Transmission Fluid Leaking problems of the 2005 GMC Sierra 2500

Gm states that dexron-vi is fully backwards compatible with all dexron-iii applications. My vehicle is a 2005 GMC sierra k2500hd, with an 8. 1l gasoline engine and allison 1000 transmission. After performing a routine service on my transmission (fluid drain and refill), replacing the dexron-iii with dexron-vi, I noticed the seals and gaskets leaking from around the transmission. Upon further research, I found that the synthetic dexron-vi is not compatible with certain seals installed in allison brand transmissions. Allison transmission does not approve the use of dexron-vi in its transmissions due to the seal incompatibility (allison service tip #1099p). Another allison document (sa5429en) lists two serial number cutoffs, prior to which contain seals incompatible with dexron-vi. The situation has yet to be resolved - gm denies any possible incompatibility, and will not warrant any damages, while allison representatives have told me that the problem is a direct result of dexron-vi. The estimated cost to replace all of the seals in the transmission is $1,900. 00.