FlurryMac Posted August 17, 2006 Share Posted August 17, 2006 This is my first time on the forum. We're trying to figure this out. I have a 1956 B61T Mack with a duplex transmission. I have installed a 676 engine out of an R Model. I use it to haul grain.The clutch slips even after having installed a button clutch. It only slips the clutch in the higher gears (with or without grain trailer attached). Recommended adjustments have been made to the clutch. It has a new pressure plate and heavy duty double springs in the pressure plate.Does anyone have any suggestion for a remedy to this problem? Has anyone installed a double disc clutch in a B61T using a duplex transmission? Quote Link to comment https://www.bigmacktrucks.com/topic/1416-double-disc-clutch/ Share on other sites More sharing options...
rewdoxiepup Posted August 17, 2006 Share Posted August 17, 2006 Hello, You might wanna check the flywheel for proper thickness, It sounds like a problem I once had with a Cat/Fuller set up in a Pete 379, The truck owner had the flywheel cut at a NAPA machine shop and they cut it too thin making clutch adjustment impossible. We wound up buying a new flywheel from Cat. Just something to check!. Good Luck. E.S.D. Quote Link to comment https://www.bigmacktrucks.com/topic/1416-double-disc-clutch/#findComment-7086 Share on other sites More sharing options...
Rob Posted August 17, 2006 Share Posted August 17, 2006 Hello, You might wanna check the flywheel for proper thickness, It sounds like a problem I once had with a Cat/Fuller set up in a Pete 379, The truck owner had the flywheel cut at a NAPA machine shop and they cut it too thin making clutch adjustment impossible. We wound up buying a new flywheel from Cat. Just something to check!. Good Luck. E.S.D. Did the machine shop only grind the friction surface and not the mounting surface a corresponding amount? They have to be ground together or the clutch disc(s) will not have full contact pressure between the pressure plate, and intermediate disc, and flywheel causing slip you will not be able to adjust out. What style clutch do you have installed?Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/1416-double-disc-clutch/#findComment-7087 Share on other sites More sharing options...
scott Posted August 19, 2006 Share Posted August 19, 2006 i put a two disc clutch in with an e-6 350 and a q-box. the part search was a killer,longer input shaft, deeper clutch housing, two disc flywheel, and the right linkage were tough to come by. longer input for a duplex???.if you find one don't forget to count the gear teeth. the trans mounts have to be redrilled 1 1/2 '' rearward, which will means drive shaft work. i did all my work with the cab off so it wasn't too bad. nostalgia and the thought that the q-box would keep the swap simpler didn't pan out. if i were doing it today i'd look into the big 8speed-low low fuller and convert to a pull clutch. if you decide to go with a later tranny don't forget about your rear end ratio. back to the duplex, a lot of early R-models had them so that could help widen your search. a friend used a 7 speed mack trans behind a 300 maxidyne in an early DM that originaly had a 673 and a quad-box to get him to highway speed. hope this helps. good luck. scott Quote Link to comment https://www.bigmacktrucks.com/topic/1416-double-disc-clutch/#findComment-7125 Share on other sites More sharing options...
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