I experienced this in all 4 of my Duramax/Allison Trucks. In June I purchased the newest one, an 03 and immediately towed my 26 foot 11,000 lb show car carrier to <st1

lace><st1:City>Tulsa</st1:City>, <st1:State>OK</st1:State></st1

lace> from <st1:City><st1

lace>San Diego</st1

lace></st1:City>. In total I drove 3500 miles in 2 weeks most of it on the highway in 5<SUP>th</SUP> gear. I drove around SoCal for the next several weeks accruing another 1000 miles or so. At 4,000 miles I was informed that Trans-Go had a new shift kit they were preparing for market and had it immediately installed.
What we found in the tranny was a little disturbing. The second gear clutches at only 4,000 miles were already starting to burn up. This I was told is the major weakness of the Allison 1000. The Trans-Go tranny kit modifies the second gear clutch springs and modifies the line pressure for all gears. The torque converter is sub par for the extra hp and towing that most of us do. So I choose to buy the Vigilante triple plated billet torque converter. The kit also stops the shuttering of the 4-5 shifts under a load by locking the converter up immediately instead of progressively.
I am told the new converter and tranny kit is good up to 900lb/tq. This is more than enough for me.
Technically specking the stock tranny is only good at the factory hp rating of 300. Anything above that and the weak areas like the second gear clutch pack goes south fast. Combine the extra hp of a programmer and a heavy tow load and it will go that much quicker.
The reason for this was shift quality. GM wanted a Cadillac shift in a HD truck. The tranny is good for 100,000 if Mom and Pop Jones use it to get groceries but not if you release the extra power from the DMax or tow with it.
The truck now shifts better than any of my Dmax/Allison trucks ever did before. I took a couple of picture of the box because I was late for the whole installation. For the complete price of the installation and parts I will refer you to Marvin. He is one of the master minds behind the kit.
Marvin
The Trans Shop
<st1

lace><st1:City>El Monte</st1:City>, <st1:State>CA</st1:State></st1

lace>
626-442-5817
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