Trans slipping after downpipe install

[alphafourwheeldrive]

I have a 97 F 350 and just installed a 4" exhaust. Immediatly after the install, the transmission started upshifting hard. No problems before the exhaust install. It is more noticeable under heavy throttle. Checked fluid level and codes, everything is ok.

[RubberDuck]

I can't remember, but do these trannys have a vaccum modulator on the DP side? If they do, I would bet you a dollar that you knocked that line off. That will cause it to shift hard. But I'm not sure if these trannys have that being electronic controlled and all. Just get under there and look for anything you may have bumped. Heck, Just look everywhere you touched. That doesn't make sense. Unless your tranny was dying and after the install you went out and leaned on it checking out your new mod. Double check everything. I'm sure the auto guru's will be here shortly.

By the way, Welcome to FTE! We're glad you chose us to help you with your problem. I'm certain we can help you get it ironed out. And I look forward to seeing you on the boards.

[tjbeggs]

No vacuum modulator but there is the solenoid pack connector on the DP side. Very good change you knocked that loose or cut a wire. Check that connector and harness close. Also make sure you didn't pinch off one of the trans cooler lines that are over there.

[c00nhunterjoe]

ditto with tj. find the busted wire on the solonoid pack