I hope you are kidding. 200K on an original transmission (and just losing reverse at that), is very good compared to any other average domestic or foreign car. It's pretty good for a W124 too. 180K on mine and reverse is still snappy.

Hmmmm...I feel fortunate then that mine is at 275k and the reverse just started to go :)

Well the odometer broke at 193K so I really have no idea how many miles were on it, but I figure it's in the 200K range. I did valve stem seals on it cuase it kept fouling #3 and took it on a 11 hour drive to W Va. and back with 5 poeple + luggage and except for being a little under powered (2.6L) it went up and down the mountians with the air on without a hickup. Then we gave it to my brother inlaw last summer and he has been driving it ever since. It just wants to go forever.

-Jim

i have the same issue on my 89 300ce,it had a delay going into reverse,one day the delay got longer and longer,to the point i have lost my reverse altogether,a mercedes specialist told me just from describing it,it sounds like the reverse piston has a hole in it,its not an easy fix,the tranny has to come out,he was telling me i need a complete overhaul for $2,000.00, i wanted to know why he couldnt just fix the reverse issue then he just hung the phone up in my face,imagine that,they think we are all loaded with money just cuz we own a mercedes-benz.im waiting on another shop thats backed up for like 1 month, he will diagnose it for free,then tell me if he can just fix the reverse,all my forward gears shift fine,the tranny fluid is brand new and smells very clean,blood red,i added lucas oil tranny conditioner and it didnt do anything.goodluck with your situation,its a real pain having to push the car and cut the wheel to get her to turn around,but if you park on a slight incline the car will roll backwards then you can shift into drive and it will be fine.

I think he's saying you've blown a reverse piston seal, which sounds right. It's just a couple hours of work but R and R the transmission is about six hours. Depending on your miles and plans it could be the wise thing to do. But nevertheless most shops don't want to do it - they want to do the full overhaul and you can't really blame them. They shouldn't hang up on you though - that's not a good sign.

Losing reverse intermittently ...
 

I have the 5-speed 722.5 auto box.

Cold, mine engages reverse normally.

Warm, it MAY not engage reverse; it just sits there but SOMETIMES will crash into reverse if I rev it high.

Hot, it usually engages reverse normally.

I aim to try a filter and box/torque converter drain and refill in the hope that might help.

I do feel somewhat pessimistic about this give the 230 K miles on the original box.

RayH