Join Date: Nov 2009
Location: United Kingdom
County: Greater Manchester
5th/6th gear shudder at 2000rpm
For anyone experiencing similar problems
Here's the car:
2.4JTD Diesel 6 gear Brera 2006, driven a combo between bruning petrol and economising. 80% motorway driving, often shifting into higher gears as you're 'supposed to'.
Here's the scenario:
When getting onto the motorway, hitting 60-80mph and switching up to (4th) 5th or 6th gear, the car judders and shudders at approx 2000rpm, and doesn't want to shift PAST 2000rpm for a while. Either you drop down gears to feel comfortable driving, or you persevere and accelerate through the shudder until it goes and the revs increase.
Scary experience at 80mph in the outside lane!
Here's what the kind folk at MVC in Sale, Manchester said to "save me a possible bill"
The Brera was invented with a 'regeneration' feature, whereby after a certain amount of miles, the exhaust would 'clear itself of gunk' by burning it off at a certain combination of mph/heat/etc. That can kick in at any time, and the engine has to go through that to clear the gunk.
However, because the car is driven on the motorway at such cruising speeds shifted quickly to 6th gear so often, it never reaches that heat/torque required to burn it off, meaning it stays cloggy. The guy recommended 'burning it off' by doing a few miles on a quiet motorway in lower revs (3rd or 4th - still before red-lining) at approx 70mph. I may feel it a little, but go through it and it should clear it. also recommended I wasn't so quick to shift up gears (keeping the car around 2000rpm too often) as the 'regeneration' would have difficulty kicking in.
Drove home doing precisely that and will see how this fares....
Alfa Romeo Brera 2.4JTDm, bought with 29k on the clock, Nov 2009