This option is for you to send in your stock SCHA and have us modify your unit. We do not supply cores for the rebuilds, we need your complete unit to be able to modify it.
If you select this option you will need to send your unit in to us for inspection, once we find that it is in good condition we can perform the modifications. All Modified Shift Change Holder Assemblies are built to order. This item will ship in 7-10 business days after approval of used unit.
IMPORTANT NOTE: REBUILD option will include a new Cryoheat treated interlock only, not the shift piece. If you want a new oem or Cryoheat treated shift piece this will be an additional cost and you must contact a SF sales representative.
SpeedFactory (SF)-Modified Shift Change Holder Assembly for B-series hydraulic transmissions!
1st off, what is the SCHA, and what does it do? The SCHA is located inside the transmission housing, and is the internal mechanism that actually moves the shift forks into position, engaging each gear as it is selected.
Why do you need this? Because you can't finish a race with a broken gearset or the inability to get it into gear due to a damaged SCHA. Because yours is wearing out and bending, and you want to get to it BEFORE it breaks and you ruin a transmission and gear set, especially if you're running a dogbox and big power. This also works great with stock transmissions and will help improve shifting, especially the 2-3 shift. Just push the shifter forward, and it will automatically drop into 3rd gear! It pulls the shifter to the center position with authority, to help eliminate the dreaded 1-2-1 or 2-3-2 mis-shift!
We've made improvements and fixed the parts that break so that you can make better and more consistent shifts, lower your ET's, and save your transmission! The SF-Modified SCHA is a vital component of a reliable transmission, and replacing it BEFORE it fails will save you money and frustration in the long run.
Many people experience problems with missed shifts and/or damaging expensive dogs and syncro teeth, and having difficulty finding the cause of these issues. Frequently a failed stock SCHA is to blame, and this product was designed to address the serious need for a stronger, improved SCHA in these transmissions.
We've spent many hours locating the cause of these issues when they occur in a properly assembled transmission through careful inspection and testing. The stock SCHA has been indentified as the source of these "mystery" issues in most cases. The problem areas of the stock SCHA have been identified and we have modified/replaced these parts accordingly, and tested this modified SCHA in our drag cars with great success, as it has eliminated all issues that we had previously experienced.
There are many modifications made to the SCHA, each addressing a known issue.
The stock shift change arm is the biggest weak link. The stock arms are made of poor quality stamped steel, and are often damaged (stress cracked or bent). This piece has been replaced with a heavy-duty CNC machined tool steel arm that will not bend or break like it's stock counterpart. A damaged stock arm often goes unnoticed as the damage can be difficult to spot without disassembling the SCHA and/or checking for proper operation of the internal components through assembly and testing utilizing a windowed transmission case. Many people have damaged part after part and experienced issues shifting without realizing that a damaged shift change arm is to blame. Then, replacing it with another stock unit has resulted in the same problem occuring again, usually within a short period of time.
PRODUCT UPDATE as of 05/17: After a year of successfully testing a new process in our own race cars, we are proud to announce an update that results in an even better product! The shift piece is prone to wear and the interlock is prone to wear and bending as well, which negatively affects the operation of the SCHA and can result in increased difficulty shifting and insufficient fork throw. The interlock is no longer welded and braced - the interlock and shift piece are now CryoHeat treated and micropolished. We've found that this process greatly reduced heavy wear rates seen in these parts, gave smoother shifting action, and reduced shift fork "digging" into the interlock which eventually cases a delay in shift speed and bent interlock. IMPORTANT NOTE: REBUILD option will include a new Cryoheat treated interlock only, not the shift piece. If you want a new oem or Cryoheat treated shift piece this will be an additional cost and you must contact a SF sales representative.
The SCHA base is TIG welded at multiple points where fatigue cracking and stock weld failure has been seen to create a much stronger assembly that offers more precise, improved shift action and will hold up under the abuse seen during aggressive shifting such as when used in a drag racing application.
In addition to these modifications, the shift select return spring has been upgraded with a much higher tension unit. This gives the shifter a more positive feel, and returns the shifter to the center position with authority. This allows for much easier 2-3 shifts as well as greatly reducing the chances of the dreaded 1-2-1 or 2-3-2 mis-shift, and does not require solid engine mounts to work.
Saving even one missed shift, damage to a dog ring or gear, or reducing damage to a syncro sleeve or the dog teeth on the gear itself is worth it alone. Not to mention a lost race due to a transmission that doesn't want to or won't go into a gear because of a damaged SCHA. The easier 2-3 shift and reduced chance of a 1-2-1 or 2-3-2 mis-shift is a great benefit as well.
This upgraded assembly is great for those who want to make sure each shift engages as it should, especially under racing conditions, or for anyone desiring a better functioning gearbox with greatly improved reliability!
All Modified Shift Change Holder Assemblies are built to order. This item will ship in 7-10 business days after order is placed. One year limited warranty against manufacturing defects. This does not cover damage from abuse such as a bent base or interlock, or normal wear from use.