Wednesday, May 6, 2009

Transmission Fluid Change - Gear Oil Pump

Oil: it is the life blood of your car. Some would even go as far as saying that it is the lifeblood of modern industry. Most are familiar with the idea that the oil in your car's engine needs to be changed every 3000 miles (is not totally true), but many are not aware that there are other critical lubricating oils in your car that need maintenance as well. Though the service interval for these other oils are much longer than the engine, transmission and differentials both contain oils that need to be serviced. And if you have a four wheel drive vehicle there are the tranfer case and the other differential. Manual transmission and differentials use an oil with a much higher viscosity rating. These oils are described as "gear oil". Both synthetic and regular gear oils are available.

Here are some tips on changing out your gear.

-Remove the FILL PLUG FIRST- Most gear boxes have a fill and a drain plug. Before you drain the old oil, remove the fill plug first. This is sooooo important. Often times the fill plug is difficult to remove or is simply stuck or stripped. If you drained the fluid in your transmission and then find out there is no way to remove your fill plug, you have an inoperative vehicle on your hands, and much bigger problem.

-Filling a gear box can be a really pain in the ass. The fill port is usually located somewhere where you can not simply pour the oil in. In the past I have rigged up a funnel with a 4 foot extension. Then fished the contraption through the engine bay to the tranny. They also have hand pumps which you can use. But pumping 5 quarts of 90 weight oil by hand is no easy task.

If you have an air compressor here is a much better way. You need a hose about two feet long, and a spray nozzle. Drill a hole on top of the bottle, either on the cap or somewhere above the fill line. Drill the hole slightly smaller than the outside diameter of the hose. Force the hose in the hole and push it down to the bottom of the bottle. Drill a second hole on the cap, slightly smaller than the air nozzle. Fire up the compressor. Before attaching the air nozzle to the bottle TURN DOWN THE AIR PRESSURE to about 5-10 psi. Finally get under your car and put the other end of the hose into the fill port, and hit the air.

The pressurized air pushes the fluid down and the hose allows it escape. I usually use one modified bottle and just keep filling it. Bottles with a large cap that allow both holes to be drill in it work very good. All you have to do is swap out the bottle.

Here are two write ups on oil change I have referenced before:

1 comment:

  1. 1. Transmission fluid drains better at operating temperature, so let your car idle for a few minutes first. After turning your ignition off, raise and secure the vehicle. Then, lay down a tarp, some cardboard or a newspaper under at least a two-gallon catch pan. Next, remove the bolts from one side of the transmission pan, being cautious of hot exhaust parts and fluid.

    2. Gradually loosen the other bolts, which should allow the pan to tilt and begin to drain. Once all bolts are removed, lower the pan and dump the remaining fluid into the catch pan. Gently break the gasket seal with a screwdriver, if necessary.

    3. Clean the gasket surfaces on both the pan and the transmission housing. Inspect the pan for metal shavings or other signs of internal damage, and then clean it with solvent.

    4. Remove the old transmission filter and O-ring. The filter contains fluid, so keep the drain pan underneath.

    5. Install the new transmission filter, making sure that its O-ring seats in the appropriate orifice.

    6. Attach the new gasket to the pan with oil-soluble grease – not gasket sealer or adhesive.

    7. Refer to the service manual about using thread sealer on any or all of the transmission pan bolts, then screw in all fasteners finger-tight.

    8. Torque the pan bolts to spec in a spiral pattern starting at the center. Maximum torque is often about 12 pounds per foot.

    9. Lower the vehicle and fill the transmission with the recommended amount of fluid.

    10. Start the vehicle, warm it up, then shut it off and check for leaks. If you don’t detect any leaks, run the vehicle up to operating temperature on level ground, move the shifter through all gears, return to park and check the dipstick while the engine idles.

    Source :