Corvette Parts FAQ

lease read the following information regarding our parts and practices. If anything is unclear please email us with any questions, we are happy to answer anything we can.

info@tmodcustoms.com

 

ISO Shifter

Our most advanced shifter is the ISO Shifter which is available in 5% or 20% Reduction Ratios. Our 5% Reduction ISO Shifter features a very minimal decrease in travel between gears. Customers say it feels the way you wish the shifter did when the car was brand new. 

Our 20% Reduction ISO Shifter is more like a typical "Short Shifter"; the throw is not quite as short from gear to gear, but it is much easier to move through the gears; unlike a typical short shifter.

Anyone who drives a Corvette knows that vibration, NHV is an issue. The ISO Shifter features a Polyurethane Isolated stick that keeps vibration from the car from traveling up the stick and into the cabin and your hand. The ISO Shifter dampens vibration and NHV better than any other aftermarket shifter on the market. Both versions of the ISO Shifter are extremely smooth and precise and the same in every way aside from reduction ratios. We strive to create a shifter that is as extremely smooth and precise while remaining easy to move through the gears. We do not use springs or any other internals that bias the stick. The goal is to minimize the resistance against the stick as you move through the gears so the only friction encountered is what it takes to move the stick through the gates. The movement of our shifter is commonly described as "like the bolt action of a large caliber rifle". 

We use a bearing in the main pivot of our shifters. This bearing adds some of the precision or shifters are known for. Because we intentionally leave out any internals that may cause additional friction we also leave out any parts that would keep the stick clocked in a fixed position like a typical shifter is. It is important that you know the stick and knob of our shifters are allowed to rotate. This is unlike any other shifter on the market. For this reason if you decide to use a knob other than the one that is included we recommend sticking with something round or cylindrical to minimize the rotation of the stick and knob.  Please see our videos below for demonstrations of the shifter’s movement. 

We built every shifter and box by hand. We set them up on the tight side so they break in just right. You can expect your shifter and box to be tighter than you may expect until it breaks in. Typical break in period is approximately 100 miles.

ISO Shifter Kits includes upgraded Delrin Shifter Bushing, Delrin Knob and all Stainless hardware required for installation.

 

Upgraded Factory Boxes

Our Upgraded Factory Boxes are designed to eliminate the sloppy, vague feeling all Corvette shifters develop. 

Our upgraded factory boxes are available for Z06 or Non-Z06 cars. Torque Tube Bushings for Non-Z06 boxes are available in Polyurethane or Delrin. We recommend Poly for use on non track cars and Delrin for cars that see track time. Delrin offers a slightly firmer feel but does not dampen quite as well as Poly Bushings. Z06 boxes will retain the “solid” Torque Tube Bushings. 

The “foot” is the black plastic isolator that is glued to the fin on the bottom of the shifter box. When you receive an upgraded factory box it will be media blasted and ready to have the “foot” reattached to the fin on the bottom of the box. We recommend a small amount of silicone to secure the foot to the box; let it cure completely before installing the box. If your box did not have a foot on it when you removed it from the car it is important that you confirm that the foot did not remain in the car when the box was removed. The foot, when it is attached to the fin on the bottom of the box, is to be seated into the small notch on the side of the torque tube. This is the first step in installing the box in the car. Once you ensure the foot is seated into the notch on the torque tube you can slide the box forward and backwards to position it correctly. You must confirm that the foot is seated into the notch for the box to be installed correctly. Sometimes the foot will remain in the notch when you remove the box. If you are unaware that this has happened and attempt to install a box with another foot attached you will be installing a box and two feet. This will absolutely prevent you from being able to align the box properly. 

It is normal to hear air moving through the aluminum cap on our upgraded factory boxes. We seal up our boxes to prevent dirt and debris from corrupting the internal components. Drilling a hole to “vent” the cap will absolutely void your warranty, please do not do it, it will not make your shifter perform any better or move easier. 

It is normal for the shaft to be much tighter when you receive your upgraded factory box than it was when your box was removed from the car, or even tighter than a brand new box. You can expect it to be difficult to move by hand, that is how you want it. 

 

Sending in you Box and Core Charges

When you order an upgraded factory box you have two options. Option one is paying the core charge and receiving a completed box (this option is only available when we have boxes in stock). Your other option is to send in your box to be upgraded.

If you send in your box ahead of time to be upgraded please select "NO" from the Core Charge drop down box. Please complete checkout and we will wait to receive your box in the mail. Please include a note inside the package with your box including your Name, Order Number and Return Address you would like your parts shipped to. If your box is not received within 14 days we will refund your ENTIRE order and no parts will be shipped. If you are going to be late you can let us know via email, we will be happy to work out any issues. 

Once we receive your box we typically have it back in the mail within five days and ship via USPS Priority Two Day Shipping. We will send you the tracking via email when your parts are finished and on their way back to you. Sometimes tracking can be delayed two days, this is out of our hands unfortunately. 

Please remove and hold onto the black plastic "foot" from the bottom of your box prior to shipping. Your box will be clean when you get it back, ready for you to silicone the foot back in place.

If your box is excessively dirty please clean it off prior to sending it in. Boxes that are excessively dirty will be charged a cleaning fee of $12.00. 

Aside from the box, with the shaft in it, the note with your information is the only other thing we typically need to upgrade your factory box. Please do not send in your shifter, bolts etc. as they are not necessary. 

Our address for Upgrades and Core Returns will be located on your Order Confirmation, you will receive this via email after you have completed checkout. 

 

Billet Box

Replacing the factory shifter box is the single most important upgrade you can do to a manual Corvette and our Billet Box is the most convenient way to do it. The factory shifter box in C5, C6 and C7 Corvettes is the biggest reason the stock shifter is so vague and mushy. Upgrading to one of our shifter boxes will make even a stock shifter feel much better than the day it came off the factory floor. 

The Billet Box uses the same proprietary internals as our factory upgraded boxes but does not require you to send your box in to be upgraded. Instead we machine the entire box in house out of 6061 aluminum, replacing the cast aluminum stock box with a CNC machined part. 

The Billet Box does not include a shaft. Simply insert your shaft into the Billet Box and it's ready to go in the car. 

When you receive a Billet Box you will need to disassemble the box by removing the four 1\4-20 bolts and separating the two halves. Take note of the colored rings that are seated into the slot that the shaft rides in. Clean your shaft with brake cleaner and inspect for deep groves. If your shaft needs to be touched up, use a red Scotch Brite pad to remove any inconsistencies. Almost all of the shafts we have reconditioned have been brought back to service quality with red Scotch Brite pads. If you believe your shaft requires more work you should consider sending in your entire box to be rebuilt. If your shaft is salvageable we will recondition it on a lathe in the shop if you send it in. Please email for more information on this option. 

 After your shaft is cleaned and greased up, slide the rings onto the shaft in the order they came out of the Billet Box. There is no need for grease on the outside of the rings. Seat the rings into the slots in the lower half of the box and press down on the shaft to seat the rings. Take note of the pins in the lower half of the Billet Box; these pins will seat into the holes in the top half of the Billet Box. Line up the pins with the holes and confirm that the rings and shaft are seated properly and press the top of the Billet Box onto the lower half.  Now you are ready to bolt the two halves together and install them in the car.

Any shifter used in conjunction with our Billet Box will feel much smoother, tighter and less sloppy. We are proud to say that some of the fastest and quickest Corvettes in the world are running our Billet Boxes. Adding a Billet Box to your car will be one of your favorite mods. 

 

Delrin Shifter Bushing

This bushing replaces the factory plastic bushing on the bottom of the shifter and eliminates the slop between the box and the shifter while dampening vibration much better as well. This bushing is for use on any shifter that uses the stock plastic bushing. (Most aftermarket and all factory shifters.)