W124 - Autobox flaring

[julesg007]

Hi,

Would appreciate some guidance on the above mentioned problem.

I have seen the term "flaring" used on a few occasions and would be very grateful for an explanation as to what it actually means as I have not owned a car with an autobox.

I also saw the following statement, "the problem can be fixed by changing the transmission fluid", is this case or is flaring the begining of a serious gearbox problem that will be expensive to fix?

Also, as all my cars have been manual, when driving (say a test drive) how can you tell if an autobox is flaring?

Thanks again for all the help.

Have a good weekend
Regards
Jules

 

[television]

Flaring is when the engine speed changes and the car speed is not,,or when the car changes say from 2-3 the engine speed varies or increases before the change takes place. in a nutshell the engine does not feel directly coupled to the car.

Often dirty fluid or low on fluid, and very often on a 124 the vacuum pipes off or damaged.

You too have a good week end

 

[stumo]

Yeah as television said, that is flaring. If it is happening, it is usually detectable on upshifts only.

It would be kind of like if you changed gear (upshift) in a manual with your foot still on the throttle a bit, the engine rpm would increase during the gear change, then drop back when the new gear and clutch is engaged. But with flaring you wouldn't get that little surge of power you would get on a manual when re-engaging the clutch in this situation.

In a good modern auto box, the rpm should remain steady (or drop slightly) during the upshift, then obviously drop further once the new gear is engaged. It should be very smooth and quick.

if you are looking for your first auto box car, I suggest you test drive as many as possible to get a good feel for it, or get it professionally tested. Auto boxes are very expensive items to fix, but they do last a long time if propely serviced.

 

[Number_Cruncher]

An oil and filter change for the gearbox is a good plan, but, if you're concerned about flaring on a W124 automatic gearbox, there is an easy first check to make.

Find the vacuum pipe which goes to the modulator valve on the gearbox, disconnect, and plug its end. If when you drive the car now there is no sign of flare, then, the internals of the gearbox are OK, and you may need to check the vacuum system, and possibly adjust the modulator pressure.

If, however, you still get flare, then the gearbox is worn internally, and will only get worse, adjustments to the modulator pressure to firm the changes may help things temporarily.