I know that some of you remember the hydro-matic transmission that was used on the early '60s oldsmobiles, cadilacs and pontiacs. These transmissions would lock up immediately upon shifting and would stay there (locked) untill more gas would force a gear change or it shifted into the the next higher gear. It was like having a standard transmission that shifted automatically. This was a great transmission and I always thought that as soon as I got old enough, I would buy a vehicle with that typw of transmission. It never happened.

I have an '03 FX4 with automatic transmission and I would like to make the lockup stay "on" all the way through the gear. In other words I want it to lock up when it shifts to the next gear and stay locked until the next shift. I've tried "shift kits" but they just make the shifts harsh.

Any body know how I can make this happen?

 

In the tranny shop I worked in, it was called a Slim Jim. This was 1969-1970.

 

I have an 02 FX4 and I've had the trans beefed with a shift kit for firmness. For locking up I got a tuner with a program that allows me to change the factory programming to what I want. I also set it up to work with the 4.88 gears and stock tires.

 

So if I get a tuner I can program the trans to lock-up and stay locked up until I mash the excellerator say 2/3rds throttle or so? How do I get it to mimic the "slim Jim"

 

If you get a SCT X3 the dealer can write tunes for you. You get 6 with it. 3 generic tunes and 3 custom tunes. Just tell the dealer what you wish to accomplish. I don't think you want to write your own tunes.

 

Thanks Kaboom, I did a little research and found this info on the programable specs for the SCT tuner SHIFT ADJUSTMENT Automatic Transmission Shift Schedule:
WOT 1st - 2nd: -3 to +7mph
WOT 2nd - 3rd: -4 to +8mph
WOT 3rd - 4th: -5 to +10mph
WOT 4th - 5th: -5 to +10mph

In english, what does this mean?

 

It appears to be the table you select shift points from. SCT allows you to change values in certain systems such as spark, fuel and transmission. Those are the different amounts you can change the WOT shift points.