About a month ago there was an interesting discussion on this subject (I can't find it though). In it I noted that Trailer Life magazine said the reason manual trannys were rated to tow less is that many people don't know how to work the clutch right and so wear it out prematurely. Someone responded that the auto tranny torque converter is a torque multiplier and thus can supply higher torque on take off. Well I found it in the "Haynes Techbook: Ford Automatic Transmission Overahall" (10355) on page 3-11, regarding the recirculation (actually double circulation) of ATF through the impeller at low engine speed. They say:
"Torque converters are so efficient that, during acceleration from a stop, the torque delivered to the transmission is frequently twice the torque developed by the engine." This means (to me) that a well engineered auto tranny has a built in granny gear effect. Therefore my 3.0 Aerostar which I believe would deliver abour 1600 ft lb at rear wheels by it's 1st gear ratio, probably delivers closer to 3000, which is what the 1st gear in my 5spd manual, 300 inch I6, F150 delivers. Where the f150 will outshine the aerostar in towing is on the highway as it will have far better pulling power at high speed.

 

The standard argument toward automatics is yes there are alot of people who don't know how to drive (automatics). It is also said that they will pull as well or better than a manual. The fuel mileage is (supposed to be) as good or better than manuals, etc, etc, etc...

My argument is and always will be that it is easier to go uphill than down.

It is much easier to go down hill and in control without relying totally on the brakes with a manual trans. I have seen times when pulling my big trailer that I could only make 20 mph going uphill. Using that as a guide I would try to maintain the same gear and road speed going down. With the added benefit of engine braking it is much easier to drop off the side of a hill with confidence and safety. Now if they ever put a Jake Brake on a pickup I MIGHT change my opinion of juice trannys.

Trail Rider

 

I have three tow vehicles two with standards one with an automatic, :
advatages, stop and go traffic, both hands on the wheel,
Dis-advatages, Down hill driving, if I'm in the middle of no-where I can usually duck-tape/bailing wire a manual box to get me home an auto means tow truck.
I personly prefere to tow with the manual box..but to each his/her own

 

 

I drive a Ford F350 tow truck and I prefer the manual trans. Compression braking saves a LOT of wear and tear on brakes and in case of brake failure, I can still slow down. So, in my opinion, a manual trans is safer for heavy towing.

 

18 wheelers....Nuff said. Almost all 18 wheelers are manual transmission. Better range of gear usage and control. Biggest problem with manual towing in a pick-up is that the 1st gear ratio on most light duty transmissions is not low enough. My F250 with granny gear can tow my 6000lb trailer at idle in 1st gear. A M5OD would choke out or burn up the clutch trying to get going.

 

I believe most of the newer Ford auto transmissions use a lower gear set (2.86(1)1.86(2)1.0(3)and 0.86(OD),I think those are close!
The standard manual trans use only a 2.2 or 2.3 first gear ratio( I think).Maybe that's why and as torque convertors do have a torque multiplication factor Ford gives the auto transmission the higher rating.My preference is manual and a heavy duty at that,say the 5 or 6 speed transmission that Ford offers.These transmissions offer a weight saving and do not create the heat associated with auto transmissions.Plus the braking affect of manual transmissions may come in handy at times.

 

The newer electronically controlled 4R100 automatic used on the SuperDuty PSD's have a torque converter clutch that is locked up roughly above 35 MPH.

Add an electronically controlled exhaust brake such as the Western Diesel Turbo Brake and you are in good shape.


2000 Excursion Limited born 11/99 4x4 Toreador Red ext./gray int. 7.3PSD, 3.73LS, Skidplates, Pwr/Htd TeleMirrors, 6CDchanger, HtdBuckets, LT265/75R16D AT, Ford Wraparound deflector, PSDV8 badging, RoofMarkerLights