Well got almost 1,500 miles on my new rebuild, second oil change and she’s running
strong and taint used enough oil to even mention. Real happy with the 216, she pulls
strong and runs nice and smooth.

Even though it was nice and tight and not making any unusual noises and really didn’t
show any signs of wear I chose to rebuild the SM420 at the same time. Seemed like a nice
idea to start out with a completely new drive line from the fan blade in the front to the
differential cover in the rear. I used a Novak‘s parts kit for the rebuild, and the gear box
was in excellent condition, absolutely no sign of wear anywhere. Thinking I wanted to go
first class with everything I opted to refill with Mobil Delvac Synthetic Manual
Transmission fluid 50 for extended drain use. This was recommended as it was being
used in a fleet of over the road trucks with manual transmissions

After driving her for a couple of months now I have one thing that’s really buggin’ me.
Shifting from 3rd to 4th before the rebuild was silent, never had a problem with the syncro
catching up. When I brought her home 8,000 miles ago I flushed and refilled with Citgo,
Mystik JT-7 85w-140 gear oil which I’d used in synchronized manual transmission for
decades before. Now with the Delvac Synthetic oil the syncro is having a hard time
keeping up with the gear change. It’s fine if I shift real sloooooooow or double clutch but
a normal shift almost always get’s a tooth or two.
I
’m thinking more and more that the synthetic with it’s increased lubricity is the cause of
the syncro ring not grabbing the cone like it did before.
Driving season is about over for me and Bluebelle. I’m putting her down as soon as the
snow and salt starts to fly. So I’ll be draining the Delvac synthetic and refilling with my
old standard JT-7 for the 2012 season.
Any thoughts on this or better yet any personal experience?

Denny Graham
Sandwich, IL

Last edited by Denny Graham; 11/30/2011 2:59 AM.
Denny G
Sandwich, IL