accelerate to 90MPH. Is there a sensor of some sort that tells the EGS when to lock-up the torque converter clutch? Also - as long as I keep the car at 90MPH (which is probably more like 85MPH because of the speedometer error), RPMS stay steady at just over 3,100, they don't ever drop down unless I take the foot off the accelerator and slow down to 85MPH or so - then they go down to 2,800 or so. Basically, it feels like the car is 'stuck' in accelerating mode - this is in 'D' mode. Steptronic '5' has the same behavior, and so does the cruise control.

The car is an I-6 530i with 135K miles on the speedometer. I am hesitating doing something to my auto transmission as noone can tell me exactly what the problem is (several indies looked at it) as it could be some sensor feeding messed up data to the EGS computer and not a mechanical failure of any kind...Transmission shifts perfectly otherwise. Any suggestion would be appreciated. I don't think there is a reputable indie specializing in auto transmissions in my (Philadelphia) area. Thanks:help

This just started or has it always been this way? Sounds like thats just the gearing of your car to me, but that's just a shot in the dark lol.

No CEL light?

I had sam problem. I put that TC sensor (solenoid) and problem is gone.

this doesnt happen with my manual... jk!

No CEL light?

I had sam problem. I put that TC sensor (solenoid) and problem is gone.

I have a CEL light along with gearbox light.

When I drive 75-80 mph on the highway the car shifts down to 3 or 4th gear and I'm at 3000 rpms. Also the gearbox and CEL light come on simultaneously. I then usually get home, turn off the car, and when I turn it back on the lights reset except for the CEL.

When I drive below 70 mph I have no problems.
Any ideas?

I have a CEL light along with gearbox light.

When I drive 75-80 mph on the highway the car shifts down to 3 or 4th gear and I'm at 3000 rpms. Also the gearbox and CEL light come on simultaneously. I then usually get home, turn off the car, and when I turn it back on the lights reset except for the CEL.

When I drive below 70 mph I have no problems.
Any ideas?


Did you ever find out what codes you are getting? That would help.

I just ran to autozone and its a p0735 any ideas?

It says "incorrect gear ratio condition in 5th gear".

I really don't want to spend 3-4k on a new trans, bump.

(Is the OEM trans ford?)

to the OP that really sounds kind of normal to me, the TCC will take cues based on the amount of throttle application, once you are getting up to 90mph It may just stay unlocked. The RPMs sound about right for 90mph.

I just ran to autozone and its a p0735 any ideas?

It says "incorrect gear ratio condition in 5th gear".

I really don't want to spend 3-4k on a new trans, bump.

(Is the OEM trans ford?)

If it's domestic, it'd be GM. Not sure if you have that one though. I don't know the automatics.

to the OP that really sounds kind of normal to me, the TCC will take cues based on the amount of throttle application, once you are getting up to 90mph It may just stay unlocked. The RPMs sound about right for 90mph.

I agree...or maybe I'm not understanding your problem fully. You said when you decrease your speed from 90 to 85 or whatever your rpms drop. When you stay in any given gear and you decrease your speed your engine speed also decreases...

I agree...or maybe I'm not understanding your problem fully. You said when you decrease your speed from 90 to 85 or whatever your rpms drop. When you stay in any given gear and you decrease your speed your engine speed also decreases...

In a gear as tall as 5th, I don't think it would drop that fast only over 5 mph.

It's either dropping a gear or locking up the TCC.

In a gear as tall as 5th, I don't think it would drop that fast only over 5 mph.

It's either dropping a gear or locking up the TCC.


I don't know those rpms sound about right for those speeds...and he didnt say specifically how much he decreased his speed...he said from 85 mph to 85 mph...i think the OP made a typing error.

I have the 4 speed auto trans and I'm at around 3000 rpm at 80 mph in 4th gear...i would imagine the 5th gear ratio on the 530 is similar.

Change that TCC solnoid, oil, filter and gasket, reset the codes and start from there.

my old 530i 5 speed would be at exactly 3K RPMs at 80.... your 3,100 at 90 doesnt seem right...

2003 530i/5

I have watched my RPMs with a 4 speed and I see about the same thing. There is about a 200 RPM swing between cruising and accelerating while maintaining the same speed that has nothing to do with TCC lockup. This is just the normal behavior of the Torque converter(ie there has to be a difference in speed between the input housing and the stator for it to work which is what a TCC is there for) I think from what i have seen you have no problem it just looks a little odd.

As to RPMS at 90 mph being in the 3100 range, again this seems to be about normal. In your top gear the RPMS build pretty slowly due to the very tall gearing.