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Transmission Swap: Remanufactured Transmission A 1985 Chevy El Camino gets cured of the hesitation blues with a remanufactured transmission. From "Weekend Mechanic" episode WKM-406

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	Disconnecting the vacuum modulator hose
	Checking the throttle cable

Transmission Fluid and Preliminary Checks

The first thing to check is the transmission fluid. Refer to your owner's manual to locate your transmission dipstick, and also whether or not the engine needs to be running and whether the fluid needs to be hot or cold. In our case, the dipstick is located at the firewall. For our vehicle the engine should be running at idle, and the fluid should be around 200 degrees.

Check fluid level as well as the color and condition of the fluid.

Weekend Mechanic DIY FYI: If it's in good condition, the transmission fluid should have a clear reddish tint and no burnt odor.

Next, remove the air cleaner to access and disconnect the vacuum modulator hose. Inspect the vacuum modulator hose for signs of transmission fluid. Fluid in the hose means that transmission fluid is leaking into the engine. In our case, the hose looks clean.

Note: Many older vehicles have a vacuum modulator hose which can go bad and may cause the car to stay in low gear.

Next check the throttle-valve cable (TV cable) to make sure it's connected and that the valve's not stuck. The throttle valve cable controls the transmission line pressure and adjusts shift points. Ours appears working well.

The next thing we'll need to do is raise the car up and take a close look at the transmission. Further inspection reveals leaking transmission fluid around the transmission pan.

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Figure A

Removing the Transmission Pan

Safety Alert: As a standard safety precaution, never rely solely on a jack to support the weight of a vehicle. When using a jack to access or work beneath a vehicle, always use jack stands for support. Make sure that the jack and stands that you use are rated for the weight and type of your vehicle.

• With the vehicle securely on a lift (or jacked up and supported by jack stands), loosen the transmission pan bolts slowly and evenly to allow the transmission fluid to drain.

• After letting the fluid drain for a while, remove the bolts (figure A) and carefully lower the transmission pan.

• Inspect the transmission fluid closely. Evidence of metal flakes or pieces of material are signs of big problems. In our case, metal flakes and debris were visible in the fluid, confirming mechanical failure in the transmission and indicating that this one is in need of replacement

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