How to Check the Transmission Fluid in a 1991 S-10 With a 4.3L
- 1). Park the truck on a level surface. Place the jack under the right-side frame rail, and raise it until you have enough clearance to slide under the truck. Secure the truck with two jack stands under the frame rails. Repeat for the left side to level the truck.
- 2). Slide under the right side of the truck. Place the drain pan under the transmission. Look at the right side of the transmission to locate two threaded plugs, one above the other.
- 3). Loosen and remove the upper plug. Fluid should run out of the hole. If it does, replace the transmission fluid and tighten the plug. If no fluid runs out, pump fluid into the hole until it begins running out. Then replace the transmission fluid, and tighten the plug.
- 4). Raise the truck and remove the jack stands.
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