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Driveshaft FAQ Index

Driveshaft related questions pertaining to Five/Six speed conversions. Be sure to contact us if you do not see an answer to your question.

  • I have a rear axle that has a large U-joint size, is there a U-joint that crosses over to a smaller size driveshaft tube?

    Yes, Most of the later Mustang and truck with 9" axle come with larger size U-joints yokes. We offer a U-joint that can be installed on a stock drive shaft to couple the two together.


  • How do I measure a drive shaft I have now?

    Most driveshaft lengths are referanced by the center to center position of the U-joints. The slip yoke is a fixed length. After the yoke has been positioned, a tape measure can be used to measure the U-joint center to the rear yoke face of the rear axle.


  • How much slip yoke should be engaged into the transmission?

    There should be at least 3/4" of slip yoke showing for most cars. Trucks or off road vehicles will require more if they are lifted and the axle travels a lot up and down.


  • Does an aluminum driveshaft require special U-joints?

    Yes, it requires U-joints that are coated to prevent the steel cup from eroding the aluminum drive shaft yoke causing the drive shaft to wear out and vibrate over time. All of our aluminum driveshafts are equipped with these cups.


  • How much weight saveings can I except from an aluminum drive shaft?

    About 8 pounds over a 50" long steel drive shaft.


  • Is it better to purchase a ready made driveshaft instead of modifying the old one?

    In most cases it is better to replace the drive shaft when installing a conversion. The cost of replacing the yoke, two U-joints, shortening the tube and rebalance is nearly the same cost of a new one. Besides, it is ready to bolt and ready to use, saving you time.


  • How do I know when I have too much drive angle?

    More than 5-6 degrees is too much. For help with measuring angles check out the Driveline Angle Finder app for your smart phone.


  • Will I have to rebalance the drive shaft after installing the new slip yoke or shortening of the driveshaft.

    It is highly recommended, as the parts are not always balanced. It is best to shorten the driveshaft from the back half rather then from the front. Any good driveshaft shop will be able to make these changes.


  • Do I need to replace my drive shaft slip yoke when installing a T-5, Tremec 3550/TKO/TKO500/600?

    Both T-5 and Tremec 3550 use a 28 spline yoke which is the same as a C4, toploader or AOD. 3 speeds and T-10 4 speeds transmissions used 25 spline slip yoke so a replacement is needed. Tremec TKOs require a 31 spline outshaft, so a 31 slip yoke is required. C6 also have 31 spline output shafts. Call us if you need a replacement yoke.