Differential ID please

[jim85K5]

Ok Boys and Girls a newbie needs some help in ID'ing this rearend set up. It is on an '85 4x4 Suburban, 6.2L Diesel, 208. What I know (or think that I know) is that it is a GM Corp. 14 bolt, 9 1/2". When both rear tires off the ground one rev of the right rear tire gives me 1.75 revs of the drive shaft (+/-). Sometimes the tires will turn and the driveshaft does not. Guress I should say that when you rotate one tire the other turns with it. This is in Neutral with the Emergancy brake off.
If you do know what this rearend is I am interested hearing what you have to say as far as how good or bad it is.

Thanks to one and all,

Jim

 

[Hogback Fabrication]

Yeah, its a SF 14 bolt. You should also learn to resize pictures. My guess for gear ratio is either 3.42 or 3.73.

 

[74757685k5]

0pen diff . if you want to find your gear ratio spin only one tire 2 times and count D shaft revs.

 

[neverendingproject]

or find two first two numbers you see on the ring gear. take the second one, divide by your first one, and you have your ratio.

 

[jim85K5]

The numbers on the gear are 11 and 47. Looks to me like I have a 4.27. If this is an open diff. is it correct that both wheels will spin together when jacked up??

Once more THANKS for all the help!

Jim

 

[74757685k5]

one will spin forward and one reverse.

 

[atho]

I'm betting its 11 and 41, which is 3.73.
the only vehicles i've heard of using 4.27 are old jeep cj's and scout 80/800s.

 

[neverendingproject]

Doesnt look like an open diff.

 

[bablazer73]

From this side it looks like a "gov-loc" type posi unit. the ring gear on the inside Is the give away. I bet there is a set of weights on the other sidetahts geared to that ring gear. Gov-locs are not known to be strong. They are made to "wind-up" before engagement. Very often will act like an open diff until the centrifical force and weights activate the locking mechanisms.

 

[neverendingproject]

Well i just got a gov lock (look for "is this a posi or gov-lock in my 14sf" in the garage section) and it turn freely. you have to yank it pretty good to lock it by hand, but otherwise, one shaft this way, the other shaft, that way.

here http://coloradok5.com/forums/showthread.php?t=156697

 

[thatK30guy]

Thats definitely NOT an open dif. Thats the Gov-bomb. At least on the 10 and 12 bolts they are known as GB's. 14 SF and FF's GB's are stronger than the smaller axles and will live longer than them, too.