seans
Member
Many years ago, I performed the DARF mod with an official kit from Dr. A. I did not have many miles on the van and really didn't know what RSN was. I *rarely* did have a shudder in certain conditions. I did the mod even though I really did not need to.
(Although... I do wonder if the shudder is transmitted back through the engine to the harmonic damper. I run the best diesel I can find and after about 195K miles I have had no serious engine issues.)
One thing I did not really like was that I may have gone too big with the drill size. The shifting was a bit loose. I told myself that someday I would reverse the mod.
That day was today. I have been chasing a "sensor 3" transmission code for maybe two years after letting the van sit for the better part of a year. The code returns if I don't use the van, and the van stays in whatever gear it happened to be in. Clearing the code with my code reader fixed things long enough.
I *finally* got off my duff and replaced the transmission fluid, which was long overdue. Before that, I used an oscilloscope to check the sensor 3 signal, which looked fine.
While I had the pan off, I removed the plate and used an aluminum-zinc brazing rod and a propane torch to solder the hole shut.
When I put everything back together, I noticed a LOT of RSN. The scanner told me that it started whenever the torque converter locked up, and stopped whenever it released. The only time I did NOT feel it was under hard acceleration, or if I was coasting perfectly, or going so slow that the torque converter was not locked up.
I pulled the pan again and restored the hole, though I tried to make it a tiny bit smaller. Back together, the RSN was completely gone. It also seemed that the smaller hole helped restore some of the snappiness I lost when I first did the mod.
Thanks again to Dr. A for figuring this modification out and letting us know about it!
(Although... I do wonder if the shudder is transmitted back through the engine to the harmonic damper. I run the best diesel I can find and after about 195K miles I have had no serious engine issues.)
One thing I did not really like was that I may have gone too big with the drill size. The shifting was a bit loose. I told myself that someday I would reverse the mod.
That day was today. I have been chasing a "sensor 3" transmission code for maybe two years after letting the van sit for the better part of a year. The code returns if I don't use the van, and the van stays in whatever gear it happened to be in. Clearing the code with my code reader fixed things long enough.
I *finally* got off my duff and replaced the transmission fluid, which was long overdue. Before that, I used an oscilloscope to check the sensor 3 signal, which looked fine.
While I had the pan off, I removed the plate and used an aluminum-zinc brazing rod and a propane torch to solder the hole shut.
When I put everything back together, I noticed a LOT of RSN. The scanner told me that it started whenever the torque converter locked up, and stopped whenever it released. The only time I did NOT feel it was under hard acceleration, or if I was coasting perfectly, or going so slow that the torque converter was not locked up.
I pulled the pan again and restored the hole, though I tried to make it a tiny bit smaller. Back together, the RSN was completely gone. It also seemed that the smaller hole helped restore some of the snappiness I lost when I first did the mod.
Thanks again to Dr. A for figuring this modification out and letting us know about it!
). I used two containers of the stuff -- the 5hp30 takes nine liters of ATF -- and the RSN went away. 
vic