From: rumbleseat Sent: 8/16/2002 10:59 AM
(1) Flat towing with the driveshaft turning in neutral. The main shaft of the trans turns, but the cluster and main drive gear do not. This makes the front of the main shaft rotate in its caged bearing in the inside of the main drive gear. Second gear is engaged in the cluster, but is not engaged in the rear main shaft.... so second gear does not rotate but spins on the rear main shaft. There isn't any bearing between second gear and the rear main shaft.... only a copper/brass bushing. This should shorten the second gear bronze bushing life considerably and possibly seize when towing. Going further.... the low reverse slider is in the neutral position (between low and reverse gears on the cluster), and turns with the main shaft via teeth on the main shaft. So it doesn't have to slip like second gear does. Now the problem as I see it surfaces. Visualize what will be turning inside the trans while being towed. The cluster gear won't be turning...... and that's the problem. The cluster is immersed in gear oil and distributes it via gear teeth and/or spraying thoughout the trans. Right..... the gear oil level is too low to be picked up by the cluster and main shaft gears. So the main drive gear bearing the rear shaft rotates in doesn't receive gear oil. Right.... it'll burn the bearing. There is some oil splashing around that may reach this bearing, but not nearly enough.
Flat towing with the clutch depressed and in neutral. Same problem with the oil level since the cluster is not turning. Maybe leaving the trans in high would work since the cluster gear would be spinning. However, the clutch throw out bearing must turn constantly. Most throw out bearings are not a full time bearing. Consequently, it'll fail. Not a good idea, in my book, if you're towing for several hours/days. I'm uncertain if it would have any effect on the clutch pressure plate springs since they may weaken from being compressed for such an extended period??????
Possible solution? Tow in neutral. BUT fill the trans almost a pint over full so the main shaft is in contact with gear oil. Second gear will now do the dispersing of oil. We did this when flat towing stocker cars out of state. We wouldn't drain of the excess but just race with the higher oil level. We also did the same to a couple of early drag racers with no problems when towing out of state. When the trip is over and you're going to drive it everywhere, just drain off the excess gear oil.
As always, this is just my thoughts on the subject..... rumble seat