98 SE with 3800 NA

I have a strange problem where this vehicle periodically begins shifting hard but levels out after a couple of days. Approximately 103,000 miles.

Some mods as follows: 3" RT downpipe with high flow cat, 2-1/2" catback, Flowmaster super 40's, CAI, L26 UIM, Intense Polyurethane upper motor mounts (front & rear).

I am not setting any codes and have verified this with two different scanners.

Any ideas would be appreciated.

uh-oh....hope your tranny isnt saying bye-bye

Pressure control solenoid. The boost sleeve around it is worn and letting fluid slip by. The PCM sees this as a need for pressure, so it maxes the line pressure to force shifts. It probably only happens after the tranny is warm and stops if you pull over and restart the car, eh?

Have you checked the fluid level?

Good evening.....which fluid level should be checked ? I have the same problem with my shift and I have to overide the shift lock. I was able to see the light in the instrument area (P R N D 3 2 ) and able to remove the key. I noticed my brake fluid is low and don't know if this causes the problem or could be the shift solenoid. I also check the BTSI fuses and it's fine. Anyone have any idea ?

welcome, shpetimq, real clean lookin car ya got. I have no idea about the tranny, but the brake fluid is something that you have to constantly have to check. No the brakes have nothing to do with the tranny, but it could have something to do with loss of stopping power (just messin with ya). why you were able to remove the in anything other than Park, I dunno, but you really should get that looked at.

It'll hammer the planetary gears while doing this too, so watch out, pretty soon you'll be replacing the tranny.