I was driving at a speed of 70mph when suddenly my cars tackometer winded out and my car was no longer in any gear.i had no prior warning or signs of trouble as of now my car will only stay in gear up to 3mph /no reverse

I think you could use this manual method instead.. My nephew use it to repair my car and it's totally repaired now. Here's the website he bought it from. reliable-store

There are forks in the transmission that shift from different gears. They break and wear out. Bears will also cause a symptom like this, but they will make noise.

The shift solenoids may not be getting the correct signals from the transmission control module . Read the codes to see if it's the solenoids or the module.

Clutch/pressure plate are most likely worn and slipping.

Your best bet , take it to a transmission shop or the dealer . Rebuild transmission . There is no belt inside the transmission .

indicates that the torque converter clutch servo/ solenoid has lost the electronic controls
could be a wiring/ connection problem in the harness , or a TCM problem
run the fault codes to see what shows up

The only way to accomplish that is to change the axle gear ratio. Trucks are generally geared for hauling, towing, plowing, etc, so you have more torque and power at lower speeds. If you change the axle ratio,your low end performance will probably suffer (sluggish acceleration at low speed). Basically, your T100 is not designed for 70mph highway driving.

sounds like the vac control valve or the kick start cable is fitted right ,but then you did have the rolls royce of auto boxes in as original ,a c4 which should be about 3000rpm for 70mph ,depending on the final drive ratio fitted to your car

How many gears does your car have? One of my cars has to do a little over 3000rpm to maintain 70-75 in 5th gear. My other car has to do about 3000rpm to maintain 65-70 in 5th gear.

It all depends on the number of gears your car has and the gearing ratio. The second car I have is geared more optimally for city driving and gets better fuel economy going slower than fast highway speeds.

Having driven several rental cars too I would say anywhere between 2500 to 3000 is reasonable for the average car. If you are driving a vehicle like say a porsche, bmw or audi they may have more gears and may be at a lower rpm at 70mph than your car.

Pull out the spark plugs one at a time and check to see if they are firing. I had the same problem while merrily driving at 70mph. All of a sudden I lost spark in one spark plug wire. It just went without warning.