Difference between suburban 1/2 & 3/4 ton?

[Big Ray]

ask around the diesel forum, there's been some discussion on mileage there.

 

[Big Ray]

mileage thread 1

mileage thread 2

 

[sweetk30]

http://www.grimmjeeper.com/gears.html

play with this to see the rpm at speeds diffrence.

and overdrive does help a lot.

th400 and 4l80e basicly the same just overdrive and lockup convt.

th350 and 700r4 and 4l60 series are basicly the same otherthan overdrive and lockup convt. but 700 and 4l60 get deeper first gear .

 

[nutt7]

Some got 14ffs and auto equipped would get the heavier auto. Bigger brakes and I would guess heavier frame.

The 3/4 frame is a tad thicker. Can't remember how much, but it is. With that and the 4l80, sounds like you should look for a 3/4 ton.

 

[imiceman44]

I would install a 14 bolt sf or FF if I needed to to make it a heavier duty towing truck! I have a 20 foot car hauler.

I'm curious if the frame was different or if the rear end was the only real change that was made? As I assume they all came with the 4l80e in 1991 regardless of the model?!

The frame is thicker on the 3/4 ton, the springs are heavier, and the 4l80e only came on the 3/4 ton 91.
So you are better off getting the 3.4 ton 91 if you are wanting to tow and want the stronger burb.

 

[Mav2u]

Yeah it is looking like the 3/4 ton in 454 is the most favorable setup to have!

 

[K588]

I had a newer 3/4T '99 454 4L80E 4.10's owned it for 10 years no matter what I did we could not average above 10 mpg. Even long trips with cruise control on flat ground driving like a granny.

 

[DarkandShiny]

Anybody have photo proof that the 3/4 ton suburban (1991) is more stout (i.e thicker, boxed sections) or otherwise different than the 1/2.

I've searched through the technical forums and I can't find any evidence the frames are different even though logic and everybody's statements indicate that it is so.

 

[nutt7]

Anybody have photo proof that the 3/4 ton suburban (1991) is more stout (i.e thicker, boxed sections) or otherwise different than the 1/2.

I've searched through the technical forums and I can't find any evidence the frames are different even though logic and everybody's statements indicate that it is so.

No photo proof, but read this

And here is the pic from the thread:

 

[DarkandShiny]

No photo proof, but read this

And here is the pic from the thread

Thanks Nutt!

 

[6.2Blazer]

I know it's not a 'burb but my '90 K5 with the 6.2, 3.73's and 700r4 averaged 18 mpg when stock when I bought it in '94 with 49k on the clock. That was running it hard around town and back roads as it saw very little freeway (i.e. better mileage times). When I retired it to play status and bought a 4-banger manual trans Toyota Tacoma as a daily driver I remember being disappointed that the mileage really wasn't any better. The only difference a 1/2 ton 'burb would have is being a little heavier. Obviously a 3/4 ton would get less because of the overall weight, but more importantly the rolling mass of the drivetrain is much greater with the trans and rear axle.

Believe '91 was the only square body 3/4 ton with the 4L80 (OD trans) with previous ones having the th400. I have never seen a 454 in a 4wd version square version, but I know the later years had them available.

There is more than the rear axle difference. Trans, rear axle, springs, cooling system, etc...

I like the 6.2 diesel both as a daily driver and off-road in most conditions...but it is NOT that powerful and in no way comparable to modern day diesels. It is a very simply and fuel efficient engine, not a torque monster. The 6.2 has less power than the TBI 350 but gets substantially better mileage.

 

[Mav2u]

No photo proof, but read this

And here is the pic from the thread:

Interesting!!