4R70W Transmission Problems
The 4R70W transmission is a highly reliable, electronically controlled overdrive with origins dating back to the early nineties. It is a high-performance unit that delivers high torque and reliability for thousands of miles.
But just like any other mechanical part, it, too, is prone to failure and specific problems.
Here are some of the 4R70W transmission problems that you should know how to diagnose.
Related article: 4R75E Transmission Problems
Most Common 4R70W Transmission Problems
There are multiple ways in which a 4R70W transmission can fail, but the most common ones are:
- It will not shift out of gear
- It will start to slip effortlessly between gears
The first problem often occurs when the car’s computer instructs the transmission to remain in a specific gear, no matter how much you rev the engine.
The second problem occurs when there is component damage inside of the transmission body, causing the gears to start “slipping” when you drive.
How to tell if the 4R70W transmission is stuck in gear
The 4R70W automatic transmission is electronically controlled through sensors and solenoids (located inside the transmission body).
If one of these sensors or solenoids fails, then the car will become stuck in a specific gear.
Besides staying in one gear when a solenoid goes wrong, the car may also feel underpowered and unable to reach higher speeds. The engine will start to over-rev because the transmission cannot change gears.
The power control module (PCM) on your car will also register a diagnostic trouble code, which may be solenoid related. The most common are:
- P0750 – Solenoid A malfunction
- P0755 – Solenoid B malfunction
How to tell if the 4R70W transmission is slipping
The most common way to diagnose gear slipping is when you put the transmission into the first gear and start accelerating; the car doesn’t move.
Another way to diagnose this problem is when the transmission downshifts into first gear at almost the same time as you stop the car. Typical first-gear downshifting happens before the car completely stops.
The reverse gear may also give out, even though the car goes forward just fine.
A common “gear ratio error” diagnostic code that may show up due to gear slipping is P0730.
Physically examining the transmission is the best way to determine gear slipping. It involves removing the transmission pan and checking for metal shavings.
If you find excessive metal shavings in the transmission pan, the transmission’s clutch plates are worn out, causing the gears to slip.
Other 4R70W Transmission Problems
Other problems with the 4R70W transmission include excessive pump noise and fluid leaking.
If you hear a thumping noise coming from the transmission, that may indicate a problem with the transmission pump. The role of the pump is to keep the fluid circulating and cool the transmission properly.
Leaks on the downside of the transmission may also indicate a problem. The most common cause of a leak is a bad gasket. Low transmission fluid levels are also an indication of a leak.
If you run into problems with your 4R70W transmission, it may be time to consider a rebuild. Here’s how much it costs to rebuild a 4R70W transmission.
