ok ive been having huge problems with my car. It was hitting 4200 then just dying, kind of like bouncing off a rev limiter. Had it professionally tuned and all and they could not find whats wrong with it. Well i had the transmission flushed at jiffy lube and found out they put in Mercon and not Mercon V. Immediatley had it flushed at Ford and now it doesn't do that. Now what it does at WOT is rev all the way to 5000 rpm and not shift. However when i take overdrive off and punch it, it pulls and works fine. So basically it seems that when i floor it when in over drive it does not shift but without it, it does. What does this sound like?
tranny probs?
- Thread starter sanitarium16
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Without getting into the mechanical functions, look at the obvious and work to more complex items. First, make sure the trans is warmed up enough for the shift into overdrive to occur. My truck will not shift in to overdrive until the temp is correct. Also you had the transmission fluid changed twice, is the fluid level proper. Without knowing the vehicle model etc. it is hard to point you to a sensor that may be a problem.
Also the vehicle and engine and trans type would help. Ford helps, but which one.
Also the vehicle and engine and trans type would help. Ford helps, but which one.
its a 98 mustang with the 4r70w transmission. The level is good and i did do it when it was fully warmed up. this thing is driving me crazy!
Did you change the rear-end gears on this one? I saw another post on here with almost the same exact symptoms and they had changed the rear-end gear.
Yes, i did change the rear gears from 3.08 to 3.73. They put in the speedogear and everything with that is fine. The check engine light, isnt on and there is no codes in the computer, i checked. The car seems to be stuck in third when i floor it and it has the problem. I don't drive the car too hard and i always keep up with maintenence.
Did you ever get the chip to recalibrate the computer for the new gears?
yes i had it dyno tuned and it exhibited the same problem. Everyone is stumped!!!!
JHZR2
Staff member
problem 1) service at jiffy lube
problem 2) driving the car too hard - do you have any indication that the trans, engine OIL (not water temp on the gauge), etc is up to correct operating temperature?
the OD issue sounds electronic to me...
JMH
problem 2) driving the car too hard - do you have any indication that the trans, engine OIL (not water temp on the gauge), etc is up to correct operating temperature?
the OD issue sounds electronic to me...
JMH
1st step- Pull codes. If you have a code it will at least be a starting point for further diagnosis. You do not have to have a "CK ENG" light on to have a stored code.
If you can get access to a scanner, select the "MLP" sensor and find out what gear is indicated when in "D". I have had much weirdness caused by MLP sensors and they don't set codes except in rare cases. If you have the time and a lift, verify nothing has hit the MLP sensor. Unplug the MLP harness, check for water intrusion. On the passenger side of the trans check the main connector for the same, verify wire harness is not chafed.
Oddball problem but you have to start somewhere. I wish you luck with it.
If you can get access to a scanner, select the "MLP" sensor and find out what gear is indicated when in "D". I have had much weirdness caused by MLP sensors and they don't set codes except in rare cases. If you have the time and a lift, verify nothing has hit the MLP sensor. Unplug the MLP harness, check for water intrusion. On the passenger side of the trans check the main connector for the same, verify wire harness is not chafed.
Oddball problem but you have to start somewhere. I wish you luck with it.
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