HELP finding out specifications on 87 3/4 4x4 Sub

[Flymuch]

I am a newly annointed member and quite frankly a pretty marginal shade tree mechanic and have just a aquired an 87 3/4 ton 4x4 Suburban with a 350 in it. I have lots of ideas, but wanted to first clarify what I am dealing with. I have not found anyway to clearly ID what is on the truck since I have no build sheet.

Can anyone tell me how to find out what:
- transfer case it has
- transmission it has (it is 3 speed by the way)
- front/rear differential (14 bolt rear and 10 bolt front)
- ...what gear ratio they have
- and recommended upgrades

It has a mild 2 1/2 in lift and that seems plenty for me since this can not be wheeled many places due to its size. I have a no interest in body lifts and would prefer the ride quality of stock (or better) but with much improved performance that covers highway cruising to camp sights where wheeling can be done and fire road type stuff. I defintely have a soft spot for baja style off roading. So why a suburban? So I can haul the family to camping sights and OHV areas that allow offroad exploration and not having to take a huge trailer or camper.

I have enjoyed watching from afar, but the fun begins now.

Thanks in advance to all for your suggetions and comments.

 

[cuervo]

Inside the glove box should be a sticker that has a bunch of letter/numbers. These will tell you everything the truck came with.

My guess for an 87, if stock, is a 350/700r4/NP208.

 

[jor]

Yea, the label in the glovey has all of the RPO codes (Regular Production Option). Just query for "rpo" and you'll find many sites that list all the codes for your Suburban. Here's a photo of my label (87 Suburban) along with my notes when I was researching it.
jor

List Price: $12,477
Model: R/V (‘R/V” includes pickups, blazers & Suburbans, “V” is 4WD)
GVW: 6200-7000
Motor: 5.7L TBI LO5 (the “LO5” is the RPO (Regular Production
Transmission: THM 700-R4 (RPO is MD8), shift points controlled by TV, Throttle Valve Cable
Option number for the 5.7 TBI)
Built: Flint, MI

CAPACITIES
Oil: 5 quarts with filter
Water: 18 quarts (with A/C)
Differential: 2 quarts
Transfer Case: 5.2 quarts

 

[4X4HIGH]

Since you know it's an 87 model and a 3 speed trans then it would be a TH400 with a NP208 t-case (assuming it's original still). Being a 3/4 ton it will be a 10 bolt front axle and either a 14bff (full floater) or a 14bsf (semi-floater) rear axle. To determine which rear axle just look at the axle from the side of the vehicle, if there are 8 bolts in the center(ish) of your wheel then it's a 14ff otherwise it's a 14sf axle. Also the 14sf axle has a more round pattern to the cover.

 

[cuervo]

DOH! he did say it was a 3 speed tranny. I need to read more before I hit the reply button.