I have a 2500HD with an 8.1L and S6-650 ZF 6 speed manual transmission that I bought new in 2001. Manual shift transfer cases were hard to find back in 2001 let alone a manual transmission. I got lucky and found one in my home town even in the color of my choice and with bucket seats. We got the wife a new car last summer and I started driving her Tahoe since then so the HD just hangs out in the garage most of the time now. It just turned 50,000 miles and had gone less than 500 miles since July 2006 when we got the G6. No, I don’t want to sell it..
If you find a truck with an 8.1L and ZF 6 speed it will be the last manual transmission truck you will ever own because you will hate it so much you will never want to drive a stick again. Yeah, I friggen hate my ZF badly. Talk about an awkward knotchy transmission…… I wish it would have had a NV5600 instead. Nothing like launching the truck from a stop sign only to find yourself going backwards in reverse because 1st and Reverse are so damn close it is easy to stick it in the wrong gear. It still bewilders me why the hell GM used the ZF behind the Dirtymax and 8.1L in that plateform for those years. Idiots!
The 8.1L is a great engine and gets 10 miles a gallon loaded, unloaded, on the highway or parked in the garage. It needs a quart of oil every 1200 miles like clock work. I am not complaining as low fuel economy and oil consumption are common on bigger bore engines. The 8.1L is not fast…but pulls like a freight train. It is a very economical alternative to a diesel if pulling is your thing. The 6.0L with the NV4500 is a nice combo as well and equally as hard to find but probably be a more practical as a daily driver.
Manual transmissions will be available in the 2008 2500 and 3500 GMT900’s second quarter of this year. The transmission is rumored to be a Tremec this time opposed to New Venture and ZF as GM used in the past. The 8.1L will no longer be offered in the Silverado line up but there the 6.0L is a pretty nice engine as well. There will be a supercharged 6.2L coming to the HD line up within the sometime in 2009. Knowing how GM is they probably won’t offer it with a manual trans with that engine because you know, people would probably want to by that combo or something.