We followed this up with a series of high-performance parts from Sonnax that Galante knew would enhance this transmission’s ability to handle power while improving durability. This spring establishes the main line pressure.Īlong with the TCI valvebody, we also used a TCI master rebuild kit that includes all the clutches, steels, sealing rings, gaskets, O-rings, and seals. Galante added the mild silver spring to the pressure boost valve assembly located at the top of the pump assembly in this photo. This is the front pump assembly that was rebuilt to stock clearances. Galante obtained a good 30-spline core from which to start the process. The early 1982-86 transmissions employed a smaller, 27-spline input shaft that evolved in 1986-87 to a larger, 30-spline input shaft that is the best-suited version for performance use. Here, Galante has already loaded the clutches into the reverse input drum and alongside the drum is the Sonnax wider 2-4 overdrive band.īefore we dive inside our 700-R4 we should point out there are two different versions of the long-running 700-R4 four-speed automatic. We will also list all part numbers, including the complete TCI transmission that is available with the constant pressure valvebody.
#700R4 TRANSMISSION UPGRADE#
Despite this development, we will run through the modifications we made to our transmission if for no other reason than to illustrate the several performance upgrade parts available for the 700-R4 through both TCI and Sonnax. They do still offer complete transmissions with the constant pressure valvebody. Just as Galante finished the transmission and we began the story, TCI informed us that due to shrinking availability of acceptable 700-R4 valvebody cores, they would no longer sell these modified valvebodies as separate pieces. Our plan was to reveal upgrades to a late-model 700-R4 using the TCI constant pressure valvebody along with several Sonnax performance pieces. This is generally combined with a heavy-duty reaction shaft and bearing (right) that is stronger to prevent spline damage. The improved Sonnax SmartShell (shown) is redesigned to spread the load and increase its strength to prevent these cracks. One area where both the 700-R4 and 4L60E have problems is the reaction shaft shell (left) that cracks around the center spline area. But not everybody can afford the increased tariff of a fully electronic 4L60E and its required electronic control system. This should not be misconstrued as a sales pitch that a mechanically controlled 700-R4 is better than a 4L60E because, frankly, electronic control is far superior in nearly all aspects of transmission control. His positive comments about the TCI valvebody led to this story that will outline a few details on building an affordable 700-R4 for the street. Galante assured us that his experience with the TCI constant pressure valvebody offered firm but acceptable part-throttle shifts with a higher-than-stock stall speed converter but with sufficient line pressure to hold more than 500 hp with good durability.
This kit includes a band and filter along with all the necessary small parts. We used TCI’s Master Racing overhaul kit that includes all the seals as well as clutches and steels. We were skeptical since we assumed these offered extreme line pressure that would make part-throttle boulevard shifts a neck-stretching affair that would prove to be instantly annoying. That’s when our auto trans builder Jimmy Galante of RaceTrans in Sun Valley, California, suggested that he’d had great luck with converting a 700-R4 to use TCI’s constant pressure valvebody on street-driven 700-R4s. Read More: Turn That Crate Ls Engine Into A Vintage Work Of Art With Ls Classic Series By Lokar
#700R4 TRANSMISSION TV#
The overdrive trans promised decent street performance after a freshening but we were hesitant to employ it after witnessing a string of poor experiences with TV cable snafus on two different friends’ cars. But the harsh reality of life points to a powertrain that must be a bit more conservative that includes a carbureted small-block Chevy and a basic, 30-spline, 700-R4 four-speed automatic.
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