towing capacities for automatic non lockup
 

Hi all,
New to the forum. I have owned a second gen 12v before with a 5spd and loved it, but embarking on a project....I want to build a tow rig for our race car. We race out at Bonneville so its a 1500mile trek every year towing a 10,000lb trailer on the hwy most of the time. Other than that it will be used for usual work towing normal cars or unloaded. I want to build a 12v powered suburban. I have a 1969 Chevy 3 door suburban that would be the perfect vehicle with a Cummins. I have a couple choices. I have a wrecked '92 3/4ton with auto, but I dont know the history of other than its a pretty nice truck . Next a buddy has a '92 1ton that he has replaced just about everything on it from new AC to injection pump, tranny, rear axle etc etc...but its auto as well. he wants 3k for the 1 ton. My main question is how well will the non-lockup converter handle towing the heavy race trailer...I can add a secondary cooler with fan to help cool it. I would turn up the motor a bit, but just a fuel pin, cold air, good exh and minor adjustments, so not crazy power, just want to cruise with the trailer at 80mph but get decent milage as well....both have 270k or so on them. Right now the suburban is sitting on a late 70s K20 frame, but would just run it as 2wd. If I use the drivetrain from the 3/4 ton, ill just swap over the motor/trans/rearend....if going with the 1 ton donor, I might see if I can just drop the suburban body right on the one ton frame and run single wheels in the rear or custom make some fenders for dualls...but it will always be a bumper pull, so the dual wheels really arent needed....

any tips or suggestions much appreciated?

Hans

I tow a 13k fifth wheel and until recently ran a 518 auto in my truck. Along with tweaking the pump, BHAF and 4in.exhaust I would recommend a TransGo TFOD kit and a good convertor (SunCoast, etc.) as well as the extra cooler for the tranny. Don't forget the 3200 spring and you will want to upgrade your turbo both to keep EGT's down and for quicker spooling and responce. Getting the 14cm exhaust housing and the 60mm compressor upgrade will work very well for you. Just my $.02 based on experience with my truck, Good Luck with your project!!

Why not install an NV4500 5 speed while doing the conversion?

thanks for the comments guys. Yeah, I would love a manual, and of course way better to do it now than later, just a cost thing I guess. I havent researched the swap, but I remember that a 5spd from a early 2nd gen(NV4500) will bolt right up? I need the adapter plate as well if I remember correctly....what about flywheel? If I get a trans from adapter plate with flywheel, cllutch and all will it bolt right up? If I can find one in teh Houston area that isnt outrageuos, its an option....

and to show my newbiness...whats BHAF?

Hans

Sorry man its a Big Honkin Air Filter, NAPA 2790 or the like. I think you would need the second gen flywheel as well but someone who has done that swap can chime in. You would think you wouldn't have trouble finding stuff in the greater Houston area but when I wanted to swap in a 47RH so I'd have a lockup converter, I searched for months and couldn't find one so good luck !

It doesn't just have to be an early 2nd gen(NV4500). They'll all work. Just make sure it's from a Dodge and not a Chevy. The Chevy's tend to be cheaper but it won't bolt up to the Cummins without an expensive adapter.

If you keep your truck for a long time, the cost savings from a manual will probably pay off. You'll get better fuel economy and enjoy better dependability. This if it this way, pay now and save later.

Anyways, Cummins into Suburban equals awesome conversion. I've got one myself and couldn't be happier.