Improving the performance of your 700R4 rebuild comes with a basket-full of benefits. For starters…
An upgrade will make your transmission powerful enough to handle drag racing, while at the same time offering an enjoyable driving experience around town. This is because there will be minimal or nonexistent sluggishness in shifts to impact on power.
On the other hand, it’s worth noting that you have the choice of changing the transmission entirely. But we all know how expensive a change can be, hence, upping the performance is a cheaper alternative to getting a more enhanced performance.
Therefore, if you have a 700R4 rebuild and you’re ready to give it a boost that will result in high-level performance, work with us and we’ll show you how to get started. But get this first!
Modern vs. Automatic Transmissions
Unarguably, modern overdrive transmissions are controlled by computers, which differs from older automatics like the 700R4 that rely on a valve body to be mechanically controlled. It, therefore, follows that a change in certain parts of the valve body can improve its performance. It’ll be able to provide firmer shifts, while at the same time-saving power.
Accordingly, one major part of the 700R4 valve body you’ll want to focus on is its TV cable, since this transmission may be damaged as a result of a poorly adjusted TV cable. The TV cable helps in adjusting the internal line pressure as well as part throttle shifting
A TCI Automotive Constant Pressure Valve Body kit can help you to work on the TV cable. What the TCI system does is to add parts that will maintain the accurate line pressure every time, and this means there’s no need to struggle in making a perfect adjustment to the TV cable.
Another kit that may prove useful is a lockup wiring kit. This kit offers two possible options where you can either lockup the converter manually whenever you want, or lockup the converter while in Fourth gear, automatically. Now pair these kits with a powerful torque converter and you’ll be able to turn even the most sluggish 700R4 rebuild into a faster and more powerful transmission.
Boosting the Performance of Your 700R4 Rebuild
Here are the simple steps that will help you to improve the performance of your 700R4 rebuild:
1. Take Off the Pan and Filter
You need to take off the pan on the 700R4 to expose the large flat filter beneath it. You can then proceed to remove the filter and its seal before disposing of both. Once the filter is off, you’ll be presented with the valve body. This component controls the shifting of the transmission.
2. Remove the 1-2 Accumulator
Take off the 1-2 accumulator by unloosening the bolts that secure it in place. These bolts are to be separated from others since they are unique to the accumulator.
3. Remove the Auxiliary Valve Body
The next step is to take out the auxiliary valve body while ensuring that the stock check valve is not lost because you’ll still have a need for it.
4. Unbolt and Remove the Throttle Pressure Mechanism
Proceed to unbolt the throttle pressure mechanism and then remove the component. Also, the wire cable linkage should be disconnected as the mechanism is pulled up and the bolt securing the detent roller spring assembly is disengaged.
5. Remove the Valve Body Bolts
Any leftover valve body bolts can now be removed. Next, the valve body, gasket, and separator plate can be taken off of the transmission. This will also enable you to remove the 3-4 accumulator piston and piston pin.
Both of these are situated beneath the region where the 1-2 accumulator was taken out of. And worthy of note, is to pay attention to the balls in the valve body, which may fall out in case you don’t have spares to serve as a replacement during reassembly.
6. Remove the Pressure Regulator
The transmission pump has a pressure regulator, and this component needs to be removed as well. Here, apply pressure downwards on the TV boost valve sleeve and use snap ring pliers to remove the retaining ring. Proceed to remove the TV boost valve sleeve, valve, and the reverse boost sleeve. What you’ll have is the top rows parts coming out where the lower row features the TCI parts.
7. Choose Spring Type
You can either use a silver spring to have a firm-style shift or attach the shim to the silver spring to get a street/strip-style shift. Another spring option is a gold spring without the shim and this offers hard shifts.
After the disassembly, you’ll notice some check balls from the stock valve body. These are reusable 1/4-inch silver ones that are four in number. There’s also a check ball in copper color and this may not be reused.
The TCI kit comes with spare check balls to ensure you can replace it if the original gets missing. You can then use the TCI instructions to reinsert the check balls while using some grease to hold them in place.
8. Insert a New Separator Plate and Gasket
A new separator plate looks similar but is still a bit different from the stock that came with the transmission. You can insert the new separator plate and gasket into the transmission, but it might be needful to modify the 3-4 accumulator using a self-tapping 1/4-inch x 20 Allen head plug. The accumulator piston and spring can also be replaced without using the black spacer.
9. Install the New TCI Valve Body
And after installing the gasket/plate assembly, it’s time to install the new TCI valve body. The rod for the valve body linkage can then be attached while ensuring that the valve is not forced and neither is the linkage bent.
10. Reinstall the Solenoid and Transmission Wiring
Also using the TCI instruction, reinstall the solenoid and transmission wiring. While at it, it may be useful to include a TCI lockup wiring kit to enable the torque converter clutch to enable flexible engagement of the automatic activation of the torque converter clutch in Fourth gear. This setup will also allow the clutch to disengage during acceleration or downshifts.
11. Reinstall the 1-2 Accumulator Assembly
The 1-2 accumulator assembly can be reinstalled after the piston has been mounted within the housing using a large orange TCI spring. The black spacer can also be installed if your ride is meant for street/strip applications. You can then fasten the bolts to 8 ft-lb.
12. Reinstall the Throttle Pressure Mechanism
It’s time to reinstall the throttle pressure mechanism and also the cable linkage while ensuring that the latter is well placed on the large lever. Other steps include running new wires, inputting oil pipe and tightening the bolts of the valve body to 8 ft-lb. In contrast, the detent roller spring bolt can be tightened to 10 ft-lb.
13. Replace the Filter
The TCI kit also comes with a filter seal ring and a new filter that you can use to replace the old one that was disposed of.
14. Revamp the Transmission’s Exterior
You can also revamp the exterior of the transmission by working on the servo. The parts of the stock servo can be replaced with the TCI parts before reassembling.
The Bottom Line
These are the easy steps to up the performance of your 700R4 rebuild without spending the extra cash to buy a new transmission. While these are DIY steps, you can employ the services of a professional if you’re unable to handle these procedures yourself. It’ll ensure that the transmission rebuild is just right and you don’t have a worse transmission than what you started off with.