Haynes glitch on auto box information?

[StevenWilliams]

Originally Posted by James.uk

You may notice lockup on a gentle downhill if you keep your feet off the pedals.
.

It does indeed.

Perhaps this accounts for the great MPG you get on a motorway run when not overtaking a lot. It's much higher than I would have expected and when really making the effort to keep a constant speed I can get near 40 mpg on a motorway run. I've now managed to get 450 miles out of a tank of fuel. Perhaps this is a record Bored as heck however.

[jim_mcglynn]

hmmm. I have noticed an audible & revs change around 2100rpm to 2000rpm, but assumed it was VIS motors doing their stuff. So, is this the lock then, do you reckon?

[robwijnstok]

Originally Posted by James.uk

Most auto boxes lock up in top gear, but as the lower speeds are rarely held constant for long, the lockups dont get chance to operate.

You may notice lockup on a gentle downhill if you keep your feet off the pedals.
.

That is exactly my point. Why should Rover/Jatco develop a gearbox with a feature of locking on 2, 3, and 4th gear also, when it will never have a chance to work in normal use?
Like I have said, I have a daily drive to work 15km long at 80km/h (50Mmls/h) maximum speed. During this speed I have the cruise control ON, always! This is because of extensive speed control of our regional Police on that road. On this road there are a couple of spots where there is little, very little climbing say in 100 meters, you climb 1 meter. When I come on the starting point of the “climbing” part, immediate response of the cruise control is there, and the engine revs are 200-300rpm higher there, speed stay’s the same like is should. When the climbing is over, the revs drops again and again not a noticeable sign of locking. When I have this on the motorway on cruise control, and the climbing is not very steep, I can hear that the engine has to work harder, but the revs stay the same, and so is my speed at that time.
This makes me think that the locking of the torque converter is working OK in fifth gear, but not in the other three gears.

Originally Posted by StevenWilliams

It does indeed.

Perhaps this accounts for the great MPG you get on a motorway run when not overtaking a lot. It's much higher than I would have expected and when really making the effort to keep a constant speed I can get near 40 mpg on a motorway run. I've now managed to get 450 miles out of a tank of fuel. Perhaps this is a record Bored as heck however.

How do you do that, 40mpg? You must use a very, very good quality wax or so, what makes the air resistance index of your car so low that you can do 40mpg. I see other members claim also very high mpg’s. How is that done by you guy’s…?
Normally I would think you drive NOT an auto gearbox, but in an earlier post on this threat I saw that you do.
Driving down hill all the time?
Driving at very low speeds?
Brim to brim or measured by the OBC? Tip, if you have got it from your OBC, don’t use the brim to brim method, or disillusion will become part of you…
When I am driving on the motorway I can do 30 to 33 mpg at the most! That is brim to brim and aircon off. Full service and cam belts were done a couple of weeks ago, and no engine fault codes seen by T4 at that time so engine must be healthy.
I saw that Phil a while ago in another threat, noticed mpg improvement after using Shell V-Power, on my car V-Power or not, still the same mpg.

Originally Posted by jim_mcglynn

hmmm. I have noticed an audible & revs change around 2100rpm to 2000rpm, but assumed it was VIS motors doing their stuff. So, is this the lock then, do you reckon?

Yes, that is the moment when your gearbox is locking. Power Vis motor starts kicking in when you are around 3000rpm, at that time you should feel a sudden improvement of power. Other members claim you can’t feel that point while driving with an auto gearbox, but I can feel it good in mine.