Rearend gear ratios 1980-1987 most common

[Ricko1966]

Ok this is purely for a little math problem I am working on. What was the most common rear gear put in a square with a th350? What was the most common rear gear put in a square with a 700r4.Not optional equipment, optional just the one that came most commonly when Joe blow went to the dealership in 1980 what ever and said I'll take the green one.

 

[1987 GMC Jimmy]

@Keith Seymore

 

[Swearbody]

Every square ive had that wasnt a 4wd after 81 had 3.08
My 82 350/350th 84 305/700r4 86's 350/350th
This leads me to think that 3.08 was super popular in 80's due to cafe regulations saying that a certain number of vehicles had to meet mpg rules. One was an hd optioned truck(stiffer front springs,7 leaf rear,bigger brakes etc.) and still had 3.08

Both my pre 80's 2wd(76-78) were 3.73 as well as my 82 4wd.

So just from that id say 3.08 or god forbid 2.7x. My brother has an 86 silverado with th350 and 2.7x and its a turd

 

[Craig 85]

My '77 K5 (400/TH-350/203) had 3.08's. My '79 K15 (350/350/203) had 3.08's. I've had 6 other Squares (3/4 and 1-tons) between 80 and 88. Five had 4.10's, my latest K30 is the only one that did not have a tow package and came with 3.73's.

 

[Bextreme04]

If you want real numbers, I suggest looking at the GM heritage vehicle information kits. They will tell you what the standard gear ratio was for every year and model. It also tells you what was available optionally for gear ratio. The biggest issue is that the vehicle information kits don't always show which transmission is standard, only the ratio that comes with the "auto" unless there are differences.

 

[TotalyHucked]

Most every 80s c10 I’ve seen has had either a 3.08 or a 2.73 in it. Mine is a 305/th350/2.73. Most overdrives I’ve seen had a 3.08. Same for 4x4 half tons, just about every one I see is 3.08.

The c20 and 30s, I’ll see 3.73 most common but some 4.10s and then camper special duallies usually came with either 4.10 or 4.56 and a th400


Sent from my iPhone using Tapatalk Pro

 

[legopnuematic]

My 76 and 79 c10s are both 3.08

The 85 c10 I parted was 2.73

All 3 are TH350 trucks.

 

[RoryH19]

87 R10 350/700r4 2.73
82 k5 305/700r4/np208 3.08
83 k5 305/700r4/np208 3.73
78 k10 350/th350/np203 3.08

Surprised the 83 got 3.73 from the factory.

 

[78C10BigTen]

My 78 (350/th350) was factory 3.08. I blew it up and swapped 3.42 in.

 

[Turbo4whl]

1982 C1500 w/305 and T350......wait for it, 2.56:1 The darn pinion gear was almost as big as the ring gear!

 

[TotalyHucked]

1982 C1500 w/305 and T350......wait for it, 2.56:1 The darn pinion gear was almost as big as the ring gear!

I thought mine was bad. You probably need 2 miles to get to 70! [emoji23]


Sent from my iPhone using Tapatalk Pro

 

[Turbo4whl]

I thought mine was bad. You probably need 2 miles to get to 70! [emoji23]


Sent from my iPhone using Tapatalk Pro

As you may have guessed, that gear set did not stay in there very long.

Hey, anybody need a 10 bolt 2.56:1 gear set with carrier?
Low mileage.

 

[Ricko1966]

If you want real numbers, I suggest looking at the GM heritage vehicle information kits. They will tell you what the standard gear ratio was for every year and model. It also tells you what was available optionally for gear ratio. The biggest issue is that the vehicle information kits don't always show which transmission is standard, only the ratio that comes with the "auto" unless there are differences.

How do I look this up?

 

[Ricko1966]

Thank you to everyone, sounds like 3.08 was most common for everything th350 or 700r4.That was the info I was looking for. I was mostly wanting to see If they changed the gear ratio for 700r4 ,seems like the answer is no..

 

[Bextreme04]

How do I look this up?

Here you go: https://www.gmheritagecenter.com/gm-heritage-archive/vehicle-information-kits.html