Medium and Heavy Trucks
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Hi my name is***** will be glad to help. Are you getting any fault codes? Click this link for the procedure to retrieve the fault codes and the second link for the troubleshooting info for the fault. Let me know what you have for codes and if you need more help.
Thanks for the info. there are known issues with the XY shifters on these transmissions and sometimes may not throw a code. It is possible the XY shifter ans solenoids are not fully engaging the sliding collars into the speed gears on the main shaft on the transmission if it is worn. Over time this can also wear the shift collars and speed gear teeth bullet shaped causing a jump out condition as well. Click this link to view the XY shifter.
Service the transmission oil and inspect the oil and transmission filter for metal and discoloration indicating excessive internal wear or any chunks/debris in the oil or bottom of the case with a magnet. If the drain oil has streaks of what looks like grey/silver neverseize then it is from filings from internal problems and wear. You will have to remove the mat and the section of floor above the transmission. Most trucks will have an access panel to access the top of the transmission. Let me know if any of this might have already been checked with the transmission out for the clutch. The top cover should have been removed and the clutching collars and main shaft gears inspected for excessive wear. I hope this helps
Thanks for the update. Here is what I would do. Since the xy shifter is good and be sure the harness and connector pins are good and free from corrosion and damage. If confirmed, have the transmission TCM ( computer reprogrammed with the most current software and then see if the problem still exists. If it does then I would pull the top cover and do a good visual inspection of the shift collars and gears. It sounds like you could have a synchronizer problem inside the transmission if this problem occurs when shifting between the high and low range gears. This would require the back section to be removed from the transmission to repair this and most places will not warranty just a back section replacement as the main box has wear and possible contamination from age and any problems the current transmission has. but inspecting through the top cover to look for bullet shaped shift collars and internal teeth of the mainshaft gears as well as removing the back section to inspect the synchronizer. Unfortunately a visual inspection is needed to confirm but this is what the next step would be aside of a reman exchange if the software does not correct the problem and there are no codes.
Hi Zolta, Did you get this resolved?