How To: Junkyard Transmission Shopping 101

Shopping for a junkyard transmission can be a dicey prospect, but it can also pay big dividends. Sometimes the salvage yard is the only place to find rare transmissions and vintage parts. You have to be very careful in selecting a junker transmission, but it can be done. Here is a general guideline of what to do and look for. As always, this is just a guide, and does not guarantee a working transmission. Get to know your salvage yard or parts provider. Ask about guarantees, refunds for broken equipment, etc. Caveat Emptor.

1.) Do your homework: The first thing to do is determine what type and make of transmission you want (e.g. Automatic, Manual, Ford, Powerglide, etc.). Once you know what transmission you want, be sure to know all the variations (if any) there are of that transmission. Differences in the same model transmission can include, but is not limited to, different drive ratios, bolt patterns, input/ouput spline count and length, etc. Read up on casting numbers, and years of production, which donor vehicles you can expect to find a specific transmission in, as well as specs and dimensions.

2.) Be sure it will fit: Sounds like simple common sense, but be sure the transmission you want will fit your application. This is especially important if you are swapping a manual transmission for an automatic (or vice versa), or if you are planning to use a different make of engine and transmission (e.g. Chevy Engine to Ford Transmission). Measure to make sure that the dimensions of the transmission you want will work. If modifications to stock components like crossmembers, sheet metal tunnels, driveshafts, etc., are required, be prepared for fabrication work, or to pay for it.

3.) Have a line on parts: If you know your transmission will require an adapter, new bellhousing, specific torque converter, or pressure plate and clutch to work in your application, be sure you know exactly where to obtain the necessary parts, and that the parts are available. For automatics, know where to get a new torque converter. For manuals, know where to get a new clutch and pressure plate. Junkyard torque converters and clutch/pressure plates should be avoided at all costs. It is a well spent $200-$500+ for a new torque converter or clutch/pressure plate.

4.) Be an observant shopper: Take a flashlight. Once you have located the transmission you want, if it is still in a vehicle, have the salvage yard pull it for inspection. Here is what to look for in an automatic and manual:

Automatics: Remove the transmission drain pan plug and drain the transmission. Look for debris in the ATF fluid and make note of how clean/dirty the fluid is. If the drain plug is magnetic, inspect it for metal shavings or debris. Next, turn the transmission upside down and remove the transmission drain pan. Grab the input shaft and pull/push it to check for excessive play. Rotate the input shaft while inspecting the internal rotating gear assembly. Cycle the transmission through all the forward and reverse gears while rotating the input shaft. The transmission should go into all the gears with minimal effort. Use your flashlight to look at the rotating gear assembly for cracks and abnormal heat scorching. Inspect the gear teeth for damage. Be sure the output shaft rotates when the transmission is in gear and you rotate the input shaft. Listen carefully to the sounds the transmission makes are you rotate the input shaft. Excessive grinding, noisy bearings, or overly loud gear meshing are red flags. Finally, grab the output shaft and pull/push it to check for excessive play. If no obvious problems are noted, then you likely have a good junkyard transmission.

Manuals: Remove the drain plug and drain the transmission. Look for debris in the gear oil, and make note of how clean/dirty the oil if. Gear oil that appears very cloudy or milky can indicate the presence of water, and are red flags. Inspect the tip of the input shaft for signs of pilot bearing failure and wallowing. Grab the input shaft and pull/push it to check for excessive play. Rotate the input shaft and cycle the transmission through all the forward and reverse gears. The transmission should go into all the gears with minimal effort (some older manual transmissions do not have synchro gears, and cycling the gears may require a bit more effort, but should not be difficult).Listen carefully to the sounds the transmission makes are you rotate the input shaft. Excessive grinding, noisy bearings, or overly loud gear meshing are red flags. The output shaft should spin when the transmission is in a forward/revers gear, and the input shaft is rotated. Finally, grab the output shaft and pull/push it to check for excessive play. If no obvious problems are noted, then you likely have a good junkyard transmission.

5.) Re-sealing and checking you transmission: Now that you have your new used transmission home, it's time to re-seal potentially problem areas. Automatics should get a new pan gasket. Manuals should get a new gasket or sealer on the shift tower. Other seals may need to be replaced depending on the transmission make and type. Refill you transmission with the appropriate gear oil or ATF fluid, and let it sit for 48 hours. Check for seepage around all the seals, the input/output shaft bearings, and drain plug. If all looks good, then you are ready to install the transmission at your convenience.

There you have it! Hope this proves to be useful. One last disclaimer: this is just a guide, so don't come crying if you follow these steps and end up with a bum junker transmission. On that note- good luck. Cheers.

 

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Anouther thing to add, i always look for a car that has been wrecked, cuz you know it was driving before it was junked