Here's some food  for thought though

GM 6 Speed automatics. These are heavy duty TurboHydro 400 transmissions with an overdrive that can be engaged in each gear. When we get Warranty, GVW rating, and other information we will post it here.

Chrysler Automatic Overdrives.  There are heavy duty units rated up to 25,000 GVW. 

Ford Automatic Overdrives. There are a lot of options for Ford.

Transmission Adapters. There are adapters so you can use one manufacturers transmission with another manufacturers engine. This sounds good but make sure you research how you are going to get the shift linkage to work. 

Manual Overdrives. The tried and true add ons to your existing transmission are from US Gear and Gear Vendors. These units just bolt on to the back of the transmission and you shorten the drive shaft if necessary. They have the advantage of simple installation and can be engaged in every gear or left engaged all the time until you need the lower gear ratios. The disadvantage is they have to to manually shifted. Some drivers are not comfortable having both an `automatic' and a `manual' transmission at the same time. Even if both you and your wife get used to it, what happens on a trip when one of the kids or grandma may be driving.

Torque converters. -- There are lots of options and it is an interesting situation. In some situations you want the torque converter to `slip' so it acts as a torque multiplier. This is particularly true when starting from a dead stop or pulling a steep grade. The problem is that this produces a lot of heat and lowers fuel economy. Then at cruise speed you want the torque converter to `lock up' to minimize engine RPM and fuel consumption. The `lock up' torque converters are a fairly recent innovation brought on by the push for fuel economy and typically require `computers'. There were some torque converters that locked up mechanically. For example in the late 1970s Chrysler had both a lock-up and non-lock-up version of the 727. The transmissions/torque converters were almost identical and the only way to tell the difference is to open them up. The lock-up version was used in passenger cars and small trucks. The 1-ton van bodies used for many class-c motor homes and the heavier trucks typically had the non-lock-up version, apparently because the EPA mileage requirements did not apply to these units. Replacing your transmission and want better mileage? Look for the lock-up version if available. The differences are internal and the only difference you will notice is about 500 RPM drop at cruise speed, less heat at cruise speed, and some fuel mileage improvement.

Computer operated Transmissions. -- There are some after market computers that will help you install a new technology transmission in an older unit. They are even programmable by hooking them to a desktop computer running Windows so you can set shift points etc. They are available for Ford products,  a prototype unit for Chevrolet products is in test and depending upon demand a Chrysler product may be forthcoming.

This is a work in progress so please bear with us while we do the research and keep the site up to date.

We ask that you double check the information with other sources to insure accuracy.

you can reach us at emeryk@eksco.net for comments/suggestions