Trans question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

RoadDevil13 · 01-04-2010, 01:30 AM

Im wondering about swapping my TH350 for a 700r4....anyone know if this is a pretty straight forward swap or am I going to have to mod the driveshaft/etc ??

My pickup is a 72 2wd C10 longbed. I just dont know enough about the differences in the trans cases to know how much is involved. I am sure this swap would improve fuel economy and highway driving......

Any help/suggestions are appreciated

**LEEVON** · 01-04-2010, 01:51 AM

First off, welcome to the board!

The swap is pretty straighforward. Cutting the driveshaft depends on short or long tail TH350. The biggest things are driveshaft, moving the trans crossmember and setting up the TV cable. The rest is small stuff such as a longer speedo cable, adjusting the shift linkage etc.

The best way to gather information would be to use the main search function at the top of the page, then do a keyword search for 700r4 using the "title only" pull down. You will find days and days of reading.

Longhorn Man · 01-04-2010, 11:30 PM

since you have a 3.07 gear (assuming the truck came with an automatic originally) then your MPG may actually go down by adding the 700R4

RoadDevil13 · 01-04-2010, 11:33 PM

Quote:

Originally Posted by Longhorn Man

since you have a 3.07 gear (assuming the truck came with an automatic originally) then your MPG may actually go down by adding the 700R4

Thanks for that info.... probably not somewhere I want to go with it then. I have no plans of reinventing its drivetrain.

Thanks

01-04-2010, 01:30 AM	#1
RoadDevil13 Registered User Join Date: Dec 2009 Location: Henderson, NV Posts: 52	Trans question Im wondering about swapping my TH350 for a 700r4....anyone know if this is a pretty straight forward swap or am I going to have to mod the driveshaft/etc ?? My pickup is a 72 2wd C10 longbed. I just dont know enough about the differences in the trans cases to know how much is involved. I am sure this swap would improve fuel economy and highway driving...... Any help/suggestions are appreciated Last edited by RoadDevil13; 01-04-2010 at 01:33 AM.

01-04-2010, 01:51 AM	#2
LEEVON Moderator Join Date: Jul 2006 Location: Ozark, MO Posts: 4,893	Re: Trans question First off, welcome to the board! The swap is pretty straighforward. Cutting the driveshaft depends on short or long tail TH350. The biggest things are driveshaft, moving the trans crossmember and setting up the TV cable. The rest is small stuff such as a longer speedo cable, adjusting the shift linkage etc. The best way to gather information would be to use the main search function at the top of the page, then do a keyword search for 700r4 using the "title only" pull down. You will find days and days of reading. __________________ '86 GMC C30 Crew ~ '86 C20 Crew ~ '79 K15 Sierra Grande ~ '76 Blazer 2wd ~ '74K10 ~ '71 Cheyenne swb ~'50 3100 bagged ~ '80 Wife ~ Late model kids Last edited by LEEVON; 01-04-2010 at 01:51 AM.

01-04-2010, 11:30 PM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Trans question since you have a 3.07 gear (assuming the truck came with an automatic originally) then your MPG may actually go down by adding the 700R4



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