hello all new to this group,and i have a question on a 1972 postal jeep ,4cly chevy 153 with a 2sp powerglide .will it be harmed by flat towing it the 75-100 miles to its new home.i have heard that older auto trans can have damage done because the pump is not turnning ,can any one explane what will happen ?or is it best to remove drive shaft thanks for any help gary foster
That is what traditional wisdom specifies. Apparently some transmissions had pumps that would be activated by the driveline and provide needed lubrication, but most of that day probably didnt. Without researching which are which, I would say it is so easy to disconnect the driveshaft in most cases that I would do it as a matter of precaution.
Most automatics cannot be towed more than 30 miles at speeds under 40 mph without risking damage. Powerglide included, if I remember right from my '67 Chevelle's owner's manual. Drop the shaft.
Damage can occur during towing because of residual friction in the multi-plate clutches of an auto trans. Even when "disengaged," multi-plate clutch disks rub lightly against the plates and also generate heat by shearing the fluid between the plates and disks. That's not a problem when towing across town or below highway speed, but a sustained high-speed tow can roast at least one clutch pack. Older automatics (for example, Chrysler Torqueflites prior to 1966) have both an engine-driven pump AND a driveshaft-driven pump, so that even with the engine off there is a flow of fluid through the clutch packs to keep them cool and lubricated if the driveshaft is turning (and you can also push-start those cars because they'll engage the clutches and turn the torque convertor when pushed). Later transmissions deleted the rear pump because in 99.9999999% of all the car's life, its nothing more than a waste of power. The compromise is that you can no longer tow them "dinghy style", and you can't push-start them.
Agreed. You may want to invest in a tailshaft plug for the transmission (cheap from your local speed shop) to keep from dribbling fluid when you raise the front of the car. Don't just wire the driveshaft up under the car, that's asking for it to fall off and get run over.
The driveshaft is very easy to remove, I would go that route rather than take a chance. You can just unhook the rear u-joint and tie the shaft up out of the way or remove both ends and take it right out.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: N>
Yes, don't tie it up, it can still slip out of the tranny and become a projectile...make sure you wrap that rear u-joint up with some tape, or the cups will fall off and your needle bearings go everywhere....
For the record, I believe driveshafts should be pulled when towing a RWD vehicle for any long distances. Now with that being said, I believe early Powerglides had the rear pump, later Powerglides did not. I haven't worked on one for a long time, so I can't tell anyone the cutoff date or if I'm absolutely sure on that fact. Anyone?
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