Before the automatic transmission is removed for repair of a suspected malfunction, it is imperative that the cause be traced and confirmed. To do this requires specialist experience and various gauges not normally found in the DIY mechanic's workshop.

If any fault arises that cannot be cured by attention to the oil level or the adjustment of the control cables, take the car to a BL main agent or an automatic transmission specialist for diagnosis and repair.

An a guide to determining if a fault exists, consult the change speed chart below. The tests should be made with the gear selector in D.

Throttle position Gear change          mph              kph
Light      	1-2               	10-14                 16-22
		2-3		15-19		24-30
		3-4		20-24		32-39
Kickdown	1-2		25-33		40-53
		2-3		37-45		60-72
		3-4		49-57		78-91
Kickdown	4-3		43-39		70-64
		3-2		35-31		56-50
		2-1		22-18		35-29
Closed (roll-out)	4-3		20-16		32-36
		3-2		14-10		22-16
		2-1		8-4		12-6