Frequently Asked Questions
Since we know you have loads of questions here are some of the most frequently asked.
Transmission Gear Ratios
The most common and desirable Street and Performance Transmissions
The information below is considered to be accurate; however, your specific transmission may have been modified either at the factory or post production therefore these are guidelines.
1st |
2nd |
3rd |
4th |
|
| TH-350 | 2.52 | 1.52 | 1.00 | |
| TH-400 | 2.48 | 1.48 | 1.00 | |
| TH-2004R | 2.74 | 1.57 | 1.00 | 0.67 |
| 4L80E | 2.48 | 1.48 | 1.00 | 0.75 |
| TH-700R4 | 3.06 | 1.62 | 1.00 | 0.70 |
| 4l60E | 3.06 | 1.62 | 1.00 | 0.70 |
| AOD | 2.40 | 1.46 | 1.00 | 0.67 |
| 518 | 2.45 | 1.45 | 1.00 | 0.69 |
Q: I want to convert my 3 speed turbo 350/400 automatic transmission to a 4 speed Overdrive. Is a computer neccesary?
A: No. The 700R4 / 4L60 requires only a 12 volt connection which controls the torque converter clutch solenoid. The transmission shifts via hydraulic pressure.
Q: What is Lock-Up?
A: Lock-Up refers to a clutch inside the torque converter that when applied, locks the internal components of the converter together to achieve zero slippage in the converter. These type converters are found almost exclusively in overdrive transmissions but were also incorporated into some 3 speed automatics with electronic control. 'If you choose, you can also have a manual lock-up, which is great for high performance or towing. Use it when you like. Ask us how.'
Q: If I do a transmission conversion will I need to modify anything?
A: Yes. Although swapping a TH350 to a 700R4 is a pretty straight forward endeavor, there are things to keep in mind. The driveshaft must be cut 3 inches. Taking into consideration you are swapping a short tail TH350 the 700 comes in at 2 7/8" longer... this requires the shaft to be cut then balanced. Some applications do not need this modification as in the 200R, which retains the same length. There are cross member mount holes, but before you press on to doing anything, first do not feel intimidated. We will gladly assist you in accomplishing your goals with little pain.
Q: Will changing my tire size alter my speedometer accuracy?
A: Yes... Tire Diameter will alter your speedometer and be incorrect. The Drive gear on the Shaft needs to be changed and matched to the cable gear to the Speedo. Below is a calculator to find out what your actual speed is if you change tire size. Width has no effect... Tire Height/Diameter only will.
We are actively looking for more questions so we can help answer the many thoughts you all have. Please submit any... We are always looking to make new friends.
