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Late trans upshifts


ScoobyDoo82

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Well as you might have seen in the Whatever topic I'm taking my GP to a few shops to see if they can diagnose whats up with it. But I wanted to get an opinion here as well...

 

(89 GP, 3.1 440t4)

 

What happens is it feels like the trans shifts late. I REALLY don't think its slipping but I could be wrong. When I accelerate it seems fine but then loses power badly before it finally shifts. I have to rev it to about 3500 for it to shift, and its like that through each gear. I have been trying to Google it and I've found 2 possible solutions. One was replacing the vacuum modulator or possibly a bad TV cable. Has anybody had a similar problem to this? I'd already adjusted the TV cable and it only made a very small difference.

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Make sure you are getting the TV cable nice and tight, push the button in, then push the cone-shaped sheathing as far back into the bracket as you can. After that, slowly press the gas pedal to the floor. You should hear it click a few times. Take a look at the cable after you do this, it should be pretty tight with no slack in it... if there is, then you may need to replace the cable.

 

Do you have any vacuum leaks? Are your HVAC vents working correctly in all positions? Does your cruise control work?

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HVAC only blows through the defrost vents no matter what button I press. And I don't know if the cruise works I haven't tried. As far as I know it doesn't have any vacuum leaks but I haven't tested it or anything.

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you have vac leak. There are three know probelms to cause this issue:

1 Inspect for the presence of the vacuum ball (the mythical ORB of POWAH! ) located under the car below the battery, make sure if present that the line is still attached toe th nipple on that ball.

 

2 inspect the vacuum lines that go from that ball to the junction below the cruise control module an to the inside of the car's body structure inner side of the drivers side of the car. it runs right next to the battery can could have been damaged and broken during a battery installation.

 

3 there is a cheap plastic junction below the cruise control module that sometimes breaks. you can buy a new one(Help! brand products at any auto store) or pocket a good one from any 88-93 W(presumably) at the j/y if needed.

 

inspect and fix that and see what happens?

 

 

 

once that is solved... does the car still do this? probably...

 

check to make sure that the vac line form the intake to the transmission modulator is present. Unhook the vac line at the modulator and turn the nipple face down. if fluid comes out the modulator is bad... but it should only affect first to second gear, iirc.

 

finally, let me ask... have you ever serviced the transmission? if not, do so. if so do so again???

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Well sir you certainly helped. I found 2 vacuum hoses that were broken and now the hvac works properly. The cruise is still MIA though. I adjusted the TV cable one more time and I got some results. First gear to second gear is much quicker and smoother... however it feels like it slips back into first or something. I made a video that might help...

 

(Don't worry about the check engine light... when I checked the vacuum modulator I forgot to plug the IAT sensor back in, thats all it is)

 

Every time I accelerate in the vid its a smooth steady acceleration, so when you see the RPMs spike its not me jabbing the gas. When they do spike is when the car feels like it falls on its face.

 

[video=youtube;EMMDF87Xan0]

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Did you ever CHECK the modulator for a ruptured diaphragm? Pull off the hose at the modulator, if there's any ATF present, the modulator is shot.

 

While you have the hose off, run the engine and assure that there's proper vacuum TO the modulator.

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  • 2 weeks later...
HAVE YOU SERVICED TRANSMISSION? could be low line pressure from a dirty trans filter...

seeing this come up in the whatever thread...

 

:facepalm:

 

do a pan drop. I personally have a siphon kit to extract fluids, and predrain the tranny before servicing it. If you do not, you can still just drop the pan and use a large catch pan. install the pan with a new filter and top it off. if that makes things better, probelm solved. and... DO NOT HAVE A "FORCED' FLUSH done. You need to get a new filter in there, and share what you find on your magnet, for instance....

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