Project Chronicle

I had a sneaking suspicion when the 500E arrived that I was due for transmission trouble. The seller was an honest guy, but it seemed he was in the camp of being able to live with some flaws that I wouldn't be able to abide.

The 722.365 automatic transmission found in the 500E is used across the W124 lineup. It's a fairly reliable transmission but does have a certain life expectancy. The tell-tale sign is longer and longer engagement to go into reverse. Two seconds is normal; anything longer is considered indicative of the gearbox being on its way out. My delay was about 4 seconds. 

We did a bunch of work hoping to remove any doubt about the transmission. The transmission bushings and differential "guibos" were all replaced to tighten up the gearbox action. While the shifter moved more confidently through the gate, it did nothing to address the delay going into reverse. 

No dice. So, after weighing a transmission rebuild, we bit the bullet and ordered a rebuilt transmission from Sun Valley, a known rebuilder of Mercedes gearboxes. It's on order and will be installed in the coming weeks. While unfortunate, it will be a major value add to the 500E's future price tag.

The progress on the 500E has been slow, but I'm not terribly worried; there's been no ugly discoveries at the moment, and it seems like my fears about transmission issues are unfounded. Most of the issues with regards to slow shifting and noises in reverse have nothing to do with the transmission itself but rather heavily worn rubber components that help to support the transmission and driveshaft. 

Knowing that the transmission itself is likely fine is a major win. In addition to the shifter bushings, the transmission mount itself is very tired; both "guibos" on the driveshaft are heavily cracked and overdue for replacement; the noise heard in reverse was actually an insulation pad that was dropping down and rubbing on the driveshaft; ball joints, steering linkage, and the lower control arm bushings, all shot; and the shop also discovered a long-festering fuel leak coming from the charcoal canister in the driver's side wheel well. 

Right now, the exhaust and the driveshaft are dropped in preparation for repairing all that I just mentioned. Once we're through that, we'll see how much the drive quality has improved and what may need to be done next.