Shudder continues. Has anyone found out what might be the solution?

I have the same problem....took car to dealership. Let mech drive and experience shudder. They installed new software for transmission. Car still shudders at 40 mph while lightly pressing on gas pedal. They also said I have a cracked "Sub-frame bushing". I will replace. If shudders continu...

took car to dealership. Let mech drive and experience shudder. They installed new software for transmission. Car still shudders at 40 mph while lightly pressing on gas pedal. They also said I have a cracked "Sub-frame bushing". I will replace. If shudders continues, back to dealership.

I received a message " Transmission Service Required". It's at a mech shop now. I'll post what he says the problem is. Before he mentioned a transmission relay not putting out enough pressure.

Checked mounting bolts and bushings..everything is fine: however when on road, car still shudders at low acceleration to 35 to 40 mph, only. When I'm on the open road or the highway, no problem. In the city or going slightly uphill, it seems like it is coming from transmission.

Thank you for the reply. Hopefully I can reach these mounts myself. The engine does seem to vibrate more when I put it in reverse.

It only happens between 35 and 40 mph and it last 2 seconds then smooths out. Otherwise it runs perfect no shudder.

Greetings,
I am new to this forum. I have a 2006 S60. When I slowly accelerate to 40 mph, the engine shudders for a second, then smooths out. I filled up my gas tank with a higher octane fuel, still shudders. What else would cause this. Plugs? Transmission?