Matthew Currie
NAXJA Member #760
- Location
- Vermont, land of big clay
jeepdude10000 said:
It's supposed to lock up in the top two gears. It's possible that it's locking in second and shifting locked. It's been some years since I had an automatic, but when I had my 87 AW4, it appeared that in OD it would shift from third to fourth without unlocking if you didn't push it too hard. Accelerating harder it would wait to lock until it was in fourth, and if you counted the shifts it would feel as if it had 5 speeds. Mine did not have a tachometer, so it was hard to judge exactly what happened when. Shifts were so smooth and seamless it was hard to keep track of them. My stepson had an automatic with a tach, but I never got a chance to play with it much (except of course when it was broken, then it was all mine...). If you have a tachometer, you might be able to distinguish locked from unlocked by how much the tach needle rises when you accelerate. If you do it hard enough to unlock (or if it's not locking at all), the needle will jump and then settle back. If it stays locked it should rise gradually and not drop back.
I don't think there's any disadvantage to locking up, except that unlocked you'll get a little more torque multiplication. I could see wanting it unlocked when wheeling. But theoretically, at least, it should run cooler with the TC locked, since there's no slippage in the TC. I think one of the main reasons for recommending downshifting under severe loads is to prevent it from continually unlocking and relocking under stress. Then again, automatic transmissions are kind of funny, and if some expert told me that it should run cooler with the TC unlocked, I'd say OK, just another one of those automatic anomalies. Anyway, if yours seems to be behaving, it's probably all right. They're pretty bombproof.
