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2008 Jeep Liberty Transmission Issues: P0733 Code, Black Fluid, Gasket Burnt Out - What to Do Next?

Model: 2008 Jeep Liberty Fault Code: P0733 Posted: 2016-07-16 22:12

I recently purchased a 2008 Jeep Liberty four months ago. Today, I received the P0733 diagnostic code, which indicates an incorrect gear ratio in third gear. After inspecting the transmission, I found that the transmission fluid was blacker than oil used for 20,000 miles and the gasket had burned down completely. I replaced the transmission fluid, filter, and gasket. The vehicle initially started fine after a 10-minute run and drove smoothly. However, two hours later, it began running poorly—gears are slipping, and the vehicle is now in limp mode with very limited power. I'm seeking advice on whether I should replace the TCM sensor or if there's another more likely cause. Any insights would be greatly appreciated.

Related fault codes
P0733
Comments (6)
Anonymous 2016-07-17 09:10

A few questions to clarify: Are you using a scanner that can read all diagnostic codes, including manufacturer-specific ones? What codes are currently present—only P0733 or others? It's highly unlikely the TCM is at fault. Make sure you're using the correct transmission fluid for your 2008 Jeep Liberty—ATF4 is recommended, not a universal fluid type. The output speed sensor is relatively inexpensive and may be worth replacing instead of spending time troubleshooting. Note: At $10, it's more cost-effective than a half-hour diagnostic test.

Anonymous 2016-07-17 12:16

I used ATF4 as recommended. There was another code that appeared alongside P0733—likely related to an incorrect gear ratio in second gear. The scanner I used is fully capable of reading all vehicle-specific codes. After clearing the original codes, no new errors have reappeared.

Anonymous 2016-07-17 12:36

If the transmission won't shift at all and there are no active diagnostic codes, check the 'pending' or 'memory' section of your scanner. The issue might not yet be fully set as a code but could be stored temporarily.

Anonymous 2016-07-17 12:40

The vehicle does shift, but not smoothly—gears don't engage fully and tend to pop out easily. I'll check the pending codes section of my scanner to see if any issues are still present.

Anonymous 2016-07-17 13:42

"I do not think it is output but @10$ eliminates it vs .5hr test" — where can I find a $10 output speed sensor for the 42RLE transmission? I've been searching online, but no affordable options are showing up.

Anonymous 2016-07-17 16:17

The price for a 42RLE output speed sensor (OSS) is around $42 in retail markets. However, some auto parts suppliers or trade channels may offer it at $10—this could be the cost-effective option compared to a full diagnostic test. The suggestion was that replacing the sensor at such a low price might be more practical than spending time diagnosing.