Hi, I have searched far and wid and read many of your resopnses to posted questions and I think you are teh man to ask. I have a 97 Bluebird All american that is destined for a conversion project. It has a 8.3L C series Cummins and a 1000 series world tranny with a 6 stage retarder. It runs and sifts like a champ until I start downhill and use the retarder.
Today, I started down Monarch Pass in Colorado (30 miles east of Gunnison where I live, this was a test run). I started the decent in 3rd and engaged the retarder manually in stage 1 at 35 to 37 MPH. It seemed that after a few corners when applying the retarder (I assume the tranny temp had risen some, but there was not an indication as such on the tranny temp gauge), and slowing to a speed near 30 MPH, the tranny tired to downshift into 2nd, then immediatedly shifted back into 3rd. It dod this a few times and then locked in 4th (I assume some "limp" mode), illuminated the "do not shift" light and would not shift. The retarder still worked. I stopped, turned the bus off, restarted it and the tranny worked correctly. I put it in 2nd and eased it down teh pass only using teh retarder in "0" mode. It did the downshift thing once more, but not again and came down without further incident, although the grade had diminished by then.
So, what have I got going. With the retarder activated, is the tranny trying to downshift once I slow to some pre-determined ground speed, similar to the Allisons in the Duramax? If so, is it not able to hold the downshifted gear due to some pressure related issue? (weak spring? leaky seal? gremlins?)
Any and all help is greatly appreciated. I do have a friend that has an Allison scanner if searching for stored codes will help.
Thanks for all the great advice here, Doug
Today, I started down Monarch Pass in Colorado (30 miles east of Gunnison where I live, this was a test run). I started the decent in 3rd and engaged the retarder manually in stage 1 at 35 to 37 MPH. It seemed that after a few corners when applying the retarder (I assume the tranny temp had risen some, but there was not an indication as such on the tranny temp gauge), and slowing to a speed near 30 MPH, the tranny tired to downshift into 2nd, then immediatedly shifted back into 3rd. It dod this a few times and then locked in 4th (I assume some "limp" mode), illuminated the "do not shift" light and would not shift. The retarder still worked. I stopped, turned the bus off, restarted it and the tranny worked correctly. I put it in 2nd and eased it down teh pass only using teh retarder in "0" mode. It did the downshift thing once more, but not again and came down without further incident, although the grade had diminished by then.
So, what have I got going. With the retarder activated, is the tranny trying to downshift once I slow to some pre-determined ground speed, similar to the Allisons in the Duramax? If so, is it not able to hold the downshifted gear due to some pressure related issue? (weak spring? leaky seal? gremlins?)
Any and all help is greatly appreciated. I do have a friend that has an Allison scanner if searching for stored codes will help.
Thanks for all the great advice here, Doug