Hope this will help decipher the Suburban platforms strengths and weaknesses
The Suburban marketing badge is the longest contiguous running badge in automotive history. GMC abandoned that whey they dropped Suburban for Yukon XL
MotorTrend wrote:
The Suburban is undisputed as the oldest surviving nameplate in the U.S., dating back to 1935. The first Suburbans were essentially station wagons built on truck frames. In 1955, the Suburban name was also used on a GMC truck called the two-door Suburban Carrier. The Suburban is now in its 12th generation and is among the largest passenger vehicles on the road
Mine is a 1996 K3500 Suburban with: 7.4L Big Blck, 8.6K GVWR, 4,250 FGAWR, 6,000 RGAWR, 10,000 MTWR and 16,000 GCWR (took a long time to find that one, as GCWR was not common when ordered my Suburban...still not easy to find that rating today). Platform is GMT400
Tongue and cheek reference mine as a K3500, as ordered it with the F60 option, which is the snow plow prep that begets 1 ton front torsion bars....and the rear axle is the same as the 1 ton dually of that year (same AAM axle assembly and GM varies the spring pack) and mine has the 1 ton dually rear shoe brakes (I've changed out the MC and cylinders to the larger dia 1 ton dually)
GMT800 platform begot the 8.1L big block, which has about 40 ft/lbs more and about 50HP more than my 7.4L. They do spin a bit faster and part of why they have a bit more HP than mine.
There were complaints of 'piston slap', rattle, etc and none that I know of really made a difference. The main info found talking to GM engineers was that their 'new' to them, piston coating and machining required longer break in and warm up and that noise abated till the next cool down and start
The frames of GMT400 and GMT800 were pretty much the same as the pickups these SUV's were derived from. Next gen GMT900 had more changes and not much like the pickups they still were derived from. Hydro-forming of the fame made it easier/economical to have different frame sections.
The big change on the GMT900 is the receiver....also dropped the big block and soon the 2500 altogether. It is now part of the Suburban's frame (welded onto it) and is part of the rear bumper (marketing listening to the Fashion Statement Crowd who don't tow much, nor heavy...so it is no longer 'ugly' and integrated into the bumper...visually)
Because now part of the bumper...crash and crumple zone duties apply and the why the bracket/gusset from cross tube to frame rail has notches...stress raisers to 'crumple'...but...that 'designed in stress raiser' (AKA weak spots) no limit the receiver's ratings to a max WD of 1,000 lb tongue weight
AS noted, there are 1 ton Suburban's, but commercial and tow rating is less than the 1500 civilian version
As for the auto tranny...it is a beast, but needs a low (high numeric) diff ratio. As it's 1st gear ratio is NOT a good one for towing heavy. There are 1,000 HP up to 2,000 HP 4L80E/4L85E that has 3 year warranty's out there. Not much more than a GM crate automatic and should last many years past that 3 year warranty....if you don't use it at +1,000 HP...
That automatic is on my list of stuff for the rebuild/update of my 1996 Suburban
Bump the ICE with a cam, tuner and whatever else decided when that time come.
5.X diff ratio
GearVendors 0.5 ratio OD unit to provide an 8 speed automatic
Maybe headers, but the stock manifold setup has it so hot in there, can't put my hand in there...the ambient air is so hot. Gotta be ceramic coated to manage that...
Not much engine bay room for a turbo, but am okay with that in mid-section or even way back there...throttle response isn't that important, but towing heavy at altitude is...
The fuel tank for GMT400/GMT800's are 42 gallon. Saw a 54 gallon offering about 20 years ago, but that firm is gone now
Am also noodling a tune and the need for premium (42 gallons), but that is the price to pay to play...
Mine used to smoke the tires in first any time, any place...no more, as at +163K miles, it is showing its age. Also direct throttle linkage, so no fly by wire and the why the locals with Suburbans/YukonXLs/Ford F150's don't get why can still leave them...'cuz while their computers are deciding which power mode to allow...mine has already gone there (4.1's makes a big difference and part of they why want 5.x's)
On that, mine has 16x10 Alcoa alloy's with a 1.5" negative (old term was positive) offset. Stock is 1.5" positive. 1.5" plus 1.5" = 3" more track...times 2 = 6 inches wider track than stock. Stock is 6.5" rim width, bead to bead. 10 - 6.5 = 3.5 more track width. Tires are 20mm wider to boot. So my track is about 10.5" wider than stock.
Marry that with KYB MonoTube Shocks and mine corners like on rails. It never leaned much and with the above setup, can yank the steering wheel at speed and drift all fours...throttle/brake initiate oversteering/understeering to leave those newbie guys panicking in the middle of a curve they 'tried' to follow me into...after challenging me on the freeway.
Yup, boy racer stuff and has been in my blood since the early 60's....but....only when hot rod'ing alone or with like buddies. This all translates into a higher ability to 'manhandle' a Mr Murphy moment while towing or anytime...
The biggest weakness, for me, is the transfer case. Depending on which year you find/buy...there is a kit to fix one issue. That is the output shaft moves and rubs a hole in the case. Less than $100 kit
Good luck!!!
