Words and photos by Darr Hawthorne

A couple of years ago we did a tech
feature on replacing the stock
clapped-out GM transmission in our
project 2002 GMC Sierra half-ton
pickup. Over the years we have
installed a lot of aftermarket parts
on this truck driven hard and often.
When the stock trans gave up at
140,000+ miles we decided to
replace the stock unit with a
purpose-built trans. 

After talking to some fellow racers
about transmissions we opted
for a TCI 4L60E.  We had the
trans installed and at the same
time made some needed chassis
modifications to make our GMC
tow and handle better especially
on those long hauls over the
“Grapevine” to Bakersfield,
California. With the odometer just
crossing 190,000 miles, it’s time for an
update on our GMC Project Truck TCI trans after putting 50,000 hard
miles on it without any failures.

This truck has been around the block a few times, but with the economy we have now, replacing a tow vehicle or daily driver is a lot more of a problem for hot rodders than it has been.  So extending the useful life of a tow or working truck is worth the time and effort involved for most of us.