3-speed column swap to turbo 400 Help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

williars · 03-28-2004, 08:10 PM

Hello...I'm another new guy to your board. I am really enjoying the information you guys provide. Here is probably an old question to you members.
I want to switch out my 3 speed column and replace with a Turbo 400 automatic. Have any of you done this previously? And, do any of you happen to have a "how to" guide. I am fairly mechanically minded and could probably accomplish this task. I just don't want to miss something, and I really want the job to look factory. Any help you could provide would be greatly appreciated. Ryan

sneakysnake · 03-28-2004, 08:58 PM

Well first you need to make a shopping list,
tranny,drive shaft,flex plate, starter, AT cross member, AT column and linkage,AT radiator or a good cooler,to start with.
You will have to remove the existing crossmember, column is nearly a direct swap and remove the cluch pedal by undoing clamp on the shaft rod and spring and slide out,after you get it all in place measure your drive shaft and have it cut to fit.
I know its not a step by step but I hope this helps.

JimKshortstep4x4 · 03-28-2004, 09:11 PM

I don't have a "how to" guide but I can get you started anyway.
I would recommend a service manual for your year truck, also.

Parts needed:

Auto column complete with your year setup on the shift indicator including the fiber optic cable and socket.

Auto linkage, rod, frame mount, frame to transmission

Flex plate

TH 400 yoke, check drive shaft length, may have to cut

Auto transmission crossmember, TH 400 has two brackets for
e-brake, but TH 350 cross member will work

Rear transmission mount

Kickdown switch and wiring for your year truck

Installation

Remove transmission and old frame members

Remove, clutch components, including pressure plate disc and linkage, be carefull removing clutch rod from pedal linkage as there may be a spring. Remove flywheel and replace with flex plate.

Grind off frame bracket for clutch "Z": bar.

Install transmission and transmission cross member

Replace TH 350 yoke on driveshaft with TH 400 yoke. Note you may be money ahead to get a TH 400 driveshaft instead of trying to match a yoke up to your driveshaft. Install driveshaft.

Remove old column and install auto column.

There are obviously some things that are left out, but that is the quick version. Above all else, do everything with safety in mind.

Good luck!

Jim

bigskiohio · 04-01-2004, 04:02 PM

also you will need to splice in your nuetral switch inline with the purple wire from switch.

chevytrux · 04-01-2004, 06:17 PM

Ryan, The info you already recieved is good. You also will need the 400 kickdown switch and harness as it is electrical. I have all the parts you need and ship daily. If you are interested in some or all of them [and free info], please call me @ 510-651-5874 days. Good luck.
Bill @ Vintage Chevy Trucks

03-28-2004, 08:10 PM	#1
williars Registered User Join Date: Mar 2004 Location: Waldorf, Maryland Posts: 23	3-speed column swap to turbo 400 Help Hello...I'm another new guy to your board. I am really enjoying the information you guys provide. Here is probably an old question to you members. I want to switch out my 3 speed column and replace with a Turbo 400 automatic. Have any of you done this previously? And, do any of you happen to have a "how to" guide. I am fairly mechanically minded and could probably accomplish this task. I just don't want to miss something, and I really want the job to look factory. Any help you could provide would be greatly appreciated. Ryan __________________ Ryan 69 Camaro 396 Yenko Clone 71 Cheyenne SWB 402 69 C-10 Stepside 454 4speed 83 Scottsdale Stepside 350/Auto 99 Mustang GT In the works: 67 Chevy II Nostalgia Straight Axle Blown 427

03-28-2004, 08:58 PM	#2
sneakysnake It's a catastrophic success. Join Date: Jan 2003 Location: Oklahoma Posts: 2,077	Well first you need to make a shopping list, tranny,drive shaft,flex plate, starter, AT cross member, AT column and linkage,AT radiator or a good cooler,to start with. You will have to remove the existing crossmember, column is nearly a direct swap and remove the cluch pedal by undoing clamp on the shaft rod and spring and slide out,after you get it all in place measure your drive shaft and have it cut to fit. I know its not a step by step but I hope this helps.

03-28-2004, 09:11 PM	#3
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	I don't have a "how to" guide but I can get you started anyway. I would recommend a service manual for your year truck, also. Parts needed: Auto column complete with your year setup on the shift indicator including the fiber optic cable and socket. Auto linkage, rod, frame mount, frame to transmission Flex plate TH 400 yoke, check drive shaft length, may have to cut Auto transmission crossmember, TH 400 has two brackets for e-brake, but TH 350 cross member will work Rear transmission mount Kickdown switch and wiring for your year truck Installation Remove transmission and old frame members Remove, clutch components, including pressure plate disc and linkage, be carefull removing clutch rod from pedal linkage as there may be a spring. Remove flywheel and replace with flex plate. Grind off frame bracket for clutch "Z": bar. Install transmission and transmission cross member Replace TH 350 yoke on driveshaft with TH 400 yoke. Note you may be money ahead to get a TH 400 driveshaft instead of trying to match a yoke up to your driveshaft. Install driveshaft. Remove old column and install auto column. There are obviously some things that are left out, but that is the quick version. Above all else, do everything with safety in mind. Good luck! Jim

04-01-2004, 04:02 PM	#4
bigskiohio Registered User Join Date: Sep 2003 Location: Ohio Posts: 127	also you will need to splice in your nuetral switch inline with the purple wire from switch.

04-01-2004, 06:17 PM	#5
chevytrux Registered User Join Date: Jul 2002 Location: Fremont, Ca. Posts: 26	Ryan, The info you already recieved is good. You also will need the 400 kickdown switch and harness as it is electrical. I have all the parts you need and ship daily. If you are interested in some or all of them [and free info], please call me @ 510-651-5874 days. Good luck. Bill @ Vintage Chevy Trucks



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