The 6T70 is a six-speed automatic transmission. This transmission was made by General Motors and Ford. The 6T70 is a successful transmission powering many vehicles. However, it does have a few common problems which may arise over time. Let’s look at ten common problems with the 6T70 transmission:

Transmission Fluid Overheating

A common issue with the 6T70 was the overheating of the transmission fluid. The issue was the result of a faulty circuit.

Problem with Brake Switch Circuit

The brake switch issue was another problem with the 6T70. This was also because of some internal problems with the brake switch circuit.

Issue with the Planetary Gear System

The issue which is a grave concern in the 6T70 transmission is a problem with the planetary gear system. Once the planetary gears become faulty, the gear ratios are incorrect. This causes problems in accelerating and gas mileage, climbing steep slopes, etc.

Shift Solenoid Failure

This is a common problem with all auto transmissions and also with the 6T70. Once the shift solenoid fails, the gears don’t change.

Output Shaft Speed Indicator Failure

The output shaft speed indicator is responsible for determining the speed at which the drive shaft is spinning or the output of the transmission. This is also known to fail in the 6T70 transmission.

Torque Converter Failure

The torque converter failure is again a common issue with auto transmissions. The 6T70 also has a problem with the torque converter. Once this fails, the gears don’t change.

Gear Slipping

There are also problems with the gears slipping in this transmission. This is either because of a solenoid failure or because of the planetary gear system issue.

No Reverse Gear

Due to solenoid failures the reverse gear may fail to engage. The solenoid failure is not a huge expense but its best to have it repaired immediately.

No Gear Shifting

This is often caused by the brake switch or a torque converter failure.

4X4 Not Engaging

Another issue with the 6T70 was with the 4X4 system. Some of the Crossover Utility vehicles that this transmission was used in were not able to go into 4X4.

So, if you drive a vehicle with a 6T70, do keep an eye out for such problems.