[Sam1]

Hi all

2014 Diesel with 84k miles, ZF 8HP transmission.

I noticed recently, when coming to a stop at junctions / traffic lights etc, the down shift from 2nd to 1st is a little rough. I feel a bump or a jolt when 1st is engaged and car stops, rather than a normal smooth change.

All other function of the transmission in all gears and driving conditions is normal.

I intend to change oil/filter on the transmission, just wondering if anyone here had this experience, or if there is anything else I should look at besides oil service.

Thanks, Sam

 

[Mark301]

The ZF is usually trouble free, but of course anything mechanical can fail. Is the idle speed correct (not sure what it should be for the diesel) when in neutral ? Coming down through the gears (especially 2nd to 1st) if the engine RPM is higher than it should be you would feel a bump or jolt as it slows.

 

[Sam1]

Thanks Mark. I will check the idle speed when in neutral and feed back in this thread. It never occured to me to check.
When in gear and the car is not moving, from memory, idle rpm is around 800 on my Diesel.

 

[Sam1]

I tested the idle rpm in neutral and in other gears. It is steady at around 850. Fairly stable. I moved back and forth from fist to neutral to reverse etc. Steady at 850, no noticeable blip when I shift to neutral.

 

[Mark301]

I tested the idle rpm in neutral and in other gears. It is steady at around 850. Fairly stable. I moved back and forth from fist to neutral to reverse etc. Steady at 850, no noticeable blip when I shift to neutral.

Then I'm not sure Sam...the ZF I'll repeat is very reliable, but of course not infallible. Probably time to get it checked at a transmission specialist...it's not some thing that's necessary to use a Maserati service centre, unless it's under warranty.

Will be interested to see what they find.

Cheers...Mark