Tranny problem after using seafoam

[adamp]

So, I used Seafoam on my 92 4.0L explorer. Ran it in through the p/b vacuum line. Did about 1/4pint, let it sit 5min, fired it back up and it smoked a little, but sounded better. Did it again and this time got what seemed like a small backfire through the intake (basically is spit some of the seafoam back out the hose). Engine stalled, but started back up.

Now the tranny doesn't want to shift into gear. I checked the vacuum tree and sure enough one of the hoses had come off. It turned out to be the cruise control, I replaced it, but still no improvement. After I let it cool down, checked under the car and the vacuum line to the modulator on the tranny is on.

So any ideas? If I get the rpms up, it will finally engage, but it doesn't run well and will slip into neutral if I let off the gas. I keep thinking its vacuum related, but I can't find any leaks now. Anyone know if the diapragm could be shot from the "back fire"? any other suggestions? (tranny fluid level is fine).

Thanks,
Adam

 

[peties3]

I would replace the vacuum modulator.

 

[BrooklynBay]

Did you see any ATF in the hose going to the modulator? Try to adjust the bands, and check the fluid level when it is cold, and hot, since the level will change.

 

[Brian_B]

Perhaps the backfire damaged the modulator valve. Its just a rubber baffle (don't know correct term) in there.