Automatic Transmission Service and Repair - Frequently Asked Questions

30- Which type of transmission gets better gas mileage, a standard or automatic?

A standard transmission is generally more fuel efficient that an automatic because the automatic needs a pump to produce pressure for the unit to work. The pump takes some of the power from the engine to run. Also, the automatic uses a torque converter to transmit power from the engine into the transmission, and is a fluid coupling and therefore does not transfer 100% of the power mechanically as a clutch in a standard will. Later model automatics have a lock up torque converter that will provide a mechanical connection with the engine, but not in reverse and only in the gears above 1st.

In a word, no. When water gets inside of an automatic transmission, the friction lining of the clutches absorbs it and dissolves the glue that attaches the material to the clutch plates. Usually, some amount of water will come out of suspension and form white gummy masses in various areas of the unit.

Simply put, this is why the unit cannot be flushed to remove all of the water.

In addition, the presence of water will start rust forming on the ferrous metal parts throughout the unit. The amount of water and the length of time that it is inside of the unit will determine the extent of the damage, but the resolve to the problem will be to overhaul the transmission.

There is no shortcut that will "repair" the situation! It's only a matter of time before the unit will exhibit abnormal operating characteristics and fail completely.

FYI, water usually gets into the transmission in one of two ways. First, all transmissions have a vent to maintain equal barometric pressure inside of the transmission. If the vehicle is driven through water (as in a flood) and the water level is at or above the vent, the water will cool the unit lowering the internal temperature and water is drawn inside of the transmission.

Also, virtually all modern transmissions (some were air cooler in the old days) have two cooler lines that route from the transmission to a special tank the radiator to cool the transmission fluid. If this special tank ruptures, transmission fluid can enter the radiator and water can enter the transmission. In this case, the cooler tank in the radiator will have to be replaced as well as rebuilding the transmission. One of the common indications of transmission fluid in the radiator coolant is the "strawberry milkshake" appearance of the coolant.

Click here for an Automotive Service Association article on water in the transmission.

A transmission service consists of a test drive, removing the transmission pan, draining the fluid (about half of the total), changing the filter and pan gasket, test driving again, and adjusting the linkage and bands if necessary.

The advantages: The filter is changed along with the fluid similar to an engine oil change and the vehicle is test driven and linkage and bands (if applicable) are adjusted. Usually, this service is done at a facility that has more knowledge about transmissions.

A transmission flush consists of attaching a machine to the transmission and removing virtually all of the fluid and replacing it with new fluid. Unless the pan is removed, the filter cannot be changed. At some facilities, the vehicle is not test driven or the linkage and bands adjusted.

The disadvantages: Most of the time this service is done at a facility that has less knowledge about transmissions and none of the additional services are performed.

Occasionally, abnormal operating symptoms arise because the valve body and/or other control items are contaminated by residual wear material that is disturbed and circulated during the flushing process.

33- I found this piece in the transmission pan of my Ford. What is it, and where does it go?

The plug is used to fill the filler tube hole in the transmission case before the unit is installed in the vehicle on the assembly line. When the filler tube is inserted, the plug falls into the pan where it remains until the pan is removed. It served its purpose and serves no useful function any more.

Many people have tried to find a place to install it or though it might be the cause of some abnormality, but alas, it's has no current function. You can toss it.

That's the age-old question when confronted with a major repair on an older vehicle. Many people buy or lease a new vehicle to escape the higher cost of a repair.

Cars are built better today than ever. A properly maintained Honda can last 500,000 miles as an example. The key word is "properly." Some owners just change the engine oil and keep it clean. That attitude will not provide longevity! Regular, periodic maintenance, as outlined in the owner's manual is the key.

The table below shows an example of whether to keep a 1992 Honda Accord you already own, put a ton of money into fixing it up and keeping it verses what it costs to replace it. The chart is based on a 7.9% interest rate and the lease is based on what Honda has advertised in recent years.

It's over $3,000 less to keep your present car than to buy a new one, and $9,000 less than leasing. Check with your accountant, but this example can be very enlightening.

Total Expenses over 3 years	Keep 1992 Honda Accord	Purchase 2000 Honda Accord	Lease 2000 Honda Accord
Down Payment	0	$1,000	$1,000
Sales Tax	0	$1,205	$561
License Plates	$350	$1,040	$1,040
Insurance	$1,776	$2,714	$2,714
Maintenance/Repairs	$6,000	$1,000	$1,000
Interest Expense	0	$3,095	0
Lease Payments	0	0	$9,000
Depreciation	$1,700	$4,245	0
Total Cash Outlay	$9,826	$14,299	$15,315
Less Equity at end	$4,000	$5,120	0
Net 3 Year Expense	$5,826	$9,179	$15,315

Frequently Asked Questions Quality Transmission Service, Tempe, Ariz