Hard Shift


Old 04-30-07, 06:13 AM
Thread Starter
Join Date: Mar 2002
Location: kentucky
Posts: 267
Hard Shift

Good Morning, the last couple of days my 91 Ford F150 XLT Lariot, 302 V8, Automatic trans w/Electric O/D button on dash, has started to do a not so smooth up shift from 1st to 2nd to 3rd. It goes into O/D smooth. It is a solid shift with a slight jerk. I can manualy shift it and the shift is smooth. The down shift is smooth. Can anyone give me some advise. Thank you in advance.
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Old 04-30-07, 06:22 PM
Join Date: Jan 2007
Posts: 81
I do not know if this applies to your truck but here goes. I had a 1 ton that would do the same thing at times. What it turned out to be was that the trany would go into tow mode and shift at a little higher RPM and lock in to the gear harder. You would really notice it when going from 1st to 2nd. Ask about it at the Ford service department in your area.
Old 05-01-07, 03:28 AM
Join Date: Mar 2007
Posts: 202
Talking Tranny shifts hard

Granted I am old school, but as I remember there was a Modulator on the tranny than ran off of vacuum from the intake for shifting. They have a diaphram inside that can bust and cause shifting problems. They will spew white smoke usually when they bust. Also, they could be adjusted to shift faster or slower.

Last edited by NewHomeowner396; 05-01-07 at 03:29 AM. Reason: mispell
Old 05-01-07, 07:29 AM
Thread Starter
Join Date: Mar 2002
Location: kentucky
Posts: 267

Thank you all for your suggestions. I have looked at the trans and could not find anything that looked like a vaccum operated modulator. I am enclosing photos of what appears to be an electronic device of some sort. Could this be a modulator. What are your thoughts?


Old 10-10-07, 09:10 AM
Michael's Avatar
Join Date: Nov 2005
Posts: 56
Hard shift

If that trans is an E4OD the hard shift is related to the MLPS mounted on drivers side of the tranny. There are TSBs about this at alldata. Replace the MLPS and the problem should be fixed.

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