So, wait a minute, you've got a southern short bed standard cab GMT800 that is drivable, and you may be replacing it. You might be able to sell it up north without fully fixing it for more than you could down there after fixing it.
So, wait a minute, you've got a southern short bed standard cab GMT800 that is drivable, and you may be replacing it. You might be able to sell it up north without fully fixing it for more than you could down there after fixing it.
Didn't the 2wd Escalades come with a 5.3 and 4l60e?
How hard would it be to put a 4l80 in there?
Any love for the 6l80e in the 07-15 Escalade/Denali, 09-15 Tahoe, 08-13 Avalanche? Same 440ft/lb rating as the 4l80e, but a lower 1st and a very slightly taller overdrive. IIRC road tests put those at a full second faster 0-60 than 4l80e equipped trucks just because of the more favorable lower gears. With that 4.03 1st gear vs a 2.48 in the 4l80e you could potentially use a 4.8 or 5.3 with a taller rear and still have good around town acceleration with low RPM cruising for better mpg. Hell-stick with the 6.0 and still have an around town beast that doesn't need to shift out of overdrive while loafing along on the highway.
In reply to MrJoshua :
I want to avoid AFM so that's why I'm looking pre 07.
In reply to eastsideTim :
I might just do that but I want to keep life simple.
Stampie said:In reply to newrider3 :
No and that is an option also. Is that trans reliable?
Internet lore says the NV4500 is bulletproof, aside from requiring special fluid, YMMV.
My personal experience says that's accurate, but my sample size is small. There's a '93 K2500 that's been in my family nearly 20 years now with the 6.5/NV4500 combo and it shifts great and has never had problems; while I owned a '97 F350 7.3 Powerstroke for about a year once upon a time and it munched two ZF5 trans in that time period, while also having the shift feel of a spoon in a cup of frozen yogurt.
The NV4500 is a good trans in my experience. The NV3500 in most of the 1500 trucks is acceptable if you're gentle with it but is very sensitive to fluid type and level. They generally eat the intermediate shaft bearings.
I have had a few GMT400s and GMT800s, and while the 5.7 Vortec with the 4L60 does a good job if you retune the transmission calibration (I have 290k miles on one and 200k on the other) it doesn't have extra power to go around. Towing a car or a small enclosed trailer means locking it in 3rd gear and expecting to use 2nd up any real incline. It will do it, it's just tiring. The 4L80 with the 5.7 benefits from the tighter gear spacing in the 4L80 and most of them have a short enough final drive to make it work. Never had a 454 GMT400.
The earlier TBI trucks get a pass from me. Had one, 5.7 5 speed, too weak for towing even modest loads in modern traffic unless it is just local stuff. They get great gas mileage when running right.
GMT800 tahoe 5.3 4wd - feels much weaker than the 5.7 vortec GMT400s unloaded or towing the same loads. Overall a more "civilized" truck, but actually gets worse gas mileage too by a few mpg.
My trip/hauler is now a GMT800 Suburban 8.1. 10 mpg towing an enclosed trailer at 75 mph vs. around 8 trying to do the same thing with one of the GMT400s. Downside is 13 mpg unloaded. Torque for days. The tune in these is kind of strange, both on the engine and trans side. Very easy to get a bit more power out of them and move the shift points down since they seem to shift really late stock. The 8.1 does not feel like it needs more than 4 gears, though I've never driven one with an allison. A buddy has a 6.0 suburban 2500 and we go on a lot of the same trips - he only gets about half a mile per gallon better than I do. We both have 6x12 enclosed trailers, and his is routinely kicking down where mine stays locked up in 4th unless I'm really getting after it. Very relaxing tow vehicle.
The pickups were available with the 8.1 and the ZF6. That's the unicorn combo, and will allegedly knock down 14-15 mpg.
Somebeach (Forum Supporter) said:In reply to Curtis73 (Forum Supporter) :
Do you know if the Allison's bolt up to the same transfercases as the 4l80 or the 4l60 or are they there own bolt pattern and shaft splined?
Good question. I know that they all use an adapter tube, so one would hope that you just need the right tube from the right trans. Most of the AWD T-cases were a BW with a viscous coupling, and most of the 4x4 cases were NP, so that might be problematic. To the best of my knowledge there was never an Allison with AWD.
I'm sure the aftermarket has you covered - Novak-adapt or Advanced Adapters might have what you need.
Also, when I use the term 4L60E, I'm referring to the whole family, including 4L65 and 4L70. The 4L65 stepped up from a 3-gear planet set to a 5-gear which dramatically ups it's torque capacity. The 4L70E added hardened billet input guts and is at least rated for as much torque as a 4L80E. I would still lean toward the 4L80E simply for clutch diameter. Big clutches is one of the keys to torque capacity simply because of the leverage they have. What I'm saying is, the 4L70E might have the torque capacity in the hard parts, but something about the 4L80E and it's bigger clutches gives me a warm fuzzy feeling. I mostly mention it to point out how you can get 4L80E-like torque capacity in the same bolt-in space as a 4L60E if you're not keen on adapting.
Stampie said:In reply to newrider3 :
No and that is an option also. Is that trans reliable?
Behind a mild 6.5TD, yes. They're not bad in the shift feels either. NV5600 is the granddaddy, but they are expensive because they came behind Cummins. ZF6 is another great unit.
eastsideTim said:So, wait a minute, you've got a southern short bed standard cab GMT800 that is drivable, and you may be replacing it. You might be able to sell it up north without fully fixing it for more than you could down there after fixing it.
I had a customer bring in a Tacoma for a PPI and the frame was three strips from being broken, and we advised he return it for a refund, and he said "Well, it was only $10,000..."
Erk.
As far as towing, I have never felt a need for more power, just more handling/stability and more brakes. I have been perfectly happy with a 4.8. I mean, I'd be towing in 3rd to save the trans anyway, right?
Difficulty: Ohio hills are relatively tame. Never had an issue pulling out to pass at 60-65mph going up the longer steeper grades. Have never needed full throttle, ever. Never felt comfortable going over 75 either 
if'n I were to buy a tow rig it would probably have a V6. Gut feeling is that a V8 sized water pump and radiator with a V6 sized water jacket would make for cooler running.
In reply to Pete. (l33t FS) :
I agree with you, and I'm constantly torn on the HP/TQ towing thing. I towed my boat a lot with a 170hp/220tq V6 and it required a lot of shifting, but it did the trick without being so slow that I was a nuisance to traffic. I think one of the reasons I tend to choose more oomph for towing is that I get a (perhaps misguided) warm fuzzy feeling when I'm only using 1/2 throttle instead of redline with my foot to the floor. On the one hand I know that topping the hill at X mph requires Y hp, so the stress in the cylinders is basically the same regardless of whether I'm using every pony from a 200hp mill, or using half throttle from a 400hp mill, but there is something to be said for accessories, crankshafts, piston pins, connecting rods and their experience with that cylinder pressure at 3000 rpms versus 5500 rpms. There is also a significant part of my brain that knows I want to GET up to speed quickly as well as be able to maintain it. Things like on-ramps, pulling out in traffic, etc.
This is one of the reasons I don't totally focus on horsepower for towing, and I actually don't even focus that much on torque. I focus on displacement. You can always get the same output at lower RPMs with more cubes.
So, Stampie, I've already bench-built your truck. You need a 3/4 ton GMT400 with a Caddy 500, a switch-pitch TH400, and a gear vendors OD. Enjoy.
And yes... no substitute for chassis stoutness. Brakes, frame stiffness, tire load and appropriate sidewalls, axle weight capacity.
In reply to Curtis73 (Forum Supporter) :
I've only got a 472 laying around will that do?
In reply to Curtis73 (Forum Supporter) :
Arguably they are under less stress at higher RPM because there is less piston force on the rods and mains, the oil pump is theoretically moving more fluid through the bearings to keep them cool, etc.
This is speaking of being in the same engine family of course. Big blocks have bigger everything, and Diesels are on another level altogether! I would feel really guilty hammering an 8.1 at 4000rpm or a Diesel at 3.
In reply to Stampie :
A 472 will do great. Just add turbo :)
So I thought a lot today and researched. Perfect for me would be GMT800 Tahoe with a 6.5 turbo and NV4500 swap. Yeah Curtis was right those swap parts are up there. So next is find a GMT400 Suburban with a 6.5 turbo. Take auto but prefer manual. Just from looking today that'll be a unicorn. Anyway no rush because in the meantime I'll buy back my truck and get a rebuilt title pretty quick. That'll at least get me back to where I am with money in my pocket to be able to buy the above. I might still hit up the people that have the 8.1 GMT800 because who doesn't love BBC?
I picked up an 09 express 2500 with a 4.8 and 4l80 last winter for so cheap I almost felt bad buying it.
It tows like a boss, I only wish I'd been able to find a passenger van so I wouldn't have had to add the second row of seats myself.
In reply to Stampie :
That's a shockingly good idea
In reply to Dusterbd13-michael :
Says the man that likes to do burnouts.
In reply to Stampie :
Which is a shockingly bad idea for me.
Stampie said:In reply to 1SlowVW :
Damn it man.
Mine now has a bed in the back but with that you could have an apartment. And a work bench!
Edit: you may as well just lock this up now. There are no better options.
Stampie said:In reply to 1SlowVW :
Damn it man.
Perfect!
Curtis73 (Forum Supporter) said:And yes... no substitute for chassis stoutness. Brakes, frame stiffness, tire load and appropriate sidewalls, axle weight capacity.
This! This can NOT be stressed enough! HP/TQ/displacement, all have their places in a towing discussion. But these need to be addressed first 
Curtis73 (Forum Supporter) said:In reply to Stampie :
A 472 will do great. Just add turbo :)
My wife, unfortunately, is literally allergic to diesel - the fumes from the fuel itself, as well as the exhaust. My next travel set up, now that we do not travel for work, will be gas. Would love to do a caddy, but with a MT behind it. Don't currently have a start for that, so a built 460, is probably gonna be the torque monster used!
Stampie... I didn't see a price in that van, but I LOVE that body! Ya buy it yet?
In reply to 03Panther :
Trade the wife for a Duramax? Just spitballing ideas.
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