Allison trans Exhaust brake problem

[Bilstar211]

Looking for some help... I have a 1998 HR Imperial w/8.3 cummins and 6 sp Allison trans(Model MD3060) w/Jacobs exhaust brake, towing a 26' car hauler. Two weeks ago I was driving down 8% grade in the Smokey Mountains w/exhaust brake on. The trans temp went to 260+ (normal is 195-200). After a few minutes the exhaust brake quit working and the trans stuck in 4th gear. Finally got down mountain, to a Walmart. Turned off ignition switch and then back on. Trans seemed to clear. Put in gear and drove for a minute and trans sticks in 3rd gear. Not able to manually shift into any gear or neutral. Went back to parking lot. Disconnected all power to coach/engine to reset the Trans ECM. Tried again, all systems seemed to be normal. Started out again, started down mountain and exhaust brake quit working, but was able to manually shift to all gears, (trans temp @ 250). Next day, out of mountains, reset trans ECM again. For the next 200 miles everything worked normal.(trans temp normal , 195-200) Used exhaust brake extensively and all trans functions worked properly. I just received a code of " 1d 1462"�. If anyone has had similar issues, I would appreciate any info...thanks in advance, Bill

[Bilstar211]

Looking for some help... I have a 1998 HR Imperial w/8.3 cummins and 6 sp Allison trans(Model MD3060) w/Jacobs exhaust brake, towing a 26' car hauler. Two weeks ago I was driving down 8% grade in the Smokey Mountains w/exhaust brake on. The trans temp went to 260+ (normal is 195-200). After a few minutes the exhaust brake quit working and the trans stuck in 4th gear. Finally got down mountain, to a Walmart. Turned off ignition switch and then back on. Trans seemed to clear. Put in gear and drove for a minute and trans sticks in 3rd gear. Not able to manually shift into any gear or neutral. Went back to parking lot. Disconnected all power to coach/engine to reset the Trans ECM. Tried again, all systems seemed to be normal. Started out again, started down mountain and exhaust brake quit working, but was able to manually shift to all gears, (trans temp @ 250). Next day, out of mountains, reset trans ECM again. For the next 200 miles everything worked normal.(trans temp normal , 195-200) Used exhaust brake extensively and all trans functions worked properly. I just received a code of " 1d 1462"�. If anyone has had similar issues, I would appreciate any info...thanks in advance, Bill

[Bilstar211]

Correction on code: it is "d1 4621" ..thanks,

[samert111]

Bilstar211,
I don't see either of these codes in my Allison trouble shooting manual for the MD3060.

Are you sure about the code?