Removing a Drive Shaft When Being Towed
By Norman Nock
Originally published in the Austin-Healey Magazine, February 1982
Editor's Note: This article by Norman Nock from Stockton, CA is tied to the November issue in which Ken Rocke from So. Cal submitted a diagram and article for building a Healey tow bar. To disconnect the drive shaft or not to disconnect, that is the question. Read on and get the answer...
QUESTION: Do I need to remove my drive shift on my Austin Healey when being towed?
ANSWER: If in doubt remove the four nuts & bolts that hold the rear universal yoke to the flange on the pinion of the differential, push the drive shaft forward into the tunnel and secure the driveshaft (strong wire will do). The pinion flange will spin with the rotation of the rear wheels, it is imperative that the driveshaft is secured in such a way as it can not
come in contact with the spinning flange of the differential.
When towing your Austin Healey without removing the driveshaft, there are certain problems that can develop.
The oil level in the transmission, if at its correct level on the dip stick will be just covering the lower balls of the rear transmission main bearing, raising the level of the oil in the transmission by about 3/8" will help lubricate this ball beating. If the car is towed with a low oil level, there is a strong possibility of damaging the rear ball bearing due to lack of oil. Remember that some of the extra oil will have to be removed from the transmission to return the oil to its correct level, if this is not done the front transmission seal could start to leak.
Standard transmission without overdrive. There is no powered movement of the gears within the gear box (except 1st) to cause the oil to be picked up by the cluster gear, this in turn would not lubricate the bushes or rollers between gears and spinning main shaft. Some transmissions have a system that lubricates the bearing from the spinning main shaft but not the non-overdrive Healey.
Standard transmission with overdrive with the overdrive oil pressure system working correctly, the main shaft is supplied with oil via holes within the main shaft from the uncovered relief holes inside the accumulator cylinder housing. (Roller bearings on the main shaft are lubricated). There is a possibility if your overdrive does not work under normal driving conditions, you are not lubricating the main shaft rollers to gears. If your overdrive works but is slow and sluggish when changed, you could still be experiencing the same problem, no lubrication through the main shaft. Follow your factory service manual and change transmission oil and clean the filter every 6,000 miles. It is essential that an approved lubricant be used when refilling. Trouble may be experienced if some types of extreme pressure lubricants are used because the planet gears act as a centrifuge to separate the additives from the oil. Use S-A-E 30 non-detergent.
Be safe and disconnect drive shaft.
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