Mileage dropping - Is it transmission ? - Toyota Nation Forum : Toyota Car and Truck Forums

RayNManchester · 02-01-2011, 07:34 PM

My 2001 Toyota Camry has 166,000 miles and recently the mileage dropped from average 27 mpg to 20 mpg. The Automatic Transmission Fluid appears to be topped up. On steep hills, the transmission will slip (based on the RPMs).
Is this a transmission problem? Anything simple?
If it is a transmission problem, can I live with it for awhile ?

Stillrunning · 02-01-2011, 07:41 PM

When was the trans fluid last flushed with new?

***JohnGD*** · 02-01-2011, 08:37 PM

What's the condition of the ATF? When was it last replaced/flushed?

It's hard to telling going uphill, because we normally step on the gas and the transmission can downshift (higher rpms). I'd check on level ground and see when you step on the gas if the rpm flares up before going anywhere.

In what gear(s) do you notice the slips?

RayNManchester · 02-02-2011, 01:04 PM

I know that the transmission fluid was exchanged at 116,000 miles.
In addition, Toyota has performed every major maintenance every 15,000 miles.
They have also done almost all the oil and filter changes at 5,000 miles increments.
I would have to review their records to see if the ATF was exchanged since 116,000 miles.
I know they inspect the ATF every 30,000 miles.

My wife and I drive the car in the standard drive position (overdrive button engaged) at all times.

carsrus · 02-02-2011, 02:01 PM

Its probably not a transmission problem. Drive towards a hill with a consistent gas pedal. When your going up do not move your foot at all. If the rpm don't change your fine.

Also, do you have to rev up a bit to get it to move from a stop? That would be the biggest sign of a slipping trans.

Its the winter so MPG numbers are also gonna be whack. If it runs good I wouldn't freak out.

***zythr*** · 02-02-2011, 06:45 PM

Quote:

Originally Posted by carsrus

Its probably not a transmission problem. Drive towards a hill with a consistent gas pedal. When your going up do not move your foot at all. If the rpm don't change your fine.

Also, do you have to rev up a bit to get it to move from a stop? That would be the biggest sign of a slipping trans.

Its the winter so MPG numbers are also gonna be whack. If it runs good I wouldn't freak out.

That's right. Winter blended gasoline, also called oxygenated gas, does lead to lower mileage in winter months.

RayNManchester · 02-02-2011, 10:37 PM

Thank you.
I plan to monitor the situation until it warms up (probably in the next 30 days or so).

Driving on the flat today at 60, if I stepped on the gas, the RPM would jump, then slide back and the car would accelerate.

The car does not appear to have a problem moving from a stop position, even if on a hill.

***JohnGD*** · 02-03-2011, 08:18 PM

Was this done with steady gas pedal. With a little more gas the RPM should hold steady for a very brief while and then jump slightly? Maybe 200-300 rpms? That would be the torque converter clutch disengaging.

You can also drive slower (50 mph) and with OD off try the same. See if you see similar behavoir.

Your 1st gear should be ok.

If you let go the gas the rpm may go lower because of one-way-clutches free wheeling, giving you a false impression of high rpm increases.

Quote:

Originally Posted by RayNManchester

Driving on the flat today at 60, if I stepped on the gas, the RPM would jump, then slide back and the car would accelerate.

The car does not appear to have a problem moving from a stop position, even if on a hill.

Albetime · 02-04-2011, 11:50 AM

I have noticed on my 97 camry that my mileage lost about 50 miles per tank and found that the converter was not locking up properly. Check the RPM and speed to see if that is a factor. If I remember correctly, at 55 mph the RPM is about 2200. You stated that the trans is slipping but also a suttle slippage like the converter may not be noticed as in my case. Try to add some TransX or Seafoam trans additive. This is not a fix but my help to prevent some of the slippage. If your trans is slipping from loss of internal fluid pressure that can affect the pressure required to lock up the convert. Also I have noticed on my car that my problem is worst when the trans fluid is cold.

RayNManchester · 02-04-2011, 03:04 PM

Thank you all for your suggestions on what to monitor and what to try.

I don't plan to make any drastic decisions for a couple of months, unless this behavior changes drastically.

Right now, it might cost me $10.00 a refill for the loss in mileage.

I will report back in a month.