In this article, we go over some of the most common problems that affect Saab vehicles with automatic transmission.
No 3rd gear or stuck in 1st or 3rd gear
Saab 9-7 vehicles have a 4L60E 4-speed automatic transmission, which can suffer from problems when shifting to higher gears.
In some cases, the transmission will only shift to 2nd gear, while 3th and 4th gear will not be available. Even more severe problem is when the transmission stays stuck in 1st only, losing the ability to engage other forward gears and reverse. The problem can be intermittent or constant and usually does not trigger any warning lights.
Possible causes and solutions:
- Excessive wear of the 3th-4th gear clutch pack, which prevents the engagement of 3rd gear. This is a very common problem, which happens due to a fluid leak within the piston that engages the clutch. Aftermarket upgraded kits available.
- Damage of drive shell collar or excessive wear of collar splines, which prevents gear changes and limits the transmission to 1st gear only. Usually, this will happen suddenly and will remain that way even when the car cools down. Drive shell renewal is the only way to fix this issue.
No reverse after overhaul
First-generation Saabs 9-5 that use a 50-40/42LE 4-speed automatic transmission can experience loss of reverse after the transmission has been removed and refitted to the vehicle. In most cases, it will not engage reverse gear when selected from neutral but works if the gear lever is quickly moved from drive to reverse.
Possible causes and solutions
- A common problem is mismatched connectors for the turbine speed sensor and output speed sensor. This is a very common mistake that happens because these sensors are near one another and have similar connectors. This prevents the engagement of reverse gear, as TCU registers turbine speed as transmission output speed. The easiest way of testing is to disconnect the turbine sensor and see if this affects reverse gear engagement.
Delays during gear shifts
Saab 9-7 vehicles have a 4L60E 4-speed automatic transmission that can suffer from intermittent gear shift issues.
In most cases, this will show as delayed or failed gear upshifts while accelerating. Sometimes, the transmission will fail to downshift during accelerations or when slowing down. These issues usually trigger the check engine light; there will be a corresponding error code stored in the vehicle's DTC memory.
Possible causes and solutions:
- Throttle position sensor that is faulty and sends false data to the TCU. In most cases, ECU will recognize this and trigger a check engine light. Most diagnostic tools can monitor the operation of the throttle position sensor.
- Excessive wear within the TCC regulator valve, resulting in harsh shifting from 1st to 2nd gear. If this happens, the check engine light will be illuminated, and there will be a P1870 code stored in DTC memory. As this is a fairly common problem, there is a range of rebuild kits that come with upgraded components.
Shift flares and harsh downshifts.
Many Saab vehicles use a 5-speed automatic transmission designated as Aisin AW55, which can develop a very common issue.
Drivers will experience symptoms like shift flares that occasionally happen on accelerations or harsh downshifts. This affects shifts between 2nd and 3rd gear. In the initial stages, this issue will be more noticeable while the car is cold but gets more severe with time.
Other symptoms include an illuminated check engine light, meaning there will be a trouble code stored in the DTC memory.
Possible causes and solutions:
- Excessive wear inside valve body bores, which results in transmission fluid pressure drop. In some cases, depending on the position of the wear, this can obstruct the valve movement. The cause of this issue is that the material for the solenoid valve material is harder than the valve body itself. When examining the valve body, check for wear marks and replace it if there are any.
- Mismatched control valves during transmission repair. As there are two different variants with or without a control spring, this can result in sporadic 2-3 gear shift issues.
Shift flares on moderate acceleration
Later, Saabs 9-3, with a 6-speed automatic transmission designated as AWTF-80, can develop an issue that will manifest itself as a prominent shift flare. In most cases, this will only happen on mild accelerations, while more aggressive ones will go without this problem. In some cases, there will be a noticeable delay when coming to a stop. Usually, there will be no other symptoms.
Possible causes and solutions
- Neglected transmission service intervals, which results in degradation of transmission fluid and clogged filter, caused by lack of fluid changes. This happens as a result of manufacturers' recommendation, which states that this ‘sealed for life’ transmission does not need any fluid changes. On high-mileage cars, this can cause issues that can be solved by a thorough transmission fluid flush.
- Excessive wear of bores inside the valve body, which causes intermittent losses of transmission fluid pressure. Being a common and well-documented issue, many transmission specialists offer rebuilt units with upgraded components.
These are some common Saab transmission problems. Note that just because you own a Saab, it does not meet that you will experience any of these problems.
If you are experiencing a problem with your Saab transmission, call the dealer or use a VIN decoder to find out which transmission is installed in your car. Then research the problems that affect that particular transmission.
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