Transmission Swap Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

GTSideSwipe · 10-24-2015, 03:42 PM

Hi. So I have a question regarding swapping out my turbo 400 on my C20. It's the original 400 with a two piece drive shaft. I am wondering if there are any overdrive transmissions that would work so I wouldn't have to do anything like cutting the drive shaft.

EARNHARDT#3 · 10-24-2015, 05:03 PM

What length tail shaft do you have? If it's 4" then the 2004r and 700r4 are pretty close.

GTSideSwipe · 10-24-2015, 05:27 PM

Quote:

Originally Posted by EARNHARDT#3

What length tail shaft do you have? If it's 4" then the 2004r and 700r4 are pretty close.

I'm not sure which tail I have but I will be able to check on Monday. I have a 700R4 tranny that is laying around in my garage so I was thinking about swapping in to lower the rpm a bit especially at freeway speeds but just am not sure.

Thanks for the info.

57larry · 10-24-2015, 05:32 PM

is the drive shaft yoke the same on a 400 & 700R4?

GTSideSwipe · 10-24-2015, 05:39 PM

Quote:

Originally Posted by 57larry

is the drive shaft yoke the same on a 400 & 700R4?

No. You will have to use a different yoke. It looks like the 700R4 4L60E TH350 are the same but the 400 is different.

hugger6933 · 10-24-2015, 06:01 PM

If you use you3/4 ton like a 3/4 ton, you want to look into the 4L80E trans but here is the downside, it has to have its own controller. Those can run you in the $300 to up on the controller and each do nothing without it. I 4L80E is built stronger from the factory than a 700R4 that has been Modded to some small degree but can take plenty abuse.
So if hauling or towing get the 4L80E. Lots of drive line places can do a drive shaft using what you have for less than a hundred bucks, Jim

Clavo106 · 10-24-2015, 06:18 PM

Quote:

Originally Posted by EARNHARDT#3

What length tail shaft do you have? If it's 4" then the 2004r and 700r4 are pretty close.

thank for sharing that picture. makes mock ups more easier.

10-24-2015, 03:42 PM	#1
GTSideSwipe Registered User Join Date: Oct 2015 Location: Puyallup WA Posts: 127	Transmission Swap Question Hi. So I have a question regarding swapping out my turbo 400 on my C20. It's the original 400 with a two piece drive shaft. I am wondering if there are any overdrive transmissions that would work so I wouldn't have to do anything like cutting the drive shaft.

10-24-2015, 05:03 PM	#2
EARNHARDT#3 Registered User Join Date: May 2014 Location: PA Posts: 1,417	Re: Transmission Swap Question What length tail shaft do you have? If it's 4" then the 2004r and 700r4 are pretty close. Attached Images __________________ 1967 C10, LWB, 250, Powerglide, PS, PB, 3/4 STATIC DROP

10-24-2015, 05:32 PM	#4
57larry Registered User Join Date: Nov 2007 Location: Indianapolis Posts: 1,161	Re: Transmission Swap Question is the drive shaft yoke the same on a 400 & 700R4?

10-24-2015, 06:01 PM	#6
hugger6933 Registered User Join Date: Oct 2008 Location: Marianna Arkansas Posts: 7,280	Re: Transmission Swap Question If you use you3/4 ton like a 3/4 ton, you want to look into the 4L80E trans but here is the downside, it has to have its own controller. Those can run you in the $300 to up on the controller and each do nothing without it. I 4L80E is built stronger from the factory than a 700R4 that has been Modded to some small degree but can take plenty abuse. So if hauling or towing get the 4L80E. Lots of drive line places can do a drive shaft using what you have for less than a hundred bucks, Jim



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