baildvetter000

I have a 98 with automatic. My question is it shifts up 4 times. You are automatically in first gear when you take off and it will upshift 4 times with rpm dropping between each shift. I know I am not crazy because I have the same trans. ( 4L60E) in my 33 Chev. and it only shifts up 3 times. The trans, acts perfect with no slippage and seemingly normal shift points. Any ideas?

Cutlassmaster

When in fourth, your torque converter is locking up as long as certain conditions are met. It will seem like a shift but it is not.
Chris

grantv

Yep, lock-up torque converters have been around for some time now (started in the 80's?). They were made mostly to improve gas mileage; no slippage = lower RPM's once at cruising speed. If you depress the gas pedal a bit when locked up in 4th gear you can feel a slight "down-shift", this is actually the converter unlocking, not you dropping a gear.
I haven't had an auto car (wife's mini-vans only) for about 18-20 years, so if I'm off a bit forgive me.

baildvetter000

I understand the lock up convertor as I have had 2 different vehicles with 700r4s but it does not act that way. As I said before I have a 4l60e in a 33 Chev. coupe out of a 96 Vette ( motor too) and it does not act that way. I can feel the convertor drop when you give it gas but that is not a downshift. This thing will shift 4 times up on any kind of acceleration.

vetteLT193

It is the torque converter locking up. The c5 doesn't have a 700r4 or the later 700r4 which was the 4l60e (that was the electronically controlled 700r4). Believe it or not but different transmissions tend to feel different and the 700 has quite a smooth lockup. The c5 tranny is TOTALLY different. If you don't believe me look under the car and find it. The location should be the first clue