98 E320 won't shift out of second gear
 

A gentlemen said he purchased the car in good working order and it sat awhile, he drove it around the block and stayed in second gear and it's been sitting since. the local shade tree mechanic suggested just drain the tranny and replace the filter to see if it clears up. I've worked on older model cars 60s- 90s, anybody see this in the six cylinder 320s? this almost sounds more like an electrical problem

sounds like the transmission is stuck in mechanical limp mode, Check the ATF level with a 722.6 dipstick (it does not come with the car - you need to buy it as a tool)

if the level is good and the ATF is correct type and you still get hard shift from N to D with clunk and stuck in 2nd gear only, a deep level scan is needed to isolate the issue, usually its a conductor plate gone bad (broken speed sensors), after replacing it the only way to clear the transmission computer codes is with benz capable deep level diagnostic tools which connect to the 38 pin connector in the engine room fusebox.

There's a DIY here that might be helpful =>

PeachPartsWiki: 722.6 Transmission Fluid and Filter Change

The 722.6 is electronic shift, you need to scan the transmission module for codes. Changing the fluid isn't going to fix anything.

A common failure point is the input and output sensors on the conductor plate. ( top of valve body, easy to change. )

Another common point is a leaking trans adapter plug / sleeve. You might not see a leak on the ground, but an o ring can fail, oil gets wicked up the wires to the trans controller. The controller can be cleaned with electronic cleaner.

Is there anything strange happening with the dash / fog lights ? I have a 97 E320 ( inline 6 ) that I'm using for parts. It is stuck in 2nd, high beam light on dash comes on,some warning message in the dash and the left fog light stays on. Once it returned to normal and shifted fine. I'm thinking a common ground has corroded and a few circuits are seeking each other for ground. ( MB puts a pile of grounds on a single bolt, this reduces ground loops but can cause all sorts of odd behavior when the stack becomes ungrounded. )