350 with all the California smog crap still in place and a manual thanks that refuses to go into any gear other than reverse. No prob because I don't care for stick shifts as my daily drivers and that's what this is going to be, so with that being said here's my question : What all do I need to install a 700r4 trans into it and is it as easy as swapping out transmissions or is this going to be a not so straight forward swap? I guess this is a good time to mention that I have never owned or worked on a 4x4 truck before but I am capable of working on cars and have done trans swaps before just never on a truck. Thanks in advance for your help and guidance
Posted via Mobile Device

bmchevy1979 · 12-24-2010, 04:36 PM

well you would need the trans, transfer case, crossmember, drivelines, shifter or column(with shifter), detent cable w/ brackets, and wiring it in I think it is mostly a bolt in thing besides wiring for lockup

wiring here
http://73-87.com/7387garage/drivetrain/lockup.htm
adjustment
http://73-87.com/7387garage/drivetrain/tvcable.htm
calibration for speedo
http://73-87.com/7387garage/drivetrain/speedo.htm

1984 t type · 12-24-2010, 04:38 PM

So I couldn't reuse the current transfer case ?
Posted via Mobile Device

bmchevy1979 · 12-25-2010, 02:32 AM

not positive but if you get the right adapters and input shaft for transfer case maybe

1984 t type · 12-25-2010, 07:44 PM

ok i just read this somewhere tell me if its correct or not
the 700r4 and 350 have a 27 spline count and the 400 and manual trans have a 32 spline count. so if that is right i need a transfer case that came out of a truck with either a 700r4 or 350 correct ? also would a 350 cross member work or does it have to be from a truck with a 700r4 ? will these parts work from a k blazer ?

bmchevy1979 · 12-26-2010, 11:30 AM

I cant believe I am the only one that has chimed in but there is a difference in the two not sure but it has to do with the tailshaft on the 700r4 because you can buy a tailshaft for it to bolt it up the mounting pattern is the same and with the shaft you can use the th350 adapter

shaft kit
http://offroaddesign.com/catalog/trannyoutput.htm

12-24-2010, 04:15 PM	#1
1984 t type Registered User Join Date: Nov 2010 Location: MICHIGAN Posts: 196	Manual to automatic trans conversion Hey guys, just picked up my new project today :-) it's a 85 suburban 4x4 with a 350 with all the California smog crap still in place and a manual thanks that refuses to go into any gear other than reverse. No prob because I don't care for stick shifts as my daily drivers and that's what this is going to be, so with that being said here's my question : What all do I need to install a 700r4 trans into it and is it as easy as swapping out transmissions or is this going to be a not so straight forward swap? I guess this is a good time to mention that I have never owned or worked on a 4x4 truck before but I am capable of working on cars and have done trans swaps before just never on a truck. Thanks in advance for your help and guidance Posted via Mobile Device

12-24-2010, 04:36 PM	#2
bmchevy1979 Registered User Join Date: Dec 2010 Location: Visalia, Ca Posts: 707	Re: Manual to automatic trans conversion well you would need the trans, transfer case, crossmember, drivelines, shifter or column(with shifter), detent cable w/ brackets, and wiring it in I think it is mostly a bolt in thing besides wiring for lockup wiring here http://73-87.com/7387garage/drivetrain/lockup.htm adjustment http://73-87.com/7387garage/drivetrain/tvcable.htm calibration for speedo http://73-87.com/7387garage/drivetrain/speedo.htm __________________ <Brandon> 1974 Chevrolet K5 Blazer 350sbc/SM465/NP205, dana44 front, corp 14bolt rear with 4.10s and a powertrax locker, custom rear bumper 400sbc in the works. 1981 GMC C1500 stepside 250i6, 3spd, 12bolt with 3.08s 2.5/4drop on 15x10 with 275/50r15 81 GMC C3500 cab-chassis dually with utility bed 350sbc, Sm465, 14bolt with 4.10s nv4500 getting ready to go in 1979 Chevrolet K5 R.I.P. http://67-72chevytrucks.com/vboard/s...d.php?t=434096 1976 Chevrolet C10 R.I.P. http://67-72chevytrucks.com/vboard/s...d.php?t=434195

12-24-2010, 04:38 PM	#3
1984 t type Registered User Join Date: Nov 2010 Location: MICHIGAN Posts: 196	Re: Manual to automatic trans conversion So I couldn't reuse the current transfer case ? Posted via Mobile Device

12-25-2010, 02:32 AM	#4
bmchevy1979 Registered User Join Date: Dec 2010 Location: Visalia, Ca Posts: 707	Re: Manual to automatic trans conversion not positive but if you get the right adapters and input shaft for transfer case maybe __________________ <Brandon> 1974 Chevrolet K5 Blazer 350sbc/SM465/NP205, dana44 front, corp 14bolt rear with 4.10s and a powertrax locker, custom rear bumper 400sbc in the works. 1981 GMC C1500 stepside 250i6, 3spd, 12bolt with 3.08s 2.5/4drop on 15x10 with 275/50r15 81 GMC C3500 cab-chassis dually with utility bed 350sbc, Sm465, 14bolt with 4.10s nv4500 getting ready to go in 1979 Chevrolet K5 R.I.P. http://67-72chevytrucks.com/vboard/s...d.php?t=434096 1976 Chevrolet C10 R.I.P. http://67-72chevytrucks.com/vboard/s...d.php?t=434195 Last edited by bmchevy1979; 12-25-2010 at 11:52 AM.

12-25-2010, 07:44 PM	#5
1984 t type Registered User Join Date: Nov 2010 Location: MICHIGAN Posts: 196	Re: Manual to automatic trans conversion ok i just read this somewhere tell me if its correct or not the 700r4 and 350 have a 27 spline count and the 400 and manual trans have a 32 spline count. so if that is right i need a transfer case that came out of a truck with either a 700r4 or 350 correct ? also would a 350 cross member work or does it have to be from a truck with a 700r4 ? will these parts work from a k blazer ? __________________ 1987 Buick Grand National 2018 Road Glide Special

12-26-2010, 11:30 AM	#6
bmchevy1979 Registered User Join Date: Dec 2010 Location: Visalia, Ca Posts: 707	Re: Manual to automatic trans conversion I cant believe I am the only one that has chimed in but there is a difference in the two not sure but it has to do with the tailshaft on the 700r4 because you can buy a tailshaft for it to bolt it up the mounting pattern is the same and with the shaft you can use the th350 adapter shaft kit http://offroaddesign.com/catalog/trannyoutput.htm __________________ <Brandon> 1974 Chevrolet K5 Blazer 350sbc/SM465/NP205, dana44 front, corp 14bolt rear with 4.10s and a powertrax locker, custom rear bumper 400sbc in the works. 1981 GMC C1500 stepside 250i6, 3spd, 12bolt with 3.08s 2.5/4drop on 15x10 with 275/50r15 81 GMC C3500 cab-chassis dually with utility bed 350sbc, Sm465, 14bolt with 4.10s nv4500 getting ready to go in 1979 Chevrolet K5 R.I.P. http://67-72chevytrucks.com/vboard/s...d.php?t=434096 1976 Chevrolet C10 R.I.P. http://67-72chevytrucks.com/vboard/s...d.php?t=434195 Last edited by bmchevy1979; 12-26-2010 at 11:31 AM.

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