450sl Transmission rebuild or exchange?
 

Have an automatic 78 450sl with intermittent slipping between 2nd to 3rd and 3rd to 4th gears. Fluid clean, I beleive it is just its time.

However, I can buy a rebuilt unit and torque converter for $1500 (excluding shipping of $150 for rblt unit and another $150 for core return). Total would be $1800 before install.

What is shop time for an install? I have been quoted $2200 to $2500 for rebuild, including refurb of the TC from a local shop. Do I save any $ having them install a rebuilt unit I purchased the parts, or letting them simply do the rebuild themselves. Not knowing the install time, seems it would be close to the same cost.

Any insight appreciated.