Heli0z Posted January 10, 2018 Share Posted January 10, 2018 Recently purchased my first mack! It's a 2001 RD688s with a 4 speed Allison ht740 automatic unfortunately I have the small problem of inheriting a fatal transmission issue with the purchase. I was also able to score a reman and got down to wrenching today. I have the tools and experience to do the job but am confused about how to get the flexplate drive bolts off. Does not seem to be "standard" I peeked through the access cover and all I can see is the torque converter bolts and the starter ring gear no way to access the bolts that attach the flex plate to the starter ring gear! Please help! What am I missing? Quote Link to comment https://www.bigmacktrucks.com/topic/52176-e7-ht740-how/ Share on other sites More sharing options...
ksrolloff Posted January 10, 2018 Share Posted January 10, 2018 take torque converter bolts out.... pull trans..........flex stays with flywheel Quote Link to comment https://www.bigmacktrucks.com/topic/52176-e7-ht740-how/#findComment-389385 Share on other sites More sharing options...
Heli0z Posted January 10, 2018 Author Share Posted January 10, 2018 This diagram is what has me confused. It says to remove the drive bolts which in this application can't be accessed. So if I remove the 40 bolts around the torque converter and it stays in place on the crankshaft how can I then remove TC if its bolted from the opposite side. Ill try to visit the dealer tonight when I pick up parts and see if I can get them to print a diagram for me I'm one of those visual learners. Quote Link to comment https://www.bigmacktrucks.com/topic/52176-e7-ht740-how/#findComment-389419 Share on other sites More sharing options...
BC Mack Posted January 10, 2018 Share Posted January 10, 2018 as above... remove all the bolts from the flexplate through the aperture on the front of the bellhousing, these hold the flexplate to the torque converter... then remove the periphery bolts on the bellhousing and remove trans.... the flexplate will remain bolted to the crankshaft. on refitting, before you get too many bolts on the bellhousing, start all the ones on the flexplate, they have a habit of being a little "off" if you bolt the trans on and have no wiggle room, maybe that's why it's called a 'flex' plate. I also recommend 'transynd' synthetic, more $$$ than regular atf, runs cooler and less oil changes so it works out about the same per mile as atf.... if your tranny rebuilder guy is local ask his opinion on oil, maybe they will give you his bulk price.... I've seen some run on engine oil so check into it first. http://www.allisontransmission.com/parts-service/approved-fluids if you have a trans cooler then flush it out, the garbage from the failure may end up back in your new trans...!!! if all else fails go visit your local transit depot, they do this work all the time and could help you with advice.. though the 740 isn't in common use anymore. BC Mack Quote Link to comment https://www.bigmacktrucks.com/topic/52176-e7-ht740-how/#findComment-389421 Share on other sites More sharing options...
BC Mack Posted January 10, 2018 Share Posted January 10, 2018 4 minutes ago, Heli0z said: This diagram is what has me confused. It says to remove the drive bolts which in this application can't be accessed. So if I remove the 40 bolts around the torque converter and it stays in place on the crankshaft how can I then remove TC if its bolted from the opposite side. Ill try to visit the dealer tonight when I pick up parts and see if I can get them to print a diagram for me I'm one of those visual learners. yes, remove the 12 drive bolts from the "front" access hole, usually there is a cover plate on the engine side, worse case is you pull the starter.. the 40 bolts are to join the two halves of the TQ, don't go there. BC Mack Quote Link to comment https://www.bigmacktrucks.com/topic/52176-e7-ht740-how/#findComment-389422 Share on other sites More sharing options...
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