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andoboba · 09-16-2004, 12:17 PM

Quote:

Originally Posted by 59toaster

In 1988 GM had a body revision on the trucks.

The "round" body came out. GM had a contract to supply the Military with trucks for 10 years. They had to keep plants making the old body truck till they were sure they could fullfill the contract they signed in 82. So now GM was making two completly different full size trucks.

To diferentiate (sp) the old from the new the Round trucks kept the C 2wd and K 4wd designations. The Square body trucks became "R" 2wd and "V" 4wd. In 89 GM did a grill change to make the Square trucks sort of look like the round trucks from the front. They updated the interrior as well.
So on the Crew cabs, Suburbans, and Full size Blazer and Jimmy they were still the 73 body change plus cosmetic updates.

Now here is a Twist. While if you as a civilian ordered a 1988 K30 single cab or extended you got the new body. The Army was still geting single cab Square body trucks till 92.

These are hitting the market now for Gov auctions and cause a lot of confusion. Some folks didn't know they existed and those years are a BIG gray area to a lot of aftermarket people. You will find a lot of stuff not listing stuff for GM Subs and K5's for 88-91. You have to order the 87 parts to make sure you get the right ones and even that is a crap shoot. In 91 The 4L80 was installed in the trucks to replace the TH400. In 89 there were major revisons on the accessory drives including a reverseflow water pump on the surpentine. In 90 there was a new vairent of the 454 and it runs a unique FI to fit the old body to the new engine.

If you own a 88-91 R or V you better know what is what or your going to get handed a lot of wrong parts at Auto Zone or any of the chain places. \

Ohh I was wrong on something.

The S truck 10 bolt is a 7.5.

Thanks!!!!
I never knew what was going on with that R and V thing!
Chevy Trucks

andoboba · 09-16-2004, 12:18 PM

Quote:

Originally Posted by andoboba

Thanks!!!!
I never knew what was going on with that R and V thing!
Chevy Trucks

Oops,
Airstreams and GM Trucks

wayne.yl · 09-16-2004, 02:46 PM

Hey all
Sounds like alot got cussed and discussed while I was solving the rearend mystery to my tow vehicle. Thanks "toaster" for the ColoradoK5 web site. I was able to identify the axle on the burb. Its a dana 70. You were correct also in that both rear wheels must turn together to get the correct number of times the driveshaft turns in relation to the wheel. Turns out mine makes a little more than 4 full revolutions to 1 full wheel revolution. I guess I can assume the gear ratio is 4:10? Thanks to everyone in the discussion, I have learned a ton. I almost forgot the point "toaster" made about the fuel efficiency of my burb. I was not able to determine the original rearend of the truck before the 1 ton rear end modification. I did not find the RPO code of my suburban on the 1973-1987 code list. Anyway, until I find this out, I won't know what adjustment to make for the rear end I now have.
Wayne

59toaster · 09-16-2004, 05:38 PM

A D70!?!?!?!?!!

Wow thats a lot of axle for a Suburban!

There is a ton of sites that list RPO codes. Just put in RPO Chevy 1991 into Google and it should pull up several sites. Being a 91 I am pretty sure you started out with 3.42 or possibly a 3.73 but it would be very unlikely that you started with a 4.10 so you speedometer/odometer is reading wrong.

87MH · 09-16-2004, 05:58 PM

Quote:

Originally Posted by andoboba

.....You can identify this by looking for a casting number "60" on the lower portion of the housing just to the right of the pumpkin.....

I just crawled out from below the beast - the ONLY casting number I could find on the differential is on the LEFT side of the pumpkin and below the rear cover, on the back side, viewing from the rear forward. It clearly is "044" -- I don't think the "0" could be interpreted as a "D".

Any help in identifying what it is?

There are some numbers die stamped into the rear cover - 30809 333 5.

59toaster · 09-16-2004, 07:37 PM

Quote:

Originally Posted by 87MH

I just crawled out from below the beast - the ONLY casting number I could find on the differential is on the LEFT side of the pumpkin and below the rear cover, on the back side, viewing from the rear forward. It clearly is "044" -- I don't think the "0" could be interpreted as a "D".

Any help in identifying what it is?

There are some numbers die stamped into the rear cover - 30809 333 5.

It's a Dana 70 with the 10.54 ring gear. http://www.offroaders.com/info/tech-.../axlefacts.htm
Look on the casting on the left where the Roset weld it that retains the tube to the housing as well shape of the cover and any distigushing marks and compair it to the pictures in that link.

The numbers you show in the picture are going to refference stuff to Dana about the Casting it was produced from and proably bearing sizes for just the center section.

On one of the axle tubes will be stamped the SN#, PT# for the total assembly and date code. It's ususualy on the passengerside tube and visable from the back between the spring purch and the housing.

wayne.yl · 09-16-2004, 11:01 PM

Toaster
Given the fact that I have talked so much about this truck. I felt it would be fun to take some pics and post them. However. after several attempts. Im giving up until tomorrow.
Apparantly. the pics are too big to post. Maybe my 12 year old can figuire it out. He's way more tech literate than me. Should I be concerned about the rear axle we have been discussing, I mean is it appropriate for my burb?
Wayne

59toaster · 09-17-2004, 06:58 AM

Hehehe Yeah my Kid is starting to run me under the table on the computer too.

On the pictures you have to have them no larger then 640 wide by 480 high and under 250k of resolution. You an also hit the photo tab at the top and I think you can load a oversized photo to the photo album and then post the link.

wayne.yl · 09-17-2004, 02:24 PM

I spent some more time under my suburban looking for more confirmation of the axle and found the #s 70HD stamped on the left side of the differential where the axle housing connects. These numbers were on the left side as you are looking front to back. I gotta think they reference the Dana 70. Toaster, thanks for the help w/ the pics. Hopefully they will be forthcoming. Toaster, I have found the code for the original rearend. That gear ratio is 3:42. Now how do you determine the variance in gas mileage between the 4:10 gear?
Wayne