My Transmission has a mind of its own
#1
03-25-09, 03:41 PM
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My Transmission has a mind of its own
Hey all, Got a 90 Ford Ranger 2.9 liter, 4-speed automatic (3-speed w/overdrive) Checked vacuum going to modulator, fluid slightly discolored (brownish) but not burnt, fluid level good.When I start out in the A.M. for work, it will not upshift from 2nd to 3rd unless I pull er down into 2nd manually, It then shifts to 3rd. I then shift up into drive and it seems to be fine. At 55mph I slide it into O.D. and for the rest of my morning commute it will upshift and downshift fine after that.I let it warm up good.Ive also tried just leaving it in Drive, doing its own thing and after a few minutes of driving slow, letting off the throttle from time to time, it seems to begin to shift. Something seems to be sticking.Should I get it flushed & new filter installed ? Do I need to try a new mod valve also ? Or does it sound like to you Trans-Specialists like I need to Get er rebuilt? Only 80,000 on this rust free, clean little gem. Thanks for any words of wisdom folks.
Last edited by mowermonkey; 03-25-09 at 05:03 PM.
#3
03-25-09, 04:12 PM
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Should I get it flushed & new filter installed ?.........
ABSOLUTELY NOT..............!!!!!!!!!!!!!!!!!!!!!!!
What you are experiencing is "Internal " leakage. The fluid must build up pressure inside of a "Drum" and In laymans terms, When the pressure becomes excessive, or drops below a predetermined point, the "Shift" occurs.
This pressure becomes erratic when the drum and pistons dont "Seal " anymore. Its worse in cold weather, and before the car warms up, because of the "Thickness" of the fluid, and the time involved to fill the "Drums" to Working "Volumes". Flushing will only remove the Sediment and debris that has Neatly packed itself in the nooks and crannies, and will likely make your condition worse.
ABSOLUTELY NOT..............!!!!!!!!!!!!!!!!!!!!!!!
What you are experiencing is "Internal " leakage. The fluid must build up pressure inside of a "Drum" and In laymans terms, When the pressure becomes excessive, or drops below a predetermined point, the "Shift" occurs.
This pressure becomes erratic when the drum and pistons dont "Seal " anymore. Its worse in cold weather, and before the car warms up, because of the "Thickness" of the fluid, and the time involved to fill the "Drums" to Working "Volumes". Flushing will only remove the Sediment and debris that has Neatly packed itself in the nooks and crannies, and will likely make your condition worse.
#4
03-25-09, 05:01 PM
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It just started doing this earlier in the last week, We had a couple of fairly warm days where it was not as noticable. Thanks
#5
03-25-09, 05:28 PM
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Originally Posted by the_tow_guy
Did it also do it during the warm weather? [I'm assuming it's still pretty chilly up there].
#6
03-28-09, 03:40 PM
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Fine Tuning the A4LD Transmission
Well despite recommendations I did the flush on the Trans. Also installed a new vacuum modulator. Shifting much better now. Does any one know what the screw head is in the vacuum port on the modulator? Ive been using a small flathead which seems to work but doesnt feel right. Thanks guys. Next step is to adjust the bands and hope to get another 1000K on it.
