TSB – Flash: Torque Converter Shudder Or 1-2, 2-3 or 3-4 Upshift Bumps

NUMBER: 21-001-08 REV. B
GROUP: Transmission
DATE: February 15, 2008

Flash: Torque Converter Shudder Or 1-2, 2-3 or 3-4 Upshift Bumps

This bulletin involves reprogramming the Powertrain Control Module (PCM) with new software and replacing the torque converter as required.

2007 (JK) Wrangler

NOTE: This bulletin applies to JK models built with a 42RLE automatic transmission (Sales Codes DFF, DGV, or DG2).

The vehicle operator may experience one or more of the following symptoms:
1. Transmission Shudder – (42RLE)
a. This condition can only occur after the vehicle has been driven and the torque convertor is past the break in period. Torque Converter break in can be confirmed with the StarSCAN®.
b. If experienced, the shudder may occur when the transmission temperature is between 38° C and 54° C (100° F and 130° F) during steady state driving with the torque convertor in partial lock (EMCC) operation. The shudder feels like the vehicle is being driven over rumble strips.
2. 1-2, 2-3 or 3-4 Upshift bumps

TSB 21-001-08 REV. B


  1. I have a slight shudder on a 2008 on the 2 to 3 shift. Was wondering if this tsb applies to 2008’s. It states 2007 models?


  2. I have a 2008 JK with just over 3k on it. It shuttered between 2nd & 3rd and then lost 3rd all together. Took to local dealer this morning for repair. Dealership of course had no clue of any transmission problems with the 07-08 JK’s.

  3. I’ve had my 3/2007 Wrangler Unlimited to the local dealer 4 times with a shudder between 1st and 2nd gear on cold starts and every time the mechanic doesn’t experience the problem. I finally took the service adviser for a ride and he stated that unfortunately it wasn’t a Toyota and Chrysler has had problems with this automatic trans for years even when it was a front wheel drive trans and I’d just have to deal with it. I find it hard to believe Jeep doesn’t have a fix for this shudder. The service writer stated the problem is documented if I run into problems later with the transmission but for peace of mind I would like the problem to be resolved. Is anyone else experiencing this problem?

  4. Update on JK trans problem. Dealer found bad speed sensor and replaced it. Now I have have 3rd gear again, but still shutters every once in awhile between 2nd & 3rd. And of corse dealer can’t duplicate shutter when at shop. Will keep you posted.

  5. I have had the transmission rebuilt 5 times now by the dealerships (yes, that’s plural), two new torque converters and a reprogrammed computer. Just got my 08 Jk back from the dealership and it miss shifted again. The dealer took three hundred miles last time to duplicate the problem (2 service writers and a tech took the vehicle home). I have submitted for lemon law. Starter, shifter, and door latches have also broken or been replaced. My Gig radio replaced 3 times.

  6. I feel the shudder in 2nd at very low speed. when it shifts to 3rd it stops imediatly. My dealership looked it up and found nothing but the shift improvement flash. It goes in next week for that procedure. could this be the problem?

  7. My 2007 JK Wrangler Unlimited 4 dr with auto transmission is exhibiting shuddering/thumping noise around 35 – 40 mph. My wife even recognized issue while driving vehicle. Sound and feels like jeep is falling apart.
    Looked up JK issues and found service bulletin for software upgrade and possible torque converter change. Went to dealer to discuss and they never heard of problem. Anyone suggest where best place to go to have problem fixed?

  8. -2008
    -jk wrangler
    -about 77,000 miles
    -when taking off 1st to second it makes a rubbing /squeaky noise when shifting

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