Scott74 Posted July 18, 2023 Share Posted July 18, 2023 Hey everyone! Needing some help. I have a 74' RL700L with the ENDT 676 Baker in it and the maxitorque 12 speed. I was hauling the other day and lost 3rd Direct gear. Will go into gear once RPM's drop but as soon as you go to accelerate it just spins. I drained oil and found a chunk of metal in drain plug. I was hoping to put some heavier oil (85-140) in it. I had 80-90 in it and temps got up to 200 degrees pulling about 2k feet in elevation. Does anyone know if I can bolt an 18 speed behind this motor or am I pretty much stuck with the 12 speed? Thanks in advance! Quote Link to comment https://www.bigmacktrucks.com/topic/73062-transmission-help/ Share on other sites More sharing options...
mrsmackpaul Posted July 19, 2023 Share Posted July 19, 2023 Just drop the box out, stand it on its bell housing and lift it apart, PAI stock all the parts as far as I know They are pretty simple to work on Use the proper gaskets and silicon, sicka flex or form a gasket and you'll be right Must of been a pretty hard change that broke the gear or dog, these boxes are regarded as pretty indestructible Amyway as to the 18 speed, it will fit but Im thinking a fair few changes are needed Paul 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73062-transmission-help/#findComment-535162 Share on other sites More sharing options...
fjh Posted July 19, 2023 Share Posted July 19, 2023 2 hours ago, mrsmackpaul said: Just drop the box out, stand it on its bell housing and lift it apart, PAI stock all the parts as far as I know They are pretty simple to work on Use the proper gaskets and silicon, sicka flex or form a gasket and you'll be right Must of been a pretty hard change that broke the gear or dog, these boxes are regarded as pretty indestructible Amyway as to the 18 speed, it will fit but Im thinking a fair few changes are needed Paul Agree with Paul ! If you have the access to an 18 speed fuller( out of a Mack) then that would be an alternative ! That said you will loose all your back up speeds fuller has 2 your 12 speed has 5 ! The problem may involve a broken shift fork or shift rail ! the model of your unit makes for a difficult remove narrow frame ! You could pull the floor plate remove the center shift lid and look at the rails and forks how ever it sounds like the trans has to come out! Can you post a picture of the piece you have found on the drain plug! the only dog clutches in this are on the splitter and you still have hi /low Correct? 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73062-transmission-help/#findComment-535176 Share on other sites More sharing options...
Geoff Weeks Posted July 19, 2023 Share Posted July 19, 2023 If you like what you have, it is ALWAYS cheaper and easier to fix what you have than it is to replace with something else. Driveshaft will be different length almost 100% sure, then there is the mounts and shift. If you have a donor truck that is the same, that you can swap parts off of, it isn't bad, but it is the little stuff that causes the most pain, doing swaps. Quote Link to comment https://www.bigmacktrucks.com/topic/73062-transmission-help/#findComment-535180 Share on other sites More sharing options...
JoeH Posted July 20, 2023 Share Posted July 20, 2023 The extra gears of an 18 are a waste on that motor anyway. Those ENDT676 maxidynes make 90%+ peak torque from about 1000-1200 all the way to 2100 rpms. Unless you're doing a lot of highway speeds all you really need is the 2 stick 5 speed they typically started life with. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73062-transmission-help/#findComment-535234 Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.