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2002 Sierra Ext Cab SLT Z71 light acceleration 1st to 2nd shift judder

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Hello all,


Long time lurker first time poster. Just wanted to share my recent experience regarding my 2002 Sierra Z71. I purchased the truck around 18 months ago to use as DD. Over some time I noticed during light acceleration, typically from a stop, the shift between 1st and 2nd gear would give an odd judder at times. After some searching I crossed the TSB 02-07-30-030A which discusses a potential electrical feedback issue from the alternator. Between various sites the topic is discussed but not much regarding the results. If anyone is still dealing with this potential issue (I believe only a few select model years) I wanted to post the parts used and where obtained. I had some difficulty tracking available factory parts through various online suppliers.


Indeed after installing the alternator jumper cable, the judder issue has since nearly vanished. There's a very slight hint still remaining, but at least 99% improved in my opinion. With the parts in hand, I installed the jumper wire over my lunch break with little difficulty. The parts were purchased at mouser.com at little cost (just over $2), however they did not have on hand the ring terminal spec'd by the TSB (no big deal, any fitting terminal will suffice). Parts:


829-12059168

12059168

CABLE CAVITY PLUG


829-12186568

12186568

4P FM BLK CONN ASSY


829-15324973

15324973

LOOSE CABLE SEAL


829-12048074

12048074-L

FMALE 150 SERIES TIN


Note if the part number you're looking denotes an "L", this designates a loose part and quantity one (1) can be ordered as many the items require a minimum count order.


Hope this helps anyone looking to attempt the 02-07-30-030A TSB themselves. Search the TSB number to find installation details (I've opted not to post it here to avoid excess post clutter). The new black alternator connector is marked A-B-C-D looking from the top. I used a small paper clip to push along side the pin which eventually worked the pins free of the existing connector. Simply for the newly purchased connector, your existing brown wire fits in "B", existing gray wire in "C" and assembled jumper wire in "D". The purchased red plug fits into "A" as its not used. Make sure the wires are seated in the new connector, be careful the push pin's tangs catch as they may have bent during removal.


P.S. Also note the shifting "judder" could be compounded by whats known as "frame beaming". Another must upgrade is use of GMT900 hydraulic body bushings. The hydraulic mounts help "decouple" the frame and cab thus dissipating the effect (better than 80% reduced cab "jiggle").


Hope this info can and will help somebody, good luck.



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