Have you replaced the tires recently? I have an 88 GLE wagon and have had a couple of types of tires cause similar symptoms - back seems to lag front then sway out, especially on freeway entrances. I had a set of Pirellis that were very bad. I now have Uniroyal that do the same thing.

'88 745 GLE at 246,000 miles

I just completed some front end work on my wife's 88 740GLE non-turbo earlier this year. It needed ball joints, strut rod bushings (cone bushings) and one sway bar end link had broken.
Last things first- that end link can certainly cause a very uneven left-to-right feeling in the steering. The left one in mine broke a few years ago, and the right one was found to be broken after a long trip this past December. It wasn't so much a wandering sensation as it was almost an instability of the car when taking a moderately hard turn at speed. This was compounded by a significant shake when turning right at most any speed. Note that the end links come in two styles, one being a straight bolt and the other a bolt with a ring at the end- be certain which kind you've got before ordering any replacements. I used the polyurethane bushings and I think they were VERY difficult to compress enough to install. Did eventually get it together though.
Due to the design of the front suspension on these cars, it can be hard to diagnose a worn component- even when the car is raised up, the ball joint tends to stay in compression, so the only way to be certain is to push on things with a pry bar. Any play in the ball joints indicates replacement. They're not difficult, though you WILL need a "pickle fork" ball joint/tie rod removal tool. It's a tuning-fork shaped wedge that you hammer in to release the tapered bolt that locks the ball joint in place. The nuts and bolts otherwise are easy enough to get out with a regular breaker bar and/or 1/2 inch ratchet. I found I needed a length of wood or long bar to press down on my control arm to get the strut away from the ball joint. Not hard to do but a second pair of hands would be helpful here.
For the cone bushings, probably the single most common part to wear out on the car, you need 4, and they're pretty cheap. Impact tools are nice for dealing with the large suspension bolts, but they're not necessary. Replacing these also helps prevent front brake rotor warp- another common problem.
See FCP Groton's page for good info and a diagram:
www.fcpgroton.com
--
Rob Bareiss, New London CT ::: 'Roterande Fläkt Och Drivremmar!'

At 180K you probably have, as Steve points out, considerable wear on some or all your front end components especially if they are the origionals. The FQAs walks you through everything on the front end and FPCGroton will make sure you get the right parts with good pricing. Depending on you skill level and what you have toolwise, you can do a lot of it yourself as it is pretty straight forward but you're dealing with large bolts that are very tight and having a large impact wrench sure makes life a lot easier. You may or may not want to tackle changing the front struts which requires a spring compressor. This is dangerous work if you don't know what you're doing or are careless.

bl

Worn front suspension parts: you likely need shocks, bushings, and ball joints. See the FAQ.