bradqui

Hello! My 2009 R350 4Matic has been experiencing shuddering between 2000-3000 RPMs in all gears. Lower RPMs are smooth, and it smooths out again above 3000 RPMs. I have completed a few repairs trying to address it, thanks to the helpful people in these forums and online. The repairs I have done so far:

1. Motor mount replacement (both driver and passenger sides)
2. Transmission mount replacement
3. Transfer case chain replacement (This did fix a chain slippage issue, but not the shuddering)

What else should I be looking at in order to troubleshoot this further? I did the above repairs myself, and I'm trying to avoid going to the mechanic since I have four hungry mouths to feed.

Thanks in advance!

Brad

chassis

Driveshaft center bearing? How do you perceive the shuddering? Where do you feel it? Where do you hear it? Does it change intensity with more or less throttle?

bradqui

The shuddering feels very central and definitely is affected by the amount of torque going to the wheels. There's not much sound to it. It gets more intense with more throttle until it smooths out above 3K RPMs. Cutting/lowering throttle while it is happening will cause it to stop happening even if the RPMs are in the right zone. It definitely seems related to the level of torque.

chassis

Driveshaft center bearing, it's a normal wear component at higher mileages/ages.

bradqui

Thanks for your input on this @chassis, it is much appreciated . This makes a lot of sense. Researching a bit, it looks like I should probably look at replacing the flex disk as well. The flex disk is easy to find online, but it looks like it is damn near impossible to get just a replacement center bearing. I'm starting to squirm a little bit because it seems like it may be calling for an entirely new rear prop drive shaft assembly. So my next question: If I buy a complete prop drive shaft assembly (either new or salvaged), will the shaft be balanced as a complete unit, or will it need balancing when installed into a different vehicle?

Thanks!

chassis

Replacing the flex coupling is a good choice. It is rubber, and nothing plastic or rubber lasts forever. Don't know about the propshaft balance question.

You could install a new flex coupling and rear prop shaft yourself, and take it for a test drive. If there is no vibration, job done. If there is vibration you can:

1. Take it to an independent shop for balancing
2. Use the "hose clamp trick" to balance the driveshaft. Google it.

The option you choose depends on how you want to maintain the vehicle, and your budget.

jneal3110

Torque converter; mine had very similar symptoms, have about 180k miles on it. I found a guy on eBay (starparts777, in Chicago) who rebuilds torque converters, had mine removed and sent to him, rebuilt it for $231. My indy mechanic charged $1000 for removal, shipping, reinstall, and basically hoist rental for the four days it sat waiting. Runs perfectly now, smooth as silk.

chassis

bradqui, any updates?

bradqui

I haven't done much on this yet as I have not had time to do the needed research. Since now I have two different possible problem points, I may need to take it into an indy to see if I find the root cause for sure. I appreciate your guy's help, and will update this thread once I have new information.

Thanks!

Mfbr320cdi

Try changing the trans fluid and filter, mine was doing this as well. My fluid was dirty and wore and I'm sure filter was no longer working. I did it all myself its really not that hard if you want to save yourself some money.

jneal3110

This did help a little with mine but the improvement wore off in a few weeks.

bradqui

@Mfbr320cdi I performed this maintenance this weekend and the shuddering is almost completely gone! My torque converter didn't have a drain plug so there is quite a bit of bad oil in there still. Once it mixed with the good oil and run through the new filter it seemed to smooth itself out. I think I'll do another fluid replacement in 5K-10K miles to get more new fluid in the system. You win the internet for the week! Thank you for pointing out to the world my failure to perform basic routine maintenance...

bradqui

Were you able to drain the torque converter on yours? From what I read, most of the 722.9 transmissions have a TC drain plug -- I just happened to get the short end of the stick as I looked for a long time to make sure I didn't have one. I could see the issue cropping back up soon if the torque converter isn't drained since nearly half of all the fluid in the transmission is held in the torque converter.

jneal3110

Actually I can't say for certain that the mechanic drained the TC when he did the flush/filter, but I would have thought that's standard operating procedure. He's done it a lot, I just assumed doing the TC was part of the flush.

sweins

Have only recently noticed the shutter in 3rd gear between 1500-2000rpm. Going to change the transmission fluid, filter, gasket and service the valve body solenoids with new orings using this kit. https://cobratransmission.com/722.9-Solenoid-Oring-Kit
From what i've read on other forums about these transmissions, it's a good preventative measure. Over 200K miles, they become quite deteriorated. Deterioration is acelerated if the torque converter is locking properly allowing for increased slippage which creates heat. Will update this summer when I tackle the job.

Jamie Berenbaum

So i am having the same problem and then BOOM, my car died
When i crank it, the motor feels like its rocking from side to side.
Not happy and afraid going to cost more than the car