I have been noticing a low groan when taking off from a start. I don’t really hear it at idle and it’s not annoyingly loud yet. 2013 with 107k miles. I immediately thought of a power steering power with low fluid, It’s topped off and has been sucked out and replaced with CHF 11S (I recall). Transmission was serviced at 100k. Water pump has been changed.
Haven’t checked the diffs or transfer case yet. Could be wheel bearing, front diff.....but it’s not really dependent on turning vs straight.
Anyone have a similar experience with resolution?

 

Its really hard to tell what a noise is, without being able to hear it. But based on what you said, I have a few observations:

1) suck out all the 11S and replace it with CHF 202. Although they are compatible, CHF 202 is better suited as a Power Steering Fluid. And is often upgraded from 11S to 202 for noise complaints.

Diff and Transfer Case fluids are due every 75k. I see T/C shudders occur and need fluid change before the recommended 75k. Frequency and correct fluid is critical with the T/Case.

Transmission serviced at 100k? Hopefully by somebody who knows what they are doing. We often see "cold start" whines and slipping because the shop didn't know the vehicle had to be running to fill it. So they fill it with car off, until it pukes out the fill hole and caps it off. Then there are noise and shifting issues until the fluid heats up and expands, reducing the symptoms. Hopefully they used ZF LG6 fluid.

To rule out a belt driven accessory, you can always pull the belts off and drive it. Best to do it while the engine is cold, since the water pump won't be spinning. This will rule out A/C compressor, water pump, alternator, power steering, fan bearing, etc...

 

Thanks for the response and advice, the 202 is harder to find. I’ll just order some on Amazon. The trans was serviced by a reliable/knowledgeable Indy whose name you would recognize. Prior owner says he’s serviced the diffs/t-case, but I didn’t receive any supporting documentation. I’ll probably order the kit from British Atlantic just to be sure.
Do you like any Power steering additives (not leaking) to condition the pump? Have you seen any pumps go out?

Great tip to pull the belt!

 

We see ZERO pump issues and therefore install NO additives.

Also, taking the belt off will rule out a fan hitting the shroud. If the fan shroud wasn't put back together properly, the fan could be making contact under acceleration (this is more pronounced when a motor mount is bad).