I have a 58 xk150 dhc with 4 speed. In first gear itI makes noise like a truck but drives fine and does not vibrate and the rest of the gears are silent. What is making that noise and what needs to be done to repair. I will appreciate anybody input and Thanks in advance. Michael Schenkman
dhc

Submitted by MikeEck@optonl… on Tue, 08/03/2010 - 13:00

It is difficult to answer your question because we can't hear the sound of your first gear. How familiar are you with the sounds of a Moss box? First gear is straight cut, which causes it to make a whining noise that the others do not. Depending on the severity of the sound, there could be nothing at all wrong with your transmission.

Submitted by bonnettoboot@e… on Sun, 08/01/2010 - 01:18

The noise described sounds like a bad bearing! But as it only happens in first, that would eliminate the countershaft/layshaft bearings, as the shaft is also used for 2nd & 3rd. Top uses the primary and mainshafts, so that eliminates the main front & rear bearings the only thing left that is used in first only, is the 1st gear on the mainshaft, these bearings are probably bad. Of course it doesn't really matter as the gearbox will have to be rebuilt antyway. The good news is, you can drive the car without 1st gear 99% of the time!

Submitted by SW03-09811 on Sun, 08/01/2010 - 00:21

Michael,
A 150 I had suffered the same problem. A trusted mechanic quickly diagnosed it as a worn "countershaft". (C.1856?) I believe this is a relatively common problem but requires removal of the transmission to replace the shaft.

Others may confirm this problem.

New shafts were once readily available. If you can't find one, let me know.

Good luck,
Dick