Regearing for better towing.

[juddspaintballs]

1999 6.5L Suburban K1500 with 280k on the clock but only 220k on the motor.

It's nearing the end of it's life as a family truckster and will soon be replaced with a Volvo XC90 for toting the tots. I just bought a tractor for the property and will need to pick up a bumper pull trailer to haul it around every now and then. I don't think that it's up to the task of towing around 10k+ as it sits right now. I believe I have 4.10 gearing in the Suburban. I hate the IFS on there too. The Suburban won't be anyone's daily driver very soon.

I've been thinking about it, and once I replace it as a family vehicle, I want to do a solid axle swap. I don't particularly need taller tires or a lift on it, but I want a solid front axle. When I do that swap, I'm considering re-gearing to a better ratio for towing. 4.56 ratio, perhaps? I can swap in a 14 bolt FF in the rear at the same time and ditch the SF I currently have.

As it sits right now, the Suburban struggles to maintain 70 mph up over our little mountains with a 5x10 utility trailer and about 1000 lbs on it. It's not a fuel issue, I believe, based on all of the fuel system upgrades I did this past summer. It's not an exhaust issue with the 4" diamond eye exhaust. The PMD is new and mounted on a heat sink in the grille. The transmission is only a couple years old. My manual wastegate opens at 14 PSI and the turbo frequently goes over 10 PSI going up the hills with that load. When the transmission drops out of OD, I'm pegging 14 PSI the whole way up the hill and losing speed. EGT's are still in the safe range. Stock computer. I think gearing might be my issue.

To do the swap I wanna do will cost me a good chunk of change. The axles themselves aren't incredibly expensive (D44 front, 14 bolt FF rear). Re-gearing them will start costing money. The spring mounts for the front won't be too hateful, but all of the other little bits that go with it start to add up like cross steering, new springs, etc. I'll be honest, I don't want to start dropping too much $$$ if I can avoid it. It's got a little body damage, the hood is peeling, a rear barn door is starting to rust and so is the rear bumper, and there are many tiny little annoyances that need replaced or fixed. I only want to make it work until I can get a newer diesel pickup to safely tow my tractor around. The thrill of the project does make me want to still do it, though. Hey, I converted my s-10 blazer from the 4L60e to a NV3500 after 205k miles because I prefer a 5 speed.

Any thoughts? Is the gearing (most likely) my issue?

 

[WarWagon]

IT IS NOT!!! It is rated for 1/2 that. Half ton - get it? Pulls 1/2 of what you want it to... :hihi:

You need a 3/4 ton with a big block to tow that. Although the hitch is rated for 10,000 LBS on the 3/4 ton burbs (454) the 6.5 diesel option takes it down to 7500 LBS for the trailer.

The lack of power you feel is the asthma attack turbo. Gearing for higher RPM runs that stupid small turbo GM gave us where it doesn't want to be: over 2200 RPM and you loose power. If anything you need to gear lower and lug the hell out of it under 2200 RPM. Oh wait! Don't have enough power down low RPM either.

6.5L has a nice BD diverter valve and ATT setup for sale on here you would really enjoy in the hollers out yonder. Still won't tow what you want with it.

http://www.campinglife.com/tow-ratings-database/

Year Make Model Engine Tow Limit
1999 Chevrolet/GMC Suburban K1500 (4WD) 6.5 V-8 TurboDiesel 5000 LBS

 

[THEFERMANATOR]

ALL K1500 diesel BURBS had 3.42 gears in them from GM. With 4.10's they can pull pretty good, but it runs out of RPM's pretty quickly IMO. I had 4.10's, and I know running 70 in 3rd was just about the redline.

 

[juddspaintballs]

I knew the hitch wasn't up to the task and would be replacing it.

So what you're saying is...it's a lost cause at this point and I should cut my losses. I did consider a 454, actually. But, I have little to no need to have a Suburban in the very near future so I might as well buy an interim pickup truck until I get what I want (2003-2006 24 valve Ram 3500). I've even considered a V10 Excursion for a future 12 valve conversion, but taking on a project of that scale winds up being cheaper to just buy what I want.

 

[WarWagon]

If you don't use it much a 454 3/4 ton pickup will do the job. Cheap to buy. Sure 6 MPG, but, you can buy a tanker truckload of premium gasoline for the $10-20K price difference. Yeah, 10K is all she wants (my 1993) with a weight distribution hitch. I would hate to try this with a 1/2 ton as the brakes etc. just weren't up to par unloaded. Of course the 6.5's are 'heavy 1/2 tons' vs. the light 1/2 tons. 5 vs. 6 lug wheels, brakes, etc.

You can look for the HD trucks that have a inexpensive 6.5 diesel add the turbo BD combo and do the job at 10 MPG. Still a cheaper purchase than a crew cab 4x4 Dodge. Everyone wants one so they get high $$ with insane miles -- still. Reg cabs 4x4 are rare and hard to sell.

 

[juddspaintballs]

A 454 3/4 ton would do the job, but it's got the IFS that I'm not very fond of and likely it's going to have a myriad of different little annoyance things that need fixed just like mine, including rusting rear doors. For as often as I honestly tow, I can probably get away with a cheap gasser regular cab 1 ton truck. I don't need to haul the kids around in a new tow vehicle if I'm going to abandon the Suburban so really anything that is up to the task is viable. I'm even considering a 1 ton Sprinter which is rated to tow 10k. My tractor without any implements weighs in around 6500# so adding in trailer weight and an implement or two and I'm right at the 10k weight rating.