What's involved in an update to 90+ W124 transmission?
 

I have an '88 300TE transmission that has an engine whirring sound to it. I've replaced the oil, filter, and K1 springs so it shifts fine but the noise remains and I'm afraid it can fail at any time. It only slipped once because oil was low. The engine is a 3.6L with more torque.

I'm considering:

* finding a '90-92 transmission with first gear start. What are the differences and will they retrofit...easily? Are these improved or stronger?
* rebuild a spare '88 transmission

Upgrade Transmission
 

Supposedly the 500E trannys have more strength.

Memeber Jhodg5ck has suggested replacing parts with the 500's.

your links didn't work but I found some of Johnathan's threads:
http://www.peachparts.com/shopforum/showthread.php?t=209138

http://www.peachparts.com/shopforum/showthread.php?t=108062