Recently had the transmission in my 2001 Blazer 4x4 repaired at a reputable nation-wide trans shop for a stripped sun shell. I just couldn't see flat-backing a rebuilt tranny in my garage in the cold on a 4x4 right now. Too many other things going on that are demanding my attention.

Original trans was rebuilt. Torque converter was replaced with an unspecified rebuilt converter to eliminate metal particles. GM TSB says this is not necessary but trans shop insisted in order to give warranty.

I have the vehicle back after $2300 repairs and I despise the way the TCC now works. 600 RPM drop from 2000 rpm down to 1400rpm all at once at 46 mph in 4th gear. Not smooth at all. I can brake stall this torque converter to over 2300 RPM. Tap the brake with it engaged at 46mph and RPMs go up 600 RPM. Before recent repairs the TCC would only vary 200 rpm during operation at 46 mph and was obviously a lot lower stall converter. Almost all of my driving to work is between 40-50mph, so I am very aware how the TCC connects and disconnects and when it happens. I had a bluetooth OBD2 tool plugged into the OBD2 port when I took the vehicle in, and it was removed during repairs.

Code on the original converter was DCNF (I replaced it once before when I had the engine out because I was concerned about a thrust bearing failure I had, and the replacement converter at that time operated exactly the same as the old one. As near as I can figure out the torque converter should be a 1600-1800 RPM converter that uses both PWM and ECCC and has woven carbon friction material. I believe it is the only converter listed for the 1998-2002 Blazers.

Based on my observations I am concerned that the wrong converter is in the vehicle, and that PCM programming has been done to make it work. Can anyone tell me if tranny shops commonly do PCM programming to make generic converters work in a vehicle it is not designed for?

The high stall speed, large variation of RPM when applying, and the severity of TCC application does not seem right to me. Furthermore, I feel I will be losing significant gas mileage with the significantly looser converter during the 50% of my driving time when the TCC is not applied.

Comments please. Thanks in advance.

Les