Vibration under load

[hotqld]

Any ideas on these symptoms

Travelling at 100k after 10 klm just under load
Heavy vibrations coming from transmission and dash for a couple seconds
At the same time revs increase from 2300 to 2400 and goes up and down.
Take the acceleration off or increase power and it goes away.
Gets a lot worse when towing.
New diff mounts front driveshaft rear CV joint.
transmission mounts look fine.
Topped up transmission fluid was a bit low still fairly redish clear not burnt.

Its kind off like a clutch slipping but then you expect to get worse under power.
Thinking about dropping the transmission sump to see if any filings in it.

Ideas? we are touring 3000kg caravan ....about 500 klm back home.

[WHHEMI]

Might be the lock up clutch in the converter, do you have a tow/haul botton. Do you tow in top gear.

[Clarky]

Does it behave like this?
http://www.atraonline.com/gears/2010...3/2010_3_8.pdf.

[ren0vator]

Originally Posted by hotqld

Any ideas on these symptoms

Travelling at 100k after 10 klm just under load
Heavy vibrations coming from transmission and dash for a couple seconds
At the same time revs increase from 2300 to 2400 and goes up and down.
Take the acceleration off or increase power and it goes away.
Gets a lot worse when towing.
New diff mounts front driveshaft rear CV joint.
transmission mounts look fine.
Topped up transmission fluid was a bit low still fairly redish clear not burnt.

Flaring clearly points to transmission issue
Transmission fluid not burnt?
First guess is a line pressure fault

Could well be a TCC problem

[hotqld]

Thanks Guys,
Friday I dropped into a mechanic in Ballina ..friend of the family.
We dropped the transmission pan...a lot sludge around the magnet (probably due to towing the fluid was 18,000 k old a little dirty but not burnt)
6 or so silver specs ...that was of no concern.

His diagnostic is valve body or torque converter.

Changed the fluid, new filter and a anti shudder additive which he says he has had great results with but doesn't allways work.

We towed 60 k 3000kg caravan and shudder is 90% gone, the mechanic said it normally takes 500klm for the additive to work 100% at which stage add another if there is still minor shudder...so fingers crossed seems amazing stuff.
Will carry on touring as planned and will probably run up close to 500klm.

If this does not work, its off to a transmission specialist for a second opinion
Valve body or torque converter

[ren0vator]

From Allpar explaining TCC symptoms:

Paul Knisely helped a reader whose W5A580 was making a vibration and low-frequency noise in drive, with the MDS activated between 18 and 50 mph. Four different dealerships had said that the system was working normally, and suggested driving in fourth gear to avoid overdrive. Paul checked the problem with Alldata DIY and found a diagnosis that the clutch in the torque converter was not holding — showing it was, but not actually holding. This would cause the vibration.

[Clarky]

No MDS on the CRD only the Hemi.