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Old 12-26-2011, 01:10 PM   #226 (permalink)
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I have some experience in this field and would like to offer an opinion.

From an Ecomodding standpoint, modifying an automatic transmission to allow manual gear selection and control of Torque Converter Clutch operation makes a lot of sense. You should be able to get better economy out of a vehicle equipped with a manual transmission than the same vehicle equipped with an automatic, given the same driving style. The reasons being that with a manual transmission there is no parasitic loss from the hydraulic pump required for an automatic, nor is there any loss from an “open” torque converter. By modifying the automatic the only loss you cannot eliminate is that of the hydraulic pump. You can minimize this loss by keeping your line pressures to a minimum and driving with a “light foot” as much as possible. Manual control allows you to be in the optimum gear for any specific driving condition and have the TCC locked as much of the time as possible. A side benefit of the TCC control is that most of the heat that causes damage in an automatic is produced by heavily loading “open” torque converter. Heat is just wasted fuel. Aside from regular oil changes, keeping the heat down in an automatic is the best thing you can do to preserve it’s life. Another side benefit is that locking the TCC on deceleration makes engine braking more efficient, which in turn extends brake life.

Modern electronically controlled automatic transmissions are relatively complicated, expensive things, and it seems that the newer they are, the more complicated and expensive they get. To the people who have contributed to this thread, that have done some modifications, I take my hat off to you. It takes a lot of nerve to mess with a factory system even if you have a complete knowledge of how it is supposed to work, what the limits are, and how any modifications may affect different functions of the transmission. Having said that, as long as you are very careful with what you are doing, you should minimize the probability of doing any damage. Most of these transmissions operate on the same principals, but there will be differences. I would advise that if you are planning to modify anything, get as much information about your particular transmission as you can get and study it thoroughly before you commit yourself to change anything.

I can only speak of one transmission, the Ford E4OD. I have one in my motorhome, and one in my daily driver. The stock shift scheduling and TCC operation drove me nuts, especially in the motorhome. I’m not a great fan of automatics at the best of times, but converting to manual in either of these vehicles was not a practical option. I had hoped to find an aftermarket transmission controller that I could buy to give me manual control, but at the time (over 7 years ago) I could find nothing, so I built my own. This was a huge job, and I won’t go into details, but briefly, this is how it operates.

With the manual lever in Park, Neutral, Man 2 (2nd gear), Man 1 (1st gear), and Reverse, the transmission operates as stock with the exception that I have TCC control in Man 2. With the lever in Drive, gear selection and TCC control is done with a 4 axis joy stick on the dash. Shifting is sequential, like a motorcycle. Pulse back, shift up, pulse forward, shift down. Pulse left TCC lock, pulse right, TCC unlock. There is no automatic control of gear selection. Line pressure control is automatic and programmable with separate maps for steady state cruise, 1-2 shift, 2-3 shift, 3-4 shift, TCC lock and decel. There are permissives for TCC lock on decel. It must be in a gear that will support engine braking, the throttle must be closed, and the engine above 1200 RPM.

As a side note, both of these vehicles have programmable engine management, so I have a manual switch that will cut the fuel injectors on decel if I wish. This is a great fuel saver in hilly country. The motorhome also has an exhaust brake of my own design (very rare in gas engines) that is of great benefit on steep grades.

These controllers have been in service for over 7 years with no issues of any sort. Since installation, I have never seen the temperatures exceed about 180F. The daily driver has over 240,000 km on it now, so I couldn’t have done too many things wrong.

How did this improve economy, you might ask? Well, to be honest, I really don’t know. With both installations many things were done at the same time so it would be impossible to accurately tell what contributed to what. The daily driver keeps gaining weight. E10 fuel hasn’t helped the mileage on either. The improvements probably aren’t significant, maybe 2 or 3 percent, but any gain is a good gain and the project was fun, even if there is no economic pay back.

If anyone is interested in a stand alone controller for the Ford transmissions, Carl Baumann of Bauman Engineering offers one, or at least I think he still does. It was available when I built mine, but didn’t have some features that I required.

Another more recent entry is the transmission controller from the Megasquirt boys. It was under development when I started but I believe it is available now with applications for the GM transmissions and perhaps others.
'95 Ford E150 4.9L I6 Megasquirt MS1 Custom MSnS Extra
'92 Winnebago Elante 33 RQ Ford 7.5L V8 Megasquirt MS1 Custom MSnS Extra
'93 Bayliner 3288 Twin Ford 5.8L V8s (351 Windsors) converted to tuned port EFI. Megasquirt MS1 Custom MSnS Extra
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The Following 2 Users Say Thank You to E4ODnut For This Useful Post:
abogart (12-26-2011), gone7 (12-10-2012)