I had a 1983 GMC Suburban 2500 w/7.4L, Turbo 400 and never any transmission problems. I have 2001 Chevy 2500 Suburban with 8.1L and 4L80E transmission and have never had any transmission problems the GM Exec. I purchased it from towed horse trailers before I bought it and owning it for 11 years still have never had any transmission problems. I suspect you will have problems finding a big block in a Chevy or GMC with manual transmission, as the the majority purchase with auto, and some models have the Allison transmission, if I recall.
I personally would not own a manual transmission in a tow vehicle.
