Car doesn't like cruising at 60 in fourth.

nextse7en · #1 02-01-2005, 05:26 PM

Whenever am going between 59-70 in drive my tranny is constantly flipping between 3rd and fourth. below that and it stays in 4th - above that it does the same.

It usually has to run for about a half an hour before this will start happening.

I've been dealing with it - but its getting worse - now it only holds forth for about two seconds - then 3rd for two, then back to fourth.

In the last 2 days - forth will let go entirely - the engine will rev freely for about half a second - then snap back into fourth.

WTF?

Any advice is appreciated - this problem is forcing me to speed to keep my tranny for slipping.

Thanks.
Patrick.

lee · #2 02-01-2005, 05:35 PM

I'm not too sure this is it, but do you by any chance have the dropping resistor unplugged (or defective). There is some threads that talk to gear-searching by some who have unplugged the resistor.

n00b on demand · #3 02-01-2005, 08:46 PM

I think i remember reading a thread where he said he had his resistor unplugged. Not too sure though.

nextse7en · #4 02-02-2005, 02:21 AM

resistor is definatly working and plugged in - I had it unplugged - and it only hunted on the downshift from 3 to 2.

svxistentialist · #5 02-02-2005, 04:46 AM

Quote:

Originally posted by nextse7en
Whenever am going between 59-70 in drive my tranny is constantly flipping between 3rd and fourth. below that and it stays in 4th - above that it does the same.

It usually has to run for about a half an hour before this will start happening.

I've been dealing with it - but its getting worse - now it only holds forth for about two seconds - then 3rd for two, then back to fourth.

In the last 2 days - forth will let go entirely - the engine will rev freely for about half a second - then snap back into fourth.

WTF?

Any advice is appreciated - this problem is forcing me to speed to keep my tranny for slipping.

Thanks.
Patrick.

You don't actually have to speed to avoid this problem temporarily Patrick. The car will drive perfectly well in 3 up to very illegal speeds, and will only be 1 or 2 mpg worse off for the higher revs.

The troubleshooter does not describe this problem or diagnose it.

As your auto is shifting between 3 and D erratically, the first place I would look is a bad or intermittent electrical signal. The obvious one to look for is the ATF oil temp sender. If it is showing too low, the programme tells the box not to shift to D.

Another suspect would be the TCU itself could be faulty, the loom to the TCU could be damaged, or, the signal wire into the loom from the ATF temp sender could be damaged. This wire is part of the loom, and connects to pin 12 in the TCU.

Best of luck sorting it. The temp sensor would be my first place to look.

And drive legally in 3, OK?

Joe

Earthworm · #6 02-02-2005, 12:05 PM

Are you sure it's shifting to 3rd or just unlocking the TC?

Test - when it does this immediately pull the shifter into 3rd and see if the RPM's rise again.

It's possibly the TPS giving a false reading (dirty)

svxistentialist · #7 02-02-2005, 12:55 PM

Agreed David

The TPS would be another electrical area to look closely at.

Joe

oab_au · #8 02-02-2005, 03:39 PM

Quote:

Originally posted by nextse7en
Whenever am going between 59-70 in drive my tranny is constantly flipping between 3rd and fourth. below that and it stays in 4th - above that it does the same.

It usually has to run for about a half an hour before this will start happening.

I've been dealing with it - but its getting worse - now it only holds forth for about two seconds - then 3rd for two, then back to fourth.

In the last 2 days - forth will let go entirely - the engine will rev freely for about half a second - then snap back into fourth.

WTF?

Any advice is appreciated - this problem is forcing me to speed to keep my tranny for slipping.

Thanks.
Patrick.

This sounds a bit like the trouble that Lee had.

The changing back and forward between 3rd and 4th could be the band letting go in 4th. This will change the box back to 3rd till it grips again to hold 4th.

But the fact that as you say, that 4th will let go entirely - and the engine will rev. This can only be the high clutch slipping to allow the reving. It could be low line pressure, but as in the past, I would say the box is on the way out.

Harvey.