Primary applications of the platform – those that are equivalent in basic RWD/frame structure to each other – existed from 1981 to 1989, and again since 2018.
Both of the Hummer models fully designed by GM – the H2 and H3 – have special platforms relegated to them. The H2 existed on a modified GMT820 platform withan entirely new midsection, referred to as GMT825. The H3 SUV rode on a variant fairly similar to the GMT355 platform, but was still different enough to be designated GMT345. The short-lived 2009–10 SUT H3, despite using a nearly identical platform to GMT345, was called GMT745 for its platform, keeping with the GMT700 midsize truck nomenclature of that time.
Vans
When the GMC Savana and Chevrolet Express vans were released in 1996, it was also announced that their platform moved to GMT, called GMT600. With the second generation of these models presented in 2003, the platform received small changes and was thus changed in name to GMT610, which is still currently in use.
Medium trucks
From 1990 to 2009, GM called the underpinnings of the GMC Topkick and Chevrolet Kodiak the GMT530 and later GMT560 platforms. These were discontinued in 2009 following the 2008 recession.
Other applications
While the aforementioned platforms are the ones model commonly referred to as GMT platforms, there have been other instances of the name being applied which are not for RWD and/or body-on-frame vehicles.
MPVs
For 1990, GM unveiled its first minivans, all of which were underpinned by the first generation of the U platform. This platform was given the alternate name of GMT199 shortly thereafter, beginning the pattern of expanded use for the GMT platform name. This pattern was kept for the 1996 second-generation and 2005 third-generation GM minivans, called the GMT200 and GMT201 platforms, respectively. With the 2010 introduction of the fourth-generation U platform, the designation GMT510 was planned for use. However, all of the GM minivans were dropped, ergo the name went unused. For its production from 2006 to 2011, the compact wagon-bodied Chevrolet HHR rode on the Delta platform. Despite this, its was internally given the designation of GMT001.
Crossovers
In 2001 and 2002, the Pontiac Aztek and Buick Rendezvous were introduced, respectively. These were built upon a shortened version of the U platform which underpinned GM's minivans. As such, they were given the GMT 250 name. For 2003, Cadillac released their first crossover, the Sigma-based first-generation SRX. being a luxury model, its was given the alternate platform code of GMT265. The successive generation SRX, depite being on an entirely different platform, was called GMT267. In 2004, with the release of the first-generation Chevrolet Equinox, the GMT 191 name was internally used to refer to it. Consequently, the GMT190 name was retroactively applied to the second-generation Chevrolet Tracker, which could be considered one of the Equinox's predecessors. GMT191 would also be used to refer to the Pontiac Torrent, which was released a year later. Somewhat confusingly, the next application of this platform was called GMT193, used exclusively for the second-generation Suzuki XL7, which was discontinued in 2009. However, confusion was resolved with the 2010 announcement of the second-generation Equinox, which was also called GMT192. In 2017, the third-generation Equinox went on sale, though it did not use an alternate GMT designation for its platform, and simply used the latest Delta platform variant D2XX. This decision, along with the equivalent shifts for the Enclave and Traverse models in the same year, made for the end of the use of GMT-platform designations for models that are not RWD and body-on-frame. For 2007, the release of the new Saturn Outlook and GMC Acadia, as well as the Lambda platform, occurred. Lambda itself was called the GMT960 series, with each individual vehicle it underpinned getting an alternate GMT-designation as well. The Outlook was given GMT966, and the Acadia GMT968. The next year, the Buick Enclave and Chevrolet Traverse were introduced, and given GMT967 and GMT561, respectively. Despite numerical similarity in nomenclature of these platforms to the GMT900/GMT560 platforms, there was no further relation, as these models were actually more similar to the other GM crossover platforms.