Harsh down shift, or wompy motor?
Thread Starter
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Tuned
Joined: Aug 2004
Posts: 311
Likes: 4
From: Omaha, NE
Harsh down shift, or wompy motor?
87 E-150, 300 w/C6
While driving at moderate speeds (25-60) runs pretty good, have some lifter rattle but not worried about it. Sometimes, not all the time, when I let off the throttle it will coast just fine for a sec, then harshly down shift into what seems to be first. The van will continue to decelerate until idle speeds, I would guess (never had the traffic to see if it got down that far).
I understand that downshifting is part of the automatic transmission and all that, but when it does it at 60+, I don't know if that's good. Pretty sure I have some vacuum problems, shifts really hard into D and R. Would my downshifting possibly be a vacuum issue?
While driving at moderate speeds (25-60) runs pretty good, have some lifter rattle but not worried about it. Sometimes, not all the time, when I let off the throttle it will coast just fine for a sec, then harshly down shift into what seems to be first. The van will continue to decelerate until idle speeds, I would guess (never had the traffic to see if it got down that far).
I understand that downshifting is part of the automatic transmission and all that, but when it does it at 60+, I don't know if that's good. Pretty sure I have some vacuum problems, shifts really hard into D and R. Would my downshifting possibly be a vacuum issue?
Cargo Master
Joined: Oct 2004
Posts: 2,148
Likes: 0
From: Seneca, SC
could easily be one. The vacuum tells the tranny how hard you're pushing the gas. If it's not there, then the only thing the tranny can use is the speed you're goin. @60+ you're probly shifting into second. Otherwise you'd be saying that you need a new engine, as your old one spun apart.
Replacing that main vacuum line will probly fix your problem.
Replacing that main vacuum line will probly fix your problem.
Thread Starter
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Tuned
Joined: Aug 2004
Posts: 311
Likes: 4
From: Omaha, NE
Hmm, thanks. Wil have to crawl under there once the weather gets nice again.
On another note, note sure if it is related. Was out "rompin" the other night and after doing some cookies in a gravel parking lot i went to leave, and the sucker shifted in neutral. Mashed on the gas and went nowhere. Had to shift into neutral, then back into drive to get it to pop back into gear.
On another note, note sure if it is related. Was out "rompin" the other night and after doing some cookies in a gravel parking lot i went to leave, and the sucker shifted in neutral. Mashed on the gas and went nowhere. Had to shift into neutral, then back into drive to get it to pop back into gear.
Cargo Master
Joined: Oct 2004
Posts: 2,148
Likes: 0
From: Seneca, SC
that might be loose linkage. a buddy of mine's dad had an old beater that did the same thing. Getting on it flexed the linkage a little and it slipped into the wrong gear. I don't think they're related, but if the vacuum fix dosen't fix the shifting, then I'm wrong and there's a little more work in your future.
