efxr6wagon

My alternator died last week, so I had it replaced. Now I have three brand new problems:
1) The transmission is shifting at high revs - like it's in "power" mode. Under minimal load (light throttle) in Drive, the 1-2 upshift comes at 2900RPM, and 2-3 at 2600RPM. Previously, this would have been at 2000RPM or less.
2) Idle is all over the place, even at full operating temperature: sometimes a normal 650-700RPM in Drive, sometimes 1100-1200RPM or even higher. After idling for a while, it tends to "hunt" up and down, and there is a noticeable surge while driving normally, especially when cold.
3) Sometimes when starting the engine warm, I get a loud clattering sound from the "belt" end of the engine - something like a loose chain. It goes away after a minute or two of driving.

Any idea what could cause these oddities, and how to fix them? Could they be caused by or related to a failed alternator? Thanks.

efxr6wagon

The problem has gotten worse - now it 'bangs' when going into gear (forward or reverse). So I checked the trans fluid level, following the prescribed procedure (level car, light warm up, 3 seconds in each gear, leave in Park with engine running). When I unscrewed the check plug, 2.5 quarts/litres of trans fluid came out. That sounds seriously over-filled to me. Would that cause the problems I have been experiencing? And could it have caused some permanent damage? If so, what damage should I be checking for?

The weird thing is that we have not added trans fluid since we bought the car three years ago, so it has been overfilled the whole time. My parents took it for an extended trip (2500 miles/4000 kms), including major mountain passes, with no problems.

I am going to let the car cool down and try the exercise again to make sure I haven't screwed it up. Any advice? Thanks.

efxr6wagon

I checked the level again, and no change. I measured the ATF in the drainpan, and it was 4 quarts/litres overfilled! I took it for a drive, and it is much better - seems to have stopped 'banging' going into gear.

In the ATF I drained was a significant quantity of what looks like fine sand. That can't be good. There was no burnt smell and the ATF colour is dark red, with maybe a slightly brownish tinge. Should I be worried?

It is still shifting at high RPM, so maybe that is something else.

The weird rattling sound is coming from the air conditioner compressor, and goes away when I release the belt tension.

nauticstar87

might possibly be time for a rebuild, but it'd be worth it to get the tranny flushed and change the fluid, how many miles you got.

efxr6wagon

It has 135,000kms/ 84,000 miles. I wouldn't be surprised if it's the original trans fluid. A transmission rebuild would cost almost as much as the car is worth, so if it needs a rebuild it's a write-off. Buying a used transmission may be a cheaper option (about US$500). A flush will cost me about US$160, but may not help. Has anyone had experience with Lucas Transmission Fix? Is that worth a try?

Thanks for your help.

efxr6wagon

Well, I put some Lucas Transmission Fix in it, and it seems to have stopped the banging when going into gear. It is still shifting at very high revs (3500-4500 RPM at normal throttle, 2800-3000 RPM at lightest possible throttle). Also it doesn't want to lock up the torque converter. And the idle is still all over the place - sometimes as high as 1500 RPM. Could the throttle position sensor being causing any of this?

My TPS has a voltage range of 1.4-4.6 volts. Could 1.4 volts be too high for the engine and trans control computers to recognise it as idle? My Haines manual doesn't give a specific range for the TPS, but says potentiometer-type sensors "typically" go from 0.2-5.0v.

Any help would be appreciated. Thanks.