I own a 1990 300SEL with the 722.351 trans. The transmission is ready for a rebuild but I would like to upgrade it to handle the additional power of the Mosselman twin turbo I will be installing. The power rating of 300 HP puts it in the ball park of a V8 load on the trans.

What I would like to do is convert it to a 722.350 configuration as fitted on the 560 SEL of the same year. The problem is I have been having trouble determining the differences in the internal hard parts, e.g. drums etc, that I need to accomplish the upgrade. I already have a 1st gear start valve body that also has a shift kit in it so I'm OK there.

The other question I have is that the trans whines (not loud but noticable) in second gear only. Other than that it shifts fine. Any ideas what would cause this condition?

Thanks,
Motor Head