Re: 727 to 518 swap...

[farna@xxxxxxx]

Maybe I was being a bit to simplistic. I meant keeping the engine in a power producing rpm band more than speed. If you drop below the good torque band of an engine you lose speed and power, so speed and rpm sort of go hand in hand, along with gearing. If you can tow a load and maintain 50 mph or so in OD, you sould have the engine in its power band. Drop much below that (depends on vehicle!) and rpms are to low in OD to stay in the power band. If you have the power to maintain 50 or so going up a hill, it shouldn't strain OD to much. Now I'm sure there's a limit to this, especially if using something like a Power Stroke diesel engine, which could maintain rpms in the power band and still have a load heavy enough to strain the OD gears. It depends on the "smarts" of the transmission some too. I have no problem pulling a 3,500 pound trailer with my Volvo 960 (2.9L DOHC in-line six), and I left it in OD. It didn't run in OD more than half the time -- it would quickly drop to 3!
 rd whenever there was much strain on the drivetrain, not just a drop in speed. The older, non-computer OD trannys don't do as well. The computer monitors engine rpm as well as road speed and reacts faster. The AW4 does almost as well, but the Volvo drops out of OD a lot quicker than any Jeep I've driven -- but that could be programming due to engine size (Jeep 4.0L). 

I towed a 65 Classic hardtop (V-8) with my five speed Comanche back about 8 years ago. It never went into fifth gear! I got some looks too -- the trailer and car combo had to outweight that truck. Wouldn't have done it if the trailer didn't have brakes (surge brakes) though! Makes a world of difference!! 

On July 19, 2005 Mark Price wrote:

> So, If you go faster you can tow in overdirve and that puts less strain on the unit??? I'm sorry, I'm not buying that one!
> The only time I put my overdive transmissions in overdrive when towing is when I go down hill and don't need engine braking.
> I will also use overdirve if simply pulling an empty dolly or utility trailer. I'd rather buy a few more gallons of fuel then a transmission!
>   I've towed things I shouldn't have with vehicles to small for the load and always done so successfully. Just by being very mechanically aware of exactly what was going on and what to do and more importantly what not to do!
> Maybe I was pushing my luck with the 4 hour tow back from Columbus Ohio with my 65 Ambassaodr convertible on a dolly, backwards with it's top down! Behind my 96 Cherokee Sport. Boy did I get some looks that day!
> 
> YMMV
> Mark Price
> mpriceATwestco.net
> Morgantown, WV
> 69 AMC rambler, 4.0L, EFI, 5 speed
> 65 Ambassador Conv, 327 AUTO, Basketcase
> 01 S-10 CREWCRAP 4X4
> 
> 
> 
> ---------- Original Message ----------------------------------
> From: farna@xxxxxxx
> Reply-To: mail-From-mprice-westco.net@xxxxxxxxxxxx
> Date:  Tue, 19 Jul 2005 09:29:45 -0400
> 
> >You CAN, however, tow in OD IF you keep the rpm up. That limits to relatively flat land towing light to medium loads at 55+ mph for most. For heavy loads, like pulling most cars on a trailer, no way! If you have a good cooler you can tow more, but it does put a strain on the OD gears. Average Joe barely knows where to put oil and water in a car, much less how to drive and actually have to think about conditions and what gear to use! What use is an auto trans if you have to think about how you're using it?? ;>
> >
> >But you can use a BW OD, remember! It can be remote mounted behind an auto with a bit of work. A coupler and front cover plate has to be fabbed, as well as a cross member (the easy part). Then the wiring figured out -- also not terribly difficult. I've seen a couple done this way in the past, though haven't done one myself.
> >
> >The 327 has 9.7:1 compression. If you go strictly LPG you will want to boost that to around 11:1.
> >


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