740 GL Auto, Gearbox not changing to 4th. Help.

[omega]

My Auto box on my 1990 740GL will not change into 4th. I have changed tho oil and the box is a lot smoother but still will not go into 4th. Could anybody help ?

Thanks....

[ancient_art]

Hi
I'm not the best to give you a possible solution to the problem but seeing that nobody answer to you yet , but they will for sure, I ll try to start at least with some suggestion . It's your gerabox the one with Drive and 3th 2 th and 1th ?or the one with Drive, 2th and 1th? becouse on the latter the 4th is allowed by a switch on gear lever pressing it a light on the dashbord goes away telling you that the 4th is free to be engage ,pressing again and light will come on telling you the opposite , could be ,if it is this kind of gearbox , that the switch is not working or just need to be pressed.
That all I can say l leave more thecnicality to better aknolewdge people that usually surfing in here.

All the best.

Gerry

[omega]

My gearbox is the one with Drive 2, 1, and the switch on the the gear stick. It sometimes changes into fourth but this is becoming less frequent, if you press the switch when it is in fourth it will kick down a gear and then revert when pressed again.

Thanks for your reply
John....

[ancient_art]

Hi again,
I have the same gearbox I usually leave the switch with 4th gear allowed all the time , bare in mind that the 4th gear is an overdrive so is working at high speed ,I need to be a least at 60 mph and on flat road to have it work otherwise the main gear is the 3th ,above that speed there is no problem to have the 4th working , but I make sure that does it by slyghtly lifting the foot from the gas pedal, if i don't do that at least I need to be steady with the gas to wait that the 4th kick in but if the road is a bit uphill this will not happen . To see if really work or not , disiengage the 4th by the switch and then take a drive around and see if anytime you go off the gas the car goes into 4th ( automatic gearbox as ours they do that )if you are not sure ,then block the gear in 3th , anytime you are without gas at 30 miles an hour look you revs counter, memorise at how many revs you are and then allowed the 4th gear and repeat it now if the revs are the same it does't work if they are lower ( quite a lot ) then everything is fine.
Make sure that you do not play too much with the switch and the gear lever one's in D you are fine use the lower gear only if You really need usually in very steep road going downhill to have some brake from the engine, block the gear in 3th without overdrive only towing a caravan and are at meantime on very bendy road.
If you are in everyday drive put the gear in D allowed the overdive (the 4Th) to work and not to worry about , of course if does not work probably is better have look at it starting from the switch itself , from more deep looking you must wait for somebody else who know better.
I apologise for my writing ,the english is not my first language ,and the writing as you can see is even worse , on the forum there is a guy ,Peter , he is from south wales and he has good knowledge he probably will give to you some advise .
The best luck.

Gerry

[omega]

Thanks for your reply, I'm from Yorkshire so I understand it perfect.
John.....