Could it need transmission fluid and how much does it need? The dipstick does not seem very accurate. It only rattles when idling, not driving. Any ideas?
The knocking sound could be a cracked flywheel, or loose bolts at
the torque converter or the torque converter itself. Below is the
procedure for checking your transmission fluid.
Drive the vehicle for 15-20 minutes to allow the transmission to reach operating temperature.
Park the truck on a level surface, apply the parking brake and leave
the engine idling. Shift the transmission and engage each gear, then
place the gear selector in
Wipe away any dirt on the transmission dipstick to
prevent it from falling into the filler tube. Withdraw the dipstick,
wipe it with a clean, lint-free rag and reinsert it until it seats.
Withdraw the dipstick and note the fluid level. It should be between the upper (FULL) mark and the lower (ADD) mark.
If the level is below the lower mark, use a funnel and add fluid in
small quantities through the dipstick filler neck. Keep the engine
running while adding fluid and check the level after each small amount.
Do not overfill.