papaindigo wrote:
The F-37 recall (a.k.a TSB 18-023-06) came out in December 06 and applied to all 05/06 CRDs although it is possible some late year 06s came from the factory with the detune done. It included inspection and if necessary replacement of the torque converter, reprogramming of the ECU to reduce HP/torque, and reprogramming of the TCM to raise the shift point rpms. The dealer was "supposed" to put a sticker, likely on the radiator upper cross member, when the recall was done but they did not always do so although if you go to the Jeep web site for owners with your VIN you should be able to see if the recall was done. FYI in some cases, mine was one, the reprogramming of the TCM was NOT done. How to tell:
1. assuming you do not have a GDE TCM tune, email GDE with VIN to check;
2. a pre-F37 TCM will shift into final lockup at ca. 58 mph on a flat road light acceleration and hold that lockup down to a bit above 50mph
3. a post- F37 TCM the final lockup is ca. 62 mph and will hold it down to maybe 55mph.
Good attempt but not quite correct in the details. This was actually addressed with two recalls:
F31 AUG 06 - Changes the shift points. Some vehicles came from the factory with the new shift points already installed e.g. my Jeep was manufactured in Apr 06 and had them from the factory. The behaviour of the new shift points is as you describe above for F37.
F37 DEC 06 - De-tunes the engine. This recall also upgraded the TC for those early models that required it. An upgraded TC already came stock early in the 2006 MY onward. No vehicles came from the factory with F37 already installed though I'm sure there may have been some on the dealers lots that were downgraded before delivery.
Since the two recalls are so close together I'm sure there are plenty of vehicles that skipped F31 and went straight on to F37 which would also include the new shift points but because this was done as two separate recalls there will also be vehicles out there that were manufactured with the upgraded TC and had the new shift points installed at the factory or through F31 but never went on to be de-tuned by F37.
Now, the interesting thing about F31 is that it broke the OBDII interface. This was fixed by F37 so if your vehicle has the new shift points and your OBDII port works you must also have F37.