Always use DEXRON®II ATF. The use of ATF Type F or any other fluid will cause severe damage to the transmission.
There are two basic types of automatic transmission fluid. They have radically different viscosities, meaning that they will behave quite differently as to both clutch operation and seal efficiency, which are critical aspects of automatic transmission operation. The Type F fluid is used only in certain transmissions used in Ford Motor Co. products. Using it in a General Motors Corp. automatic transmission will produce disastrous results, including leaks and rough shifting.
The fluid used in G.M. units, as well as many other products, was originally known as Type A. An additive package that met Type A viscosity requirements but also included appropriate resistance to breakdown at high temperatures and leakage was developed and named Dexron®. It incorporated a rare type of whale oil that became unavailable in 1973. A new designation, Dexron®II was developed to replace the original Dexron®, utilizing soybean oil rather than whale oil. Dexron®II meets all the basic standards for what had been Dexron® and Type A.
It is vitally important to understand that, while some older G.M. vehicles might have been able to use one of the earlier designations, all the models covered in this information should use only Dexron®II. In case you should run into remaining supplies of either Dexron® or Type A fluid, it is important to understand that:
- Only Dexron®II should be used in the models covered by this information.
- You must not allow yourself to be sold on the use of the wrong designation, merely because the fluid is of the same basic type. The wrong fluid could work for some time without producing problems, and then create them many miles later.
See Figures 1 and 2
Check the automatic transmission fluid level at least every 7,500 miles. The dipstick can be found in the rear of the engine compartment. The fluid level should be checked only when the transmission is hot (normal operating temperature). The transmission is considered hot after about 20 miles of highway driving.
- Park the vehicle on a level surface with the engine idling. Shift the transmission into NEUTRAL and set the parking brake.
- Remove the dipstick, wipe it clean and then reinsert it firmly. Be sure that it has been pushed all the way in. Remove the dipstick again and check the fluid level while holding it horizontally. With the engine running, the fluid level should be between the second notch and the FULL HOT line. If the fluid must be checked when it is cool, the level should be between the first and second notches.
- If the fluid level is below the second notch (engine hot) or the first notch (engine cold), add DEXRON®II automatic transmission fluid through the dipstick tube. This is easily done with the aid of a funnel. Check the level often as you are filling the transmission. Be extremely careful not to overfill it. Overfilling will cause slippage, seal damage and overheating. Approximately one pint of ATF will raise the fluid level from one notch/line to the other.
The fluid on the dipstick should always be a bright red color. If it is discolored (brown or black), or smells burnt, serious transmission troubles, probably due to overheating, should be suspected. The transmission should be inspected by a qualified technician to locate the cause of the burnt fluid.
DRAIN, REFILL, AND FILTER CHANGE
See Figures 3, 4, 5, 6, 7, 8 and 9
The four types of pan gaskets on the automatic transmissions covered here are pictured for ready identification.
The fluid should be changed with the transmission warm. A 20 minute drive at highway speeds should accomplish this.
- Raise and support the vehicle with jackstands, preferably in a level attitude.
- The support crossmember may have to be removed on some models. Support the transmission with a transmission jack or equivalent before removing the crossmember.
- Place a large pan under the transmission pan. Remove all the front and side pan bolts. Loosen the rear bolts about four turns.
- Pry the pan loose and let it drain.
- Remove the pan and gasket. Clean the pan thoroughly with solvent and air dry it. Be very careful not to get any lint from rags in the pan.
It is normal to find a SMALL amount of metal shavings in the pan. An excessive amount of metal shavings indicates transmission damage which must be handled by a professional automatic transmission mechanic.
- Remove the strainer-to-valve body screws, the strainer, and the gasket. Most 350 transmissions will have a throw-away filter instead of a strainer. On the 400 and 200-4R transmission, remove the filter retaining bolt, filter, and intake pipe O-ring.
- If there is a strainer, clean it in solvent and air dry.
- Install the new filter or cleaned strainer with a new gasket. Tighten the screws to 12 ft. lbs. (16 Nm). On the 400, install a new intake pipe O-ring and a new filter, tightening the retaining bolt to 120 inch lbs. (14 Nm).
While the transmission pan is removed, you may want to install an after market oil pan drain plug kit, available at a local parts distributor or transmission repair shop. This will make future fluid changes easier.
- Install the pan with a new gasket. Tighten the bolts evenly to 97 inch. lbs. (11 Nm). Do NOT overtighten, gasket may break causing a leak.
- Lower the vehicle enough to add the proper amount of DEXRON®II automatic transmission fluid through the dipstick tube.
- Start the engine in Park and let it idle. Do not race the engine. Shift into each shift lever position, shift back into Park, and check the fluid level on the dipstick. The level should be 1 / 4 in. (6.3mm) below ADD. Be very careful not to overfill. Recheck the level after the vehicle has been driven long enough to thoroughly warm up the transmission. Add fluid as necessary. The level should then be at FULL when the transmission is at normal operating temperature.