[Black97Tbird]

I have a '97 Tbird with a 4.6 and no modifications. I have noticed lately that my tranny shifts roughly when going up a grade at low speed. I have had the tranny fluid changed, the computer reprogrammed, and the 1-2 accumulator piston changed (just for general principles); and still have the problem. The problem occurs when I am driving along at low speed and start up a grade. The car will be going about 35 mph at 1000-1100 rpm (4th gear) on the level, then try to downshift once going up the grade. When it downshifts, it doesn't shift smoothly and seems to hesitate. I noticed the problem when I picked the car up at the dealership after they replaced the plastic intake manifold. The battery had been disconnected during the intake replacement.

The tranny doesn't have any problem shifting under acceleration.

Has anyone else noticed this issue?
Is it something I should be worried about and can it be fixed (without rebuilding the tranny)?
Once the computer re-learns the parameters will the problem go away (it has been 3 weeks and the problem still exists)?
Should I just turn off O/D around town and on hills (I live in western PA so I'll be turning it on/off a couple of times everytime I drive anywhere, which will get annoying quickly).
Would a chip help, since it would increase the shift points?
Why does it shift into 4th so early at low speeds (100 yeards out of my driveway @ 30 mph it is in 4th)?

Any suggestions would be appreciated.

 

[pgirolam]

Are you receiveing shudder when you step on the gas?

 

[White Lightning]

Yes to a chip! At least on accel, it will keep it from shifting up so soon. Once it is OD, however, unless you hit the gas hard, it stays in OD to around 38 mph.
You should always have the OD off in hilly terrain, esp. when your finding it is doing what you are saying. That saves excessive shifting, wear, and heat. I don't turn on the OD until I am on the highway. As soon as I hit stop and go traffic, it is off.
Get a trans cooler on there as soon as possible, flush and refill with Mercon V if you haven't already. That and the chip will keep your transmission and you smiling for a long time. If you really want to smile, do the shift mods!

Just my $.02
Scott

 

[pgirolam]

I got the trans service at 75k (I now have 92k). My service was done at the local Ford Dealership, I'm assuming that they would use Mercon V... Is this a bad assumption?

I noticed that there are several posts for "shudder" and that there are some tech service bullitens.

I get shudder between 35-40 when car is in 3rd and 65-70 just before transmission has to go from ovd to 3rd.

With a TSB number in hand, I wonder what the Local Ford Service will do for me. (probably nothing)...

pg