2006 XC90 Transmission vs Engine misfire

[VolvoGal01]

I have been to two repair shops giving contradicting diagnosis and no resolution.

If I am driving at least 60 miles an hour, and floor it to pass a car or go up hill I have an issue going into overdrive. If I am on a straight away, I hear it doing a grinding sound. If I am going up hill, it shutters/bounces. It has no issues in lower gears or flooring it at a lower speed.

This has not triggered any engine lights.

I CAN duplicate the issue.

General repair shop says it is the torque converter.
Transmission shop says it is misfiring in 3 of 4 cylinders, but I have 5 cylinders.... Hmmmm.

Help??

[draser]

They should provide some data to support their claims. For the torque converter, while it sounds plauzible based on your symptoms it's hard to explain the grinding you're hearing - unless the tranny is low on fluid in which case there will be other shitfting issues. Also, if it's indeed grinding did they check for metal specs in oil? For misfire there should be other computer live or stored data to confirm. If they did not present anything of the nature I'd get another opinion. And first thing I'd do for the sake of the tranny is to check fluid level and metal specs or burned fluid.

[huzzsaba]

Do a drain and fill of the transmission with the proper fluid. If 5 cylinder, just go to Toyota and grab 4 bottles of their T-IV fluid (you will use 3.5 litres) . This may solve your issue, otherwise it was probably needed anyways so its not like your throwing away your money. Drain and fill will cost you less than $40 if done by yourself.

Other things I can think of as far as shudder/bounce feel when going uphill is the boost pressure sensor. I never had a grinding sound but did have the rpms fluctuating when doing uphill and pushing on the gas and that sensor fixed it even though I had no codes.

If I were you, I would do these first:

1)drain and fill transmission
2)check all the mounts. a broken mount may cause the grinding sound feel.
3)replace the boost pressure sensor.

Lastly, please report back if you solve this issue so that we can learn from your experience.