77 GMC Sierra diesel 4x4 questions

I have just purchased a 1/2ton 77 GMC Sierra 4x4 diesel truck that I
cannot even get VIN decoders to find. It is titled as a 77 GMC Sierra
and has the appropriate TKZ VIN beginning, but even the GM manuals say
there was no such truck until 1978. Is it possible this was custom
ordered with this engine? It does have the original diesel dash and is
obviously originally a diesel truck as all of the diesel lines are
original. The VIN code digits seem to indicate that the truck was
manufactured in 1976, but once again none of the manuals or VIN
decoders think such a vehicle existed.

So to sum up, I have a 1977 truck that was manufactured in 1976 with
an option package that appears to have not been available until 1978.
Anyone have any clues as to how this could happen? The truck does not
appear to be stolen or rebadged and has a clear title. Purchasing
parts for this thing is a bear as you never know what year to tell the
autoparts store you have!

In particular I need to know what size backspacing wheels I can fit on
this thing as I do not care for the 15" aluminum wheels it currently
has. It has 6 lug wheels and I would love to fit some of the current
GMC steel wheels onto it.



Aegeas

[email protected] (Aegeas) wrote in message news:<[email protected]>...
> I have just purchased a 1/2ton 77 GMC Sierra 4x4 diesel truck that I
> cannot even get VIN decoders to find. It is titled as a 77 GMC Sierra
> and has the appropriate TKZ VIN beginning, but even the GM manuals say
> there was no such truck until 1978. Is it possible this was custom
> ordered with this engine?

No. It could have been a preproduction or pilot vehicle or a demo.
It's likely it's not a true prototype per se, because they have a
different VIN plate and GM is pretty good about them not getting out.
It's also possibble it was a production line Kermit-if a diesel truck
was available but not that trim package, it could have been an
accidental-on-purpose error build done for some plant or union guy.
Every once in a while these get through the line, sometimes management
catches them and it's someone's ass. I think boredom relief is a big
motivator for Kermits.

Supposedly they are called Kermits because one early vehicle was a
bright green car with a black dash and carpets and red seats.
Management saw it in the lot, realized you couldn't order that
according to the book, and intercepted it. It turned out it had been
'engineered' by a retiring foreman whose daughter really liked Kermit
and thought that it would look like Kermit with his mouth wide open.
Management allegedly had Kermit done away with and the foreman was
allowed to pay for the car to protect his pension.