I ran a little in my Getrag 5 speed behind my Cummins. I changed the oil, added the Lucas Oil treatment, to the specified oil for the trans. After that the trans shifted horribly, and was far more noisy. I ran it a while like that and it did not get better. I drained out the oil and as much Lucas as I could get out of it. I then refilled it with specified oil and ran the trans went back to shifting nice, and no more noise. Ran it a long time with lots of heavy loads, lots of tire chirping, speed shifts and such before the output shaft bearing finally became pitted and noisy.

I've since rebuilt it with new bearings, and filled it with synthetic oil, and had great service.

No Lucas for me.....

Michael