Ausmack1 Posted April 11, 2023 Share Posted April 11, 2023 Hello i have a Mack Trident 2013 model mp8 535hp with the m drive auto transmission. The truck makes a loud squeak noise when it changes to the high range in the box from 6 to 7th or 8th and somtimes when it dose the noise it will clunck into the gear. What could this be and should i be worried? as it still drives and no codes come up. Thanks in advance Quote Link to comment Share on other sites More sharing options...
fjh Posted April 11, 2023 Share Posted April 11, 2023 There is a stop plate in the lid that can fail also the synchro in these is sometimes problematic! the clutch valve is likely what you hear squeaking! Question is your trans set up with 2 speed reverse! ? Just sayin! Quote Link to comment Share on other sites More sharing options...
Ausmack1 Posted April 12, 2023 Author Share Posted April 12, 2023 On 4/12/2023 at 12:42 AM, fjh said: There is a stop plate in the lid that can fail also the synchro in these is sometimes problematic! the clutch valve is likely what you hear squeaking! Question is your trans set up with 2 speed reverse! ? Just sayin! Hello thank you for the reply yes it has 2 speeds in reverse. The squeak nosie dosnt happen between other gear just 6-to7 or 6to8 ( only when it gose from low range to high) . If it was the clutch valve wouldnt it do it every gear change? Quote Link to comment Share on other sites More sharing options...
fjh Posted April 13, 2023 Share Posted April 13, 2023 True ! Usually the sycro is the main issue! If you have the two speed reverse don’t select hi while moving! Or have it programed out! It can create issues for the synchro ! By design the thing is very flimsy Shifting on the fly in reverse can cause the syncro cone to work loose from its hub! resulting in pre mature failure (Just An observation) ! You likly have a synchro issue there! The broken stop plate will show up as a code sooner or later if that is an issue you likely have a synchro issue! The trans will have to come out! Bunch of special tools to work on this trans! Have them check your clutch wear before the transmission is pulled you may just as well do the clutch if it is more than 50 percent worn !also in this country the trans had a 3 year 750000 Warranty ! how ever you are well beyond that category ! Note I'm no guru on these how ever seen a fair few of these fail under warranty and just out of warranty ! for the most part the trans has been pretty dependable as much as I hate to admit it! MACPRO ? Advice Please! Just sayin! Quote Link to comment Share on other sites More sharing options...
Mackpro Posted April 13, 2023 Share Posted April 13, 2023 As FJH said range shift/synchro issues. There is a bulletin on removing the PTO /PTO cover and checking the range cone for excessive play. They make a repair kit but usually we get the Reman rear range housing that comes with everything together. I did a couple many years ago it wasn’t to bad with the correct tools. I think it can be done in the truck ( CH/CX style truck with floorboard access) . In a Volvo the trans has to be pulled because the top cover has to come off. Quote Link to comment Share on other sites More sharing options...
fjh Posted April 13, 2023 Share Posted April 13, 2023 2 minutes ago, Mackpro said: As FJH said range shift/synchro issues. There is a bulletin on removing the PTO /PTO cover and checking the range cone for excessive play. They make a repair kit but usually we get the Reman rear range housing that comes with everything together. I did a couple many years ago it wasn’t to bad with the correct tools. I think it can be done in the truck ( CH/CX style truck with floorboard access) . In a Volvo the trans has to be pulled because the top cover has to come off. Thanx pro ! We never tried this in the truck however we often wanted to try it! Quote Link to comment Share on other sites More sharing options...
Ausmack1 Posted April 13, 2023 Author Share Posted April 13, 2023 7 hours ago, Mackpro said: As FJH said range shift/synchro issues. There is a bulletin on removing the PTO /PTO cover and checking the range cone for excessive play. They make a repair kit but usually we get the Reman rear range housing that comes with everything together. I did a couple many years ago it wasn’t to bad with the correct tools. I think it can be done in the truck ( CH/CX style truck with floorboard access) . In a Volvo the trans has to be pulled because the top cover has to come off. Thank you for your reply im. New to using this sight how to i go about finding the bulletin for the pto removal? Quote Link to comment Share on other sites More sharing options...
fjh Posted April 13, 2023 Share Posted April 13, 2023 1 hour ago, Ausmack1 said: Thank you for your reply im. New to using this sight how to i go about finding the bulletin for the pto removal? Pro may check back he’s good at finding stuff for guys! Best have this looked into at a dealer!they will have all the tools to repair this! 1 Quote Link to comment Share on other sites More sharing options...
Mackpro Posted April 13, 2023 Share Posted April 13, 2023 1 hour ago, Ausmack1 said: Thank you for your reply im. New to using this sight how to i go about finding the bulletin for the pto removal? It didn’t go into much detail abs was not released to the public. Ill see if I can find a copy Quote Link to comment Share on other sites More sharing options...
fjh Posted April 14, 2023 Share Posted April 14, 2023 4 hours ago, Mackpro said: It didn’t go into much detail abs was not released to the public. Ill see if I can find a copy Of Coarse not! 🤐Wouldn't want to admit to an issue would we!🤐 😡 Thanx bro! hopefully you can dig up the info! It don't really matter its a dealer repair for the most part! Still need the PTT to park the trany to remove the lid! Me thinks!😡 Quote Link to comment Share on other sites More sharing options...
Mackpro Posted April 14, 2023 Share Posted April 14, 2023 You can get the shift control housing off without Tech Tool but it’s tricky. You have to shoot air with a rubber tipped blow gun in a certain sequence into the air passages in the control housing . I had better luck that way than using TechTool. Here’s how. https://static.nhtsa.gov/odi/tsbs/2014/SB-10055631-2447.pdf Quote Link to comment Share on other sites More sharing options...
Mackpro Posted April 14, 2023 Share Posted April 14, 2023 The bulletin on the 6th to 7th grinding noise. Quote Link to comment Share on other sites More sharing options...
Mackpro Posted April 14, 2023 Share Posted April 14, 2023 That bulletin sends you to SNM 15-002b on repairing. I can’t seem to locate yet . Quote Link to comment Share on other sites More sharing options...
Mackpro Posted April 14, 2023 Share Posted April 14, 2023 Here is the repair options https://static.nhtsa.gov/odi/tsbs/2021/MC-10189847-0001.pdf Quote Link to comment Share on other sites More sharing options...
fjh Posted April 14, 2023 Share Posted April 14, 2023 9 hours ago, Mackpro said: You can get the shift control housing off without Tech Tool but it’s tricky. You have to shoot air with a rubber tipped blow gun in a certain sequence into the air passages in the control housing . I had better luck that way than using TechTool. Here’s how. https://static.nhtsa.gov/odi/tsbs/2014/SB-10055631-2447.pdf Thanks Pro! I had very little to do with these ! Had a side walk superintendent over veiw of the jobs and very little hands on ! When these work they work decent But when they don't work they are expensive! 1 Quote Link to comment Share on other sites More sharing options...
Ausmack1 Posted April 15, 2023 Author Share Posted April 15, 2023 On 4/14/2023 at 12:53 PM, Mackpro said: The bulletin on the 6th to 7th grinding noise. Thank you Pro for the information. Do you happen to have the specifications for the range cone how much play it can have or a manual? Also dont know if this changes anything when truck is cold in the morning it changes to high range with out noises for about 10min Quote Link to comment Share on other sites More sharing options...
fjh Posted April 16, 2023 Share Posted April 16, 2023 17 hours ago, Ausmack1 said: Thank you Pro for the information. Do you happen to have the specifications for the range cone how much play it can have or a manual? Also dont know if this changes anything when truck is cold in the morning it changes to high range with out noises for about 10min Temperature change I would think! The cone is likly a bit loose on the hub!refrain from changing speeds on the fly in reverse! It will only make matters worse! If this is what is going on! Just sayin! The hub and cone are a real fragile design ! Quote Link to comment Share on other sites More sharing options...
Mackpro Posted April 19, 2023 Share Posted April 19, 2023 On 4/15/2023 at 6:36 PM, Ausmack1 said: Thank you Pro for the information. Do you happen to have the specifications for the range cone how much play it can have or a manual? Also dont know if this changes anything when truck is cold in the morning it changes to high range with out noises for about 10min I’ll see if there is anymore info on this but the bulletin did not go into detail. Quote Link to comment Share on other sites More sharing options...
Mackpro Posted April 19, 2023 Share Posted April 19, 2023 https://static.nhtsa.gov/odi/tsbs/2015/SB-10082931-0699.pdf Only info is more repair info Quote Link to comment Share on other sites More sharing options...
Ausmack1 Posted April 20, 2023 Author Share Posted April 20, 2023 14 hours ago, Mackpro said: https://static.nhtsa.gov/odi/tsbs/2015/SB-10082931-0699.pdf Only info is more repair info Thank you for the information Pro. When the range synchro fails dose that usally mean full box needs to be rebuilt or can you get away just doing the range box? Quote Link to comment Share on other sites More sharing options...
Mackpro Posted April 20, 2023 Share Posted April 20, 2023 You can get just a synchro kit or the complete back housing pre-assembled with synchro installed. The hub bolts to the main box best I remember and it’s the only thing on the main box( main housing) that you have to change on the main box. It’s been several years since I’ve done one however. I did once have the hub break loose from its mounting bolt tabs and cause quite a mess. Shockingly they were still driving it. Quote Link to comment Share on other sites More sharing options...
Mackpro Posted April 20, 2023 Share Posted April 20, 2023 When I went to the M-drive/I-shift school. I was shocked when I got to pull the top cover (shift control housing) off. Wasn’t really much inside there Quote Link to comment Share on other sites More sharing options...
Mackpro Posted April 20, 2023 Share Posted April 20, 2023 Here’s the rear synchro housing kit with hub . Quote Link to comment Share on other sites More sharing options...
fjh Posted April 20, 2023 Share Posted April 20, 2023 2 hours ago, Ausmack1 said: Thank you for the information Pro. When the range synchro fails dose that usally mean full box needs to be rebuilt or can you get away just doing the range box? Not usually ! The back section kit is the way to go as shown there! We saw a fair few failures specially with 2 speed reverse enabled ! There inlies my recommendation to dis able or not use on the fly! I have seen that syncro cone ripped to shreads on one occasion! It is amazing thou how stronge the trans is when you see the inside as Pro mentioned! aside from that syncro! not that many mechanical issues otherwise just the electrics ! 1 Quote Link to comment Share on other sites More sharing options...
Ausmack1 Posted April 21, 2023 Author Share Posted April 21, 2023 On 4/20/2023 at 10:34 PM, Mackpro said: Here’s the rear synchro housing kit with hub . Seems like in Australia u cant get this kit. I can get the range synchro kit which includes whats in the photo would i need change anything else while im in there Quote Link to comment Share on other sites More sharing options...
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