ROVER P6 AUTO GEARBOX CHANGE
QI have a 1970 Rover three thousand five hundred (P6) automatic. The gear changes appear to be inconsistent, and whilst sometimes the box will change into top gear at 15mph, at other times it will not change until I am travelling at about 45mph. I would ideally like it to change at a more consistent 25-30mph. Does this sound like something that can be adjusted easily? Graham Chard
A
The Borg Warner model 35 gearbox fitted to your P6 will take a few different factors into account when deciding at what speed to change gear, and when under load the gear change will occur later than when coasting downhill.
The first important check is to ensure that the gearbox oil level is correct. This should be done by the book as it is easy to get a false reading, and any error with the level of the oil can cause the gear change to become harsh. It can also cause early or late changes. The correct procedure is to drive the car for at least 15 minutes to ensure that the gearbox oil is suitably warm and circulated. Then park the car on a level surface and with the engine still running and your foot firmly on the brake pedal, select each gear in turn and leave it engaged for around five seconds before
moving on to the next one. Once the full travel has been achieved, place the gear lever in park.
Immediately after placing the gear lever in park and with the engine still running, the gearbox oil should be dipped. The oil should be at the HOT mark on the dipstick. It should also be a nice bright red colour – any tinge of brown accompanied by a slight burning smell may indicate internal problems with the gearbox. ATF-G or Ford spec M2C-33G oil is recommended, and Dextron fluid should not be used as this will damage the clutch plates. You should also check that the kickdown cable from the throttle appears to be operating correctly, and that the cable runs smoothly when the accelerator is pressed. As the gear change does vary, it may be a faulty cable but I would not expect it to be due to an adjustment issue.