Hmm sounds very interesting, and that it happens only in 2nd gear. Well the first thing I would do is drop the valve body and check the flex band, it's possible that the band will need to be adjusted and sometimes when they are way out of adjustment the band strut will fall so try adjusting the band, this may help with a slipping 2nd gear, the thing is that it could still slip due to a loss of pressure in the servo due to a leak. The band when applied has aprox 2300-2800 PSI of clamping force so yea... Oh and for those never adjusted a band, the front band adjuster is located on the driver side of the bell housing behind the linkage. You just have to loosen the locknut then tighten the adjuster to 72 inch lbs, back off 3 turns then tighten the locknut to 25-30 ft-lbs. The rear band is the same except you back off 2 turns. The rear band rarely needs adjusting because that band is applied only in reverse and manual 1st. And don't be concerned if you experience a slow WOT 1-2 shift, it's uhh normal and it sucks.
The last thing on my mind is something with the torque converter but like I said last thing on my mind. I would bet money on the band adjustment, if it slips excessively it could cause some engine buckling, the band holds the driving shell stationary thus holding the sun gear stationary and if it slips a little it will slightly lockup the transmission making it a little hard on the engine to turn. If you want to make it almost slip free you would want to upgrade the band lever, the stock lever is either a 2.5 or 2.9, some are 3.X, generally the higher 3's to low 4's are fine, anything higher would be very brutal on the transmission. But you would have to remove the transmission to gain access to the lever shaft plug to be able to remove the lever so is it worth it...
But first try out adjusting the band, I cannot say 100% that will correct the problem but if you tow often and haven't adjusted that band in a while then it's most likely the culprit, even if you don't tow often, if you haven't adjusted that band in long time or never then you can bet the farm on that part.
Tell me how everything goes or doesn't go, if still no good then I can go forward from there. Don't be alarmed if I don't respond for maybe a day or two, I am without internet and have been busy. I have a transmission I'm overhauling so I will be busy for a day or two.
Last edited by ramvan2500; 08-02-2012 at 09:57 AM.