Could a faulty alternator affect the performance of auto gearbox?

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01alam

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Oct 3, 2008
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143
Hello all,

I just realised my alternator may not be in the best of shape, it is working but not very well. Would like to know if anyone had any experience with alternator affecting performance of auto gearbox? Bearing in mind that it is a 1970s auto, it might be a bit different then.

Further to that, just wondering if anyone had fitted a Cherrybomb to a M110 engine? Saw a video on youtube: http://uk.youtube.com/watch?v=7dsnsVZL58I Sounds rather interesting and quite tempted.

Angus
 
Have you checked the voltage at the battery when the car is running ? It should be around 13.6 volts . If the reading is under 13 volts then it could be the alt. if the reading is between 13.5 and on more than 14.5 then the alt is ok
 
I don't see how a dicky alternator can affect the operation of a 1970s auto-box.
Even if you disconnected the alternator connector, I can't see it making any difference.
When the alternator is connected to the battery, the battery smooths out ther irregular full-wave rectified output from the alternator, and the battery charges at the same time.
So - An unreliable alternator output is not likely to make much difference.

I guess you've checked the transmission fluid level at the correct operating temperature.
Be sure that it has the correct grade of fluid and that it has been changed recently.
There will be a filter to change as well
Do not add any additives.

If all this is done, I guess that a clue to the problem may lie in the words "1970s auto".

What actually is the auto-box problem ?
Is is flaring on changes or a bit erratic or bumpy on changes ?
It could well be a tired auto-box.

Fixable .... Not a job for an amateur .... Could be expensive.

If you've tried all the above, I suggest you get a MB Indie Specialist or an auto-box specialist to check it out.

Cheers.
Johnsco
 
Have you checked the voltage at the battery when the car is running ? It should be around 13.6 volts . If the reading is under 13 volts then it could be the alt. if the reading is between 13.5 and on more than 14.5 then the alt is ok

The reason I am suspecting there is a alternator fault is because when I drive along the lights are brighter and the indicators are flashing faster, but when I stop and put it in neutral the lights are dimmer and flasher is slower.
 
I don't see how a dicky alternator can affect the operation of a 1970s auto-box.
Even if you disconnected the alternator connector, I can't see it making any difference.
When the alternator is connected to the battery, the battery smooths out ther irregular full-wave rectified output from the alternator, and the battery charges at the same time.
So - An unreliable alternator output is not likely to make much difference.

I guess you've checked the transmission fluid level at the correct operating temperature.
Be sure that it has the correct grade of fluid and that it has been changed recently.
There will be a filter to change as well
Do not add any additives.

If all this is done, I guess that a clue to the problem may lie in the words "1970s auto".

What actually is the auto-box problem ?
Is is flaring on changes or a bit erratic or bumpy on changes ?
It could well be a tired auto-box.

Fixable .... Not a job for an amateur .... Could be expensive.

If you've tried all the above, I suggest you get a MB Indie Specialist or an auto-box specialist to check it out.

Cheers.
Johnsco

Cheers, I have booked it in for a service in West Mosley at an Indie that was recommended by many here. Doing a full service and a gearbox oil change, hopefully will imrpove after that!
 
The reason I am suspecting there is a alternator fault is because when I drive along the lights are brighter and the indicators are flashing faster, but when I stop and put it in neutral the lights are dimmer and flasher is slower.

That's not at all unusual.
Many cars do this on tick-over, because the alternator (belt-driven from the crank-shaft pulley) is running more slowly.
As long as your red light is not coming on at tick-over, there's probably nothing wrong with it.

Johnsco
 
Cheers, I have booked it in for a service in West Mosley at an Indie that was recommended by many here. Doing a full service and a gearbox oil change, hopefully will imrpove after that!

Let us know if it improves.

If the problem is just slight-flaring on the auto-box, it might run like that for a very long time without giving you any serious trouble (unless you are in the habit of really-hammering it ... Which I suspect you are not)

Johnsco
 
The reason I am suspecting there is a alternator fault is because when I drive along the lights are brighter and the indicators are flashing faster, but when I stop and put it in neutral the lights are dimmer and flasher is slower.


That is proof that the alternator works, and a good indication that the battery is on the way out.
 
One electrical problem which would perhaps effect gear changes INDIRECTLY is if you have a dodgy earth engine strap. These can rust thro or corrode at the end contacts. An engine on "tired" mounts may move quite a bit during gear changes which could lead to momentary loss of electrics as earth contact is broken and then connected again. Lots of older cars have problems with electrics which are down to poor earthing So check all those earthing straps/cables/ chassis mounting points.
 
The reason I am suspecting there is a alternator fault is because when I drive along the lights are brighter and the indicators are flashing faster, but when I stop and put it in neutral the lights are dimmer and flasher is slower.

What's that got to do with the gearbox.?
 
Hi all,

Had it serviced and its much much better now, doesn't seem to be the alternator at all, its runs fantastically, which is great.

Cheers
 
Did they identify what the problem was ?

Johnsco
 

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