ttruex

Just curious what any of you see at highway speed in D. I'm thinking I'm not getting the torque convertor to lock up, as the RPMs seem high. At 55MPH, I see about 2k RPM, at 80 MPH, I see 2750 RPM. This seems high for a V8.

I just did a tranny fluid and filter swap, which eliminated the shift shudder I was experiencing, but I'm wondering if there's more to chase. Does the TC lock up and drop revs at higher speeds?

5 spd automatic, BTW. 2004 E500 4matic wagon.

ttruex

C'mon, Man, 88 people have looked at this, yet no one can glance down at their tach whilst cruising the highway and give me a RPM?

Michael.Sinz

2004 E500 - 7spd - ~1600 at 60.

Hsg08

2k rpm = 78-80mph

ttruex

Hmmm, sounds like I may have something not quite sorted, then. I have the 5 spd auto, and at 80 MPH, I see much higher revs.

Possible causes?

I've read a bit about the convertor lock up solenoid going flaky with contaminated/dirty Trans fluid. Could it also possibly be a conductor plate issue?

I was having shift shudder issues, which seemed to have gone away with a fluid/filter change. I'm wondering if I should swap out another 4 qts of fluid and see if things improve?

cmriv

shoulda probably just replaced the conductor plate while the pan was off. those are plug and play and require no programming. My guess is useless though with out the correct diagnosis tree performed...

ttruex

well, pan drop is less expensive than replacing the plate, and since it wasn't exhibiting any other conductor plate symptoms, I thought it would be worth a shot on the fluid/filter swap first. Unless the TC has a dedicated solenoid that is kaput, but I doubt one would fail without the others showing signs of trouble as well.

Ah, well, a bit more research to do. It definitely sounds like something isn't kicking in at speed.

bflaig79

2003 E500 5 Speed

I am a little over 2,000 RPM when I ride about 65 on freeways. Doesn't seem to be a problem and shifting seems normal.