Just fitted a secondhand R380 to my 99 d2 only to find that first seems to have been abused somewhat over the years and the syncros maybe a bit worn. The box that I took out had cooked a bearing over 3 years ago and at which time I filled it with Moreys oil stabilize and continued to put more than 20thou kilometers on it.

Question I have is it a good idea or worth putting a additive in the box to improve the shifting in first and what would be a good additive.

Running the recommended Penrite oil for the box at the moment..