02 Limited Trans replacement headaches

[mhamric]

Wondering if anyone else has had these headaches. I have an '02 Limited 4.6L 4x4 that had the infamous diesel sounding transmission/torque converter. It was getting louder and starting to slip a little so I decided it was time to have it replaced. Went to one of the best shops in town who only do transmissions. They pulled it out and put in a rebuilt one, they told me it's of newer technology using a single clutch plate instead of a dual one or something like that. They said it completely eliminates the chance of the torque converter going bad again and sounding like a diesel. Unfortunately, now once I get over 35mph, whether Over Drive is on or not, the torque converter is turning on if I try to maintain the current speed. Basically, if I'm driving down a flat road and I'm going 40mph, I let off the gas to coast a little then I just slightly touch it the torque convert jumps the RPM's up 700-1000 over what it originally was, then drops it back down a second later. It feels like it's downshifting, but it's just the torque converter shooting to 100% and then dropping off to nothing a second later. The shop is convinced that the PCM needs an update. Thankfully, I was able to have the owner of the shop ride along with me with his computer hooked up to it and experience it. Anyone else have any ideas? I've heard from other places that it could be a bad solenoid pack...

Thanks,
Mark

 

[mhamric]

Just got her back from the trans shop, they updated the PCM and no change. So now they say it's the new lockup valve that is larger than the original and that's what is causing the 'firmer' shifts. They're going to swap it back to the original size and they say that should reduce the firmer shifts back to normal. Hopefully, it'll be resolved Thursday when I drop it back off...

 

[imp]

..... Basically, if I'm driving down a flat road and I'm going 40mph, I let off the gas to coast a little then I just slightly touch it the torque convert jumps the RPM's up 700-1000 over what it originally was, then drops it back down a second later.Thanks,
Mark

When you get off the gas pedal, the torque conveerter clutch releases, or unlocks, thereby making the TC operational again. Bringing the gas pedal back into play quickly brings rpms up suddenly, as TC spins faster than transmission itself (normal), then engages, or locks, the clutch, taking the TC out of the picture again.

Try bringing rpms up slowly after releasing the gas pedal, while watching the tachometer, and the engine will increase speed smoothly up until the clutch engages, with no engine overspeed or "jerk". If that does not work, something else is wrong. imp

 

[mhamric]

I tried that and so did the shop. They talked with someone who's very familiar with these transmissions, I'm guessing they finally called a dealership. They said that most people don't notice or don't care that much about the 'firmer' shifting. But some people like me who unfortunately and fortunately notice small changes with their vehicles, then they have to do some extra work.

They are going to change out the lockup valve which was made larger with the newer transmission and put one in that matches up with the original. I'll know more after Thursday.

 

[mhamric]

Here's an update:

Trans shop had another '02 getting it's failing trans replaced...go figure...they put a trans in it that was correct for it's year with the double clutch in the torque converter and presto, no problems at all. No crazy shifts, no torque converter jumping all over the place. Works like you would expect it to work. So a week from tomorrow they'll do the same for mine as the lock up valve change didn't do much of anything.

Mark