95 E420 Trans does not reverse.

[420eagle1]

Hello everybody, I will appreciate very much your valuable advice on my 1995 E420. About a month ago I got the Check Engine Light after doing the oil change. The engine started to idle erratically up and down when gear selector was in Park or in Neutral position, but when in Drive position the RPM is normal. Drove the car to an MB shop to pull the codes and this are the ones that pull out:
006-ISC / 005-EGR / 004 Secondary Air Injection --> LH1-SF1 /
017 Control Module CC N4/3 / 080 Stop lamp Swicth S9/1 / 096 Starter Lock-out/back-up lamp switch S16/3. While pulling the codes the tech informed me that there were 2 vaccumm lines damage right above the Right Distributor cap and actually, one line was not even there. The tech erase the Check Engine Light and said if the light comes on again come back to shop one more time to pull the codes. Drove the car home and fixed the Vac - Lines, and bingo the RPM was fixed about 95% even on Park and Neutral. The up-down RPM is mild and actually it fixes by itself.
Then, 4 or 5 days later, the Check engine Light is back! Only for a couple of days, then it turned off again and it has not come back in more than 2 weeks.
Now, yesterday drove to the supermarket and when put the gear selector in Reverse it felt that the tranny engage the gears but do not reverse. I inicially thougt that the emergency brake was on, but was not. So, I tried to push a little harder on the accelerator and I got it to move. However it felt like I was pushing a concrete wall. I drove it driving forward.