Automatic harsh upshifts.
08-12-2005, 08:11 PM
#1
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Automatic harsh upshifts.
Hey guys,
I drove about 350 miles this evening, on the interstate, and noticed that half way through the trip all of the upshifts are very firm. This has never happened before, the shifts are usually much milder than they are now. It feels like the line pressure in the transmission is maxed out. Is there something obvious I should look for? Thanks for the help.
I drove about 350 miles this evening, on the interstate, and noticed that half way through the trip all of the upshifts are very firm. This has never happened before, the shifts are usually much milder than they are now. It feels like the line pressure in the transmission is maxed out. Is there something obvious I should look for? Thanks for the help.
08-13-2005, 02:43 AM
#4
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Hmmm, full line pressure?
Sounds like the drop resistor went bad.
Could be other things but that's my first guess.
Look here to see where the drop resistor is.
http://jime.homeip.net/DR%20Mod.html
Sounds like the drop resistor went bad.
Could be other things but that's my first guess.
Look here to see where the drop resistor is.
http://jime.homeip.net/DR%20Mod.html
08-13-2005, 06:33 AM
#8
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Join Date: Jun 2005
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I think my car shifts hard to be honest with you guys. I drove a Mustang with the 4r70w tranny, and my car feels like a stick shift compared to that crappy auto tranny. It used to take like a second to shift into gears even when flooring it. A shift kit mod easily got you .2 or .3 seconds on the 1/4mi. The Maxima jsut feels more responsive naturally. When you mean hard shift, do you mean it feels like someone is powershifting?
08-13-2005, 06:59 AM
#9
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The fluid level is good, I service the transmission regularly. The car has 187k. I was wondering about the drop resistor but was not sure how to check it. Any idea's on the best way to do that? Would this send a shadow code, or should the light come on? The check engine light did not and is not on.
08-13-2005, 07:16 AM
#10
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Originally Posted by njmaxseltd
My guess would be 1205 which is line pressure solenoid or circuit fault.
I haven't heard of anyone throwing a code when they do the mod. Activating the mod would be the same as a disconnected/malfunctioning resistor isn't it? So maybe a bad resistor wouldn't throw a code? Unless you've had experience with a bad resistor in the past and a code appeared.
08-13-2005, 10:21 AM
#11
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If I remember correctly, the guys that run the mod that switches the drop resistor out do throw an error code.
It's easy to check it, just remove it from the circuit and measure it with an ohm meter. I think it's value is 12 ohms. Somebody please correct me if I'm wrong.
It's easy to check it, just remove it from the circuit and measure it with an ohm meter. I think it's value is 12 ohms. Somebody please correct me if I'm wrong.
08-13-2005, 10:58 AM
#12
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Originally Posted by njmaxseltd
My guess would be 1205 which is line pressure solenoid or circuit fault.
08-15-2005, 06:26 AM
#14
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The Dropping resistor has Failed!!
That was the problem. I have another one coming from Nissan. Mine was a completely open circuit, no continuity at all. I must admit, I loved the 2-3 and the 3-4 shift, even the lock-up apply for the torque converter clutch was good, but the shift into second felt like the car was going to explode!! My question is, is there a way, besides the wide open throttle mod, to just give the dropping resistor a slight resistance adjustment in order to raise line pressure just a little more? Most automatic transmission shift kits, especially the ones made by Transgo have updates to increase line pressure from the factory spec because most of the newer cars are designed toward comfort rather than shift quality. I've rebuilt and installed shift kits in a lot of domestic transmissions but have little expierience with the one in my own car. I assume that a slight adjustment in the dropping resistor resistance could increase line pressure slightly enough to give you solid, fairly firm shifts for everyday driving. Any thoughts?
08-15-2005, 06:29 AM
#15
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Originally Posted by mbandi
That was the problem. I have another one coming from Nissan. Mine was a completely open circuit, no continuity at all. I must admit, I loved the 2-3 and the 3-4 shift, even the lock-up apply for the torque converter clutch was good, but the shift into second felt like the car was going to explode!! My question is, is there a way, besides the wide open throttle mod, to just give the dropping resistor a slight resistance adjustment in order to raise line pressure just a little more? Most automatic transmission shift kits, especially the ones made by Transgo have updates to increase line pressure from the factory spec because most of the newer cars are designed toward comfort rather than shift quality. I've rebuilt and installed shift kits in a lot of domestic transmissions but have little expierience with the one in my own car. I assume that a slight adjustment in the dropping resistor resistance could increase line pressure slightly enough to give you solid, fairly firm shifts for everyday driving. Any thoughts?
I finally got something right.
08-15-2005, 07:00 AM
#16
Originally Posted by mbandi
That was the problem. I have another one coming from Nissan. Mine was a completely open circuit, no continuity at all. I must admit, I loved the 2-3 and the 3-4 shift, even the lock-up apply for the torque converter clutch was good, but the shift into second felt like the car was going to explode!! My question is, is there a way, besides the wide open throttle mod, to just give the dropping resistor a slight resistance adjustment in order to raise line pressure just a little more? Most automatic transmission shift kits, especially the ones made by Transgo have updates to increase line pressure from the factory spec because most of the newer cars are designed toward comfort rather than shift quality. I've rebuilt and installed shift kits in a lot of domestic transmissions but have little expierience with the one in my own car. I assume that a slight adjustment in the dropping resistor resistance could increase line pressure slightly enough to give you solid, fairly firm shifts for everyday driving. Any thoughts?
Great idea but just doesn't seem to work.
PS I get a 0745 Pressure Solenoid code from the DR Mod. Not always but eventually after a few runs. Sometimes it happens first time I use it.
08-15-2005, 11:25 AM
#18
Originally Posted by mbandi
Thanks Jime, I assumed someone had already tried it. Too bad. Have you used any specific shift kits for your Max with sucess?
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