1971 GMC with manual 4 spd-what is the stock ratio??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

57rookie · 03-24-2018, 08:33 PM

So, i don't have any ratio listed on my glove box option sheet. What do the experts say was the std axle ratio for a truck that came with a 350 and a 4 spd manual. The 4 spd seems to have a very low granny gear in 1st....
Thanks for the future opinions.

Noah96 · 03-24-2018, 08:37 PM

Is the truck a half ton 3/4 ton or 1 ton? Also original motor and trans?

**Already Gone** · 03-24-2018, 08:40 PM

Here ya go.. I am assuming its a GMC 910 but I've added the GMC 920 specs as well.

57rookie · 03-24-2018, 08:50 PM

It is a 1/2 ton 1971 GMC. I was hoping for the 3.07!! I dont want to pull the cover off as it is very original and no leaks...

Mike C · 03-24-2018, 09:08 PM

Quote:

Originally Posted by 57rookie

It is a 1/2 ton 1971 GMC. I was hoping for the 3.07!! I dont want to pull the cover off as it is very original and no leaks...

That would suggest the fluid was all original. And I'm pretty sure that it could use a change, a fresh gasket as well as a pinion seal...

Rear diffs are typically abused in the sense they get zero maintenance until they are broke or worn out.

**Already Gone** · 03-25-2018, 03:47 AM

Quote:

Originally Posted by 57rookie

It is a 1/2 ton 1971 GMC. I was hoping for the 3.07!! I dont want to pull the cover off as it is very original and no leaks...

Looking at the posted chart and if there is no optional ratio on the spid then you should have 3:07..

LILREDGMC · 11-22-2018, 07:49 PM

Second owner of a 71 GMC with 465 4 speed. SWB and it is a 3:07, now a 355 sbc still the 4 spd and 3:07

LILREDGMC

03-24-2018, 08:33 PM	#1
57rookie Registered User Join Date: Jul 2011 Location: Calgary, Alberta Posts: 153	1971 GMC with manual 4 spd-what is the stock ratio??? So, i don't have any ratio listed on my glove box option sheet. What do the experts say was the std axle ratio for a truck that came with a 350 and a 4 spd manual. The 4 spd seems to have a very low granny gear in 1st.... Thanks for the future opinions.

03-24-2018, 08:37 PM	#2
Noah96 Registered User Join Date: Aug 2016 Location: Danville Wv Posts: 266	Re: 1971 GMC with manual 4 spd-what is the stock ratio??? Is the truck a half ton 3/4 ton or 1 ton? Also original motor and trans?

03-24-2018, 08:40 PM	#3
Already Gone 70+ ( Old Skool Club ) Join Date: Nov 2003 Location: Saskatoon, Saskatchewan ,Canada Posts: 9,068	Re: 1971 GMC with manual 4 spd-what is the stock ratio??? Here ya go.. I am assuming its a GMC 910 but I've added the GMC 920 specs as well. Attached Images __________________ 1972 C10 Custom/Deluxe 613 Highlander 406/700R4 1999 White Tahoe LS 4x2 with Z56 Police Package 1992 K1500 GMC Suburban Members I have personally met: MusicMan70 - HeavyD - ChewyChevy67 - StingRay -71SWB4x4 - 67 Burb - DeadheadNM - too much stuff - bc65 - das601 " Circumsatances Do Not Change Responsibility " " The Sky is not the Limit, Your Mind is." Marilyn Monroe .. RIP Charlie Watts 1941 - 2021

03-24-2018, 08:50 PM	#4
57rookie Registered User Join Date: Jul 2011 Location: Calgary, Alberta Posts: 153	Re: 1971 GMC with manual 4 spd-what is the stock ratio??? It is a 1/2 ton 1971 GMC. I was hoping for the 3.07!! I dont want to pull the cover off as it is very original and no leaks...

11-22-2018, 07:49 PM	#7
LILREDGMC Registered User Join Date: Oct 2001 Location: Pittsburgh, Pennsylvania USA Posts: 461	Re: 1971 GMC with manual 4 spd-what is the stock ratio??? Second owner of a 71 GMC with 465 4 speed. SWB and it is a 3:07, now a 355 sbc still the 4 spd and 3:07 LILREDGMC



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