raybing Posted March 7, 2022 Share Posted March 7, 2022 Besides a broken axle why would the front drive not pull. Thanks Ray Quote Link to comment Share on other sites More sharing options...
doubleclutchinweasel Posted March 7, 2022 Share Posted March 7, 2022 Got any more information? Type of truck? Type of axles? Power divider or not? There are some great technicians on here, so the more info you give them, the better. 1 Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment Share on other sites More sharing options...
67RModel Posted March 7, 2022 Share Posted March 7, 2022 Pretty vague question.....in any live tandem axle setup the torque generated is always transmitted to wheel end with the least amount of traction. If that is enough traction to overcome the load then the truck moves. If not the wheel spins. If you engage the power divider then you force the torque into both axles, hopefully by doing this you can put down enough torque to get moving. With that being said the front drive doesn't necessarily transmit torque/power to the ground unless the power divider is engaged. Do you have a power divider? Is it engaged? On vendor axles like Meritor/Eatons it will be a manual air switch. A lot of the Mack tandems have an automatic "peanut" power divider that uses clutches. Please provide more information. 1 Quote Link to comment Share on other sites More sharing options...
raybing Posted March 7, 2022 Author Share Posted March 7, 2022 The rear set drives and both axles shafts are repaired. But only rear set moves truck Quote Link to comment Share on other sites More sharing options...
raybing Posted March 7, 2022 Author Share Posted March 7, 2022 Mack axles. I always assumed front axle set always engaged. Rear set drives with air switch Quote Link to comment Share on other sites More sharing options...
doubleclutchinweasel Posted March 7, 2022 Share Posted March 7, 2022 Are there any drive setups that use a "straight-thru" drive shaft (no inter-axle differential)? If so, then ANYTHING wrong in the front drive would cause it to do nothing, but still let the rear axle drive. Like, broken spider gears, side gears, ring/pinion. If there IS an "open" inter-axle differential in there, then a broken front drive should just allow the front driveshaft to spin and do nothing. In that case (with everything intact), if you jack up ANY wheel and put it in gear, that wheel would spin all day without the truck moving. That same setup, with an optional inter-axle differential lock, would give you the option of locking the IAD and forcing the rear axle to drive as well as the front. With some type of torque-biasing power divider (like what I suspect 67RModel is talking about), I suppose a broken front drive could still allow the rear drive to move somewhat, because of the effects of the "automatic" power divider. Still, more information as to exactly what setup is in there would help the guys on here narrow it down for you. What kind of truck is this even in? Pictures always help, too! 1 Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment Share on other sites More sharing options...
raybing Posted March 7, 2022 Author Share Posted March 7, 2022 Quote Link to comment Share on other sites More sharing options...
doubleclutchinweasel Posted March 7, 2022 Share Posted March 7, 2022 Sorry. Your last post came through while I was typing mine. Since it is a Mack setup, some of the guys on here will be able to talk in detail about the way it should work. Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment Share on other sites More sharing options...
raybing Posted March 7, 2022 Author Share Posted March 7, 2022 Rd 600 glider. 44000. I think Quote Link to comment Share on other sites More sharing options...
doubleclutchinweasel Posted March 7, 2022 Share Posted March 7, 2022 (edited) Can you jack up a wheel on the front axle, leave the rear axle on the ground, put it in neutral, and see what happens as you turn the driveshaft by hand? Edited March 7, 2022 by doubleclutchinweasel 1 Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment Share on other sites More sharing options...
Onyx610 Posted March 7, 2022 Share Posted March 7, 2022 Out of curiosity how do you know it’s not driving? 2 Quote Link to comment Share on other sites More sharing options...
doubleclutchinweasel Posted March 7, 2022 Share Posted March 7, 2022 (edited) 12 minutes ago, Onyx610 said: Out of curiosity how do you know it’s not driving? That's kinda why I asked that last one, O! Edited March 7, 2022 by doubleclutchinweasel Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment Share on other sites More sharing options...
mechohaulic Posted March 7, 2022 Share Posted March 7, 2022 air operated power divider. did you take the line off to see if air is coming through?? did you flip dash switch to send air through??? yes on both questions ; possible set screw backed off on slide fork. Quote Link to comment Share on other sites More sharing options...
raybing Posted March 7, 2022 Author Share Posted March 7, 2022 I can hear the power divider lock Quote Link to comment Share on other sites More sharing options...
mechohaulic Posted March 7, 2022 Share Posted March 7, 2022 clean around the small side cover plate (4bolts) remove cover . activate the switch== fork should slide . might have to jack up one wheel AFTER you block tires ;;spin the drive shaft. the rear rear drives the truck . auto divider ( has the wedges inside) takes hold when the rear rear spins . have seen the cog slider in the auto dividers split ;; 1 -you don't have an auto divider;;;2- noise would definately be heard. Quote Link to comment Share on other sites More sharing options...
doubleclutchinweasel Posted March 7, 2022 Share Posted March 7, 2022 Told ya' they would chime in! LOL! Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment Share on other sites More sharing options...
mechohaulic Posted March 7, 2022 Share Posted March 7, 2022 take a clean pail ; pull gear oil sample from front rear. 1 hour ago, raybing said: The rear set drives and both axles shafts are repaired. But only rear set moves truck both axle shafts ?? both from rear rear or all 4 from both rear ends. no big pieces in banjo i would check the front rear axles. as earlier stated jack up one side at a time on front = spin the wheels. have seen axles break clean like machine shop did it. broken axle shows up, you know the "broom handle technic' for axle removal ? saves dropping the broken pieces in housing hopefully eliminating pulling chuck. 1 Quote Link to comment Share on other sites More sharing options...
raybing Posted March 7, 2022 Author Share Posted March 7, 2022 I just removed short side axle drive cap. It moves gear set in side Quote Link to comment Share on other sites More sharing options...
raybing Posted March 7, 2022 Author Share Posted March 7, 2022 Taking off 4 bolts cover now Quote Link to comment Share on other sites More sharing options...
mechohaulic Posted March 7, 2022 Share Posted March 7, 2022 hate to leave mid-steam just got phone call ; retired i'm still doing road calls. hopefully back in couple hrs. didn't want you to think i just left. Quote Link to comment Share on other sites More sharing options...
raybing Posted March 7, 2022 Author Share Posted March 7, 2022 No issues under 4 bolt cover Quote Link to comment Share on other sites More sharing options...
raybing Posted March 7, 2022 Author Share Posted March 7, 2022 Ok thanks Quote Link to comment Share on other sites More sharing options...
raybing Posted March 7, 2022 Author Share Posted March 7, 2022 Quote Link to comment Share on other sites More sharing options...
raybing Posted March 7, 2022 Author Share Posted March 7, 2022 I had it all wrong. Rear driver all the time. Front engaged with air switch. Duh. No broken pcs in front axle. Quote Link to comment Share on other sites More sharing options...
mechohaulic Posted March 7, 2022 Share Posted March 7, 2022 i'm back!! longer road call then should have been . wrong cover. the four bolt cover was for the interaxle divider lock out on the front end. Quote Link to comment Share on other sites More sharing options...
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