Shifting problems

I have a 2000 auto rodeo ls that is shifting oddly. I have cleaned the contacts on the range sensor and lubed the slip joint on the two piece driveshaft. When I start out everything shifts ok then gets progessively worse. If I floor it the first two gear changes feel like it over revs then slams into the next gear. If I accelerate cautiously the strange shifting is not noticeable, then after a half hour of driving it is only slighlty noticeable (thats having a light foot). When I get home I will back up into the driveway and I will alternate between drive, and reverse and I get mild clunking.
I took it to the dealership to have the fluid and the shift points checked. No codes, shift points ok and fluid is a medium colour(half life) and at full level.

I am hoping u-joints. Anybody have any ideas.


John

If you have 25k on the fluid, have it flushed.

other possiblities, could be bad ground to the alt. Weak battery. dirty grounds .....

I had some tranny troubles that was partially related to a bad intake manafold gasket. And after a flush it was gone.

I had some tranny troubles that was partially related to a bad intake manafold gasket. And after a flush it was gone.


Thats weird I just had my intake manifold gasket replace in Dec. I will get it flushed tommorrow. Dealer wanted 200 bucks. I will get it done elsewhere for a 100. I have about 25 000 kms not miles .

John

Just had the tranny flushed and no improvement. One thing I noticed is that I tried to start the car in neutral and it wouldn't start. I thought you could start an auto in neutral. Maybe my range sensor is finished.

John

this is about the only other thing that comes to mind:

http://www.automotiveforums.com/vbulletin/showthread.php?t=320620&highlight=start+park

Just had the tranny flushed and no improvement. One thing I noticed is that I tried to start the car in neutral and it wouldn't start. I thought you could start an auto in neutral. Maybe my range sensor is finished.

John

To update my problem I ordered a new range/mode sensor/park neutral/inhibitor switch from St. Charles. The rodeo starts in neutral now but I am still having hard shifting. I had it flushed and no improvement and no codes.

It seems like an electrical problem. It all became noticeable after I had the img replaced. The guys at the dealership sold me some fuel treatment to cure my fuel sending unit. They said it would not harm my car. What I did have was a misfire code that came as fast as it went away. I have ordered new spark plugs from sparkplug.com. The originals were cleaned in July and put back in. I'm thinking that the fuel treatment may have pushed the plugs over the limit and are sucking up a lot of voltage from the system (I read that from an Auto tap link about sparkplugs) The plugs have 60000 miles on them now. The guy at the dealership said that weak plugs can screw up the system and not throw a code.

The most noticeable thing was if we had a deep freeze
(-23 C,-9.4 F), the car would start but when you put it in gear the transmission would not engage, then after a few minutes the it would kick in.

I have checked the voltage of the battery with my digital tester and the battery shows 12+ volts cold, 14+ volts upon start up and 13.8 volts after a half hours worth of driving. I am going to have the battery load tested tommorrow.
After that I've got to find the alternator ground and clean it.

Would spilt coffee on the shifter seep onto any contacts below? I have only spilt a few drops that I clean up.

Does anybody have any other ideas

Thanks

John