We added this special section for the Volvo vehicles that use the 4T65EV/GT transmissions. The vehicles that use this transmission have the I6 engine in either naturally aspirated version or the T6 turbocharged version.
While most all other tech info and problems apply to the Volvo version 4T65E transmissions- there are more common problems that these vehicles experience specifically and ones that we have become aware of over recent years.
S80 and S80 T6 Model Years 1999-2005
"Service Transmission Urgent" light appears on dash:
When a transmission trouble code triggers this light will come on. Often times this light turns on due to clutch slippage and ultimately the wrong commanded gear ratio is detected by the TCM (Transmission Control Module). You may find that you lose 4th gear and only have 3rd gear until you restart the vehicle. It is very important to have your vehicle scanned to check for codes and also road tested if possible to find out what is causing the code to set. Volvo vehicles unfortunately do not have the best aftermarket support for scan tools- so you may only be able to get generic codes read and not actual data or specific Volvo data and code descriptions.
If you have codes checked and find an incorrect gear ratio code or shift solenoid hydraulic/mechanical fault code then you are likely looking at a transmission rebuild. We have numorous customer requests for solenoids when these codes set but rarely are the shift solenoids to blame for this. Often times the 2nd clutches are badly burned and damaged in these vehicles as well as 3rd clutches. When they are burned and glazed they will no long hold as they should when applied and slippage occurs. With excessive slippage you will experience long shifts that slide into each gear and seem delayed, and also you may even feel the transmission slip out of gear as you slighly accelerate. When the TCM detects that the commanded gear ratio did not occur then it blames the shift solenoid for mechanically not doing its job- even though it likely is. The TCM doesnt know any better and is programmed to set a fault code to best suite the condition, it knows nothing about the actual physical condition of the transmission. Properly diagnosing these transmissions with a scan tool and watching live data can be very important to determine the real cause of the problem, and also whether you just need a few parts or a rebuild to fix it.
This is a fairly common problem that will gradually occur. The cause is almost always badly burned 2nd clutches that have warped and even welded themselves together. Geartrain failure will also cause this but not as common to see.
Long sliding shifts:
This problem is one that most 4T65E transmissions experience sooner or later. The factory design didnt allow enough compensation for wear- so the result is normally poor shift feel and long or lazy shifts, especially the 1-2 shift which leads to eventual failure. The 2nd clutch clearance from the factory is set very loose and as wear occurs this will grow and make the shift feel worse. General wear inside the transmission also causes apply pressure to drop with age so these two problems add up and this is one area that does not need to be short handed on pressure. The 1999-2002 models are also well known for pressure control solenoids prematurely failing and can cause low line pressure that the TCM cannot control. Often times if the transmission has low mileage and is in good internal condition you can upgrade the factory 1-2 and 2-3 accumulator parts with ones from a Transgo Shift Kit and this is a good aid to help get clutches to apply when they should. A shift kit does not make up for excessive clutch clearances but does speed up the time the clutch will apply.
Loss of movement, Possible whine noise:
Another problem that we see often with these models is complete loss of movement after driving and wont move in any shifter range. Shutting the vehicle off for a short period of time and restarting may allow it to move again but only for a very short distance. Typically the source of this is a plugged filter due to torque converter and/or torque converter clutch failure and the debris finds its way to the pan and gets sucked up into the filter. Dropping the lower pan for inspecition often shows heavy amounts of dark colored debris in the pan. If you remove the filter and cut it open you will find the debris trapped in here also. Excessive clutch and geartrain damage can also cause the filter to become plugged up but not as common to see.
Grinding or Crunching noises, Loss of movement:
This is a problem that is not too common to see on these vehicles but since we have seen a few, moreso in the GM vehicles, it should be mentioned. The final drive (differential) in these transmissions serves two functions. First- it is the final drive gear ratio of the transmission and final section of geartrain to transmit power to the axles. Second- it serves as the differential by means of spider gears connecting the left and right side axle. The differential section of the final drive is rarely at fault on the Volvo models, but the final drive section has been found to shred itself and cause loud grinding or crunching noises followed by loss of movement. Dropping the lower pan will reviel shards and chunks of metal from the gear teeth being chewed up and broken off. The fluid return drain hole for the final drive section drains straight to the lower pan near the magnet and end of the filter so it will be very easy to see the damage that ends up in the pan.
No 4th Gear:
The 1999-2002 models had trouble with this due to the 4th clutch hub/shaft stripping out where the splines engage a gear inside the transmission. It may work perfectly fine then out of nowhere you have no 4th gear and restarting the vehicle does not bring it back. As mentioned above- no 4th gear can also be caused if a trouble code sets and the TCM puts the transmission into a limp mode but you can typically shut the engine off and restart and this can clear it up for a short while. If the 4th clutch hub/shaft strips out then mechanically you lose 4th gear and it needs to be repaired. Around 2003 all of the 4th clutch hub/shafts came with heat treated splines to remedy the problem. Several aftermarket parts are also available with the heat treated splines to address this problem and to date we have not seen one of the improved offerings strip out.
Engine Coolant inside the transmission:
There have been several reports of this being found in the Volvo models. While the cause is often blamed to be the radiator and/or internal cooler failing and leaking- this can also be causes from excessive metal debris from a failing torque converter. It will act as a constant abbrasive on the cooler passages and can eventually wear a hole through and cause an internal leak. By the time the problem occurs you blame the cooler for causing the transmission to fail but it could have been a failing torque converter and large amount of fine metal debris flowing through the system that caused the cooler to fail. In any event the radiator must be replaced and we suggest almost all Volvo models have the radiator replaced due to heavy contamination.
XC90 T6 Model Years 2003-2005
Most of the S80 problems listed above also apply to the XC90 vehicles with the I6 engine and 4T65EV/GT transmission so we wont list them in this section. The XC90 vehicles have a few of their own problems that we have seen and they are listed below.
Cooling system failure:
Like the S80 models, the XC90s have shown to have their share of cooler related problems and again I am more inclined to these problems being related to excessive debris in the system. The XC90s also have an external cooler that is plumbed in-line with the radiator for additional cooling and is of nice quality. It is mounted very low and can collect a bit of dirt and debris, also rocks and other chunks of debris you don't plan on running into. As with the S80 models- if the transmission has failied then there will be a lot of debris in the system and the cooling system needs to be replaced. We have installed aftermarket coolers on these vehicles and also sold many to customer wanting to avoid the cross contamination concern with a failing radiator.
Drivers side front axle leaking:
This is not a problem that you may even know is going on, but one that should be taken seriously and inspected. We ran into our first XC90 with this problem not too long ago and was shocked at what we saw. There is a bolt that retains the outer part of the axle / CV joint to the wheel hub. This bolt is accessable once you remove the front wheel. When you remove the bolt you experience dark colored transmission running out that seems like it never wants to stop. There is a Volvo dealer service bulletin about this problem also. The cause is a cup plug that becomes loose in the inner CV hub that goes into the drives side of the transmission- this is only a problem on the drivers side. When the plug falls out of place the transmission fluid enters the axle and cv grease mixes and goes back into the transmission. The 2003-2004 models used a hollow CV shaft that connects the inner and outer CV joints, so when you remove the retaining bolt in the wheel hub the transmission fluid will run out of this hole. The 2005 model year is said to have a solid axle so you wont have the fluid leak BUT this problem can still occur and the cv grease will mix with the transmission fluid and contaminate the transmission. Volvo does have a revised axle that addresses this problem and from what we have found is a dealer only item and in the $500+ price range. This is something that definately needs to be investigated any time a transmission is removed for repair from an XC90!
Grinding and Clunking noises AWD models:
This is not a problem we have ran into at our shop but one that other have. The cause may be a damaged bevel-gear section of the transfer case. The transfer case is used on the AWD models to transmit power from the final drive of the transmission to the drive shaft that connects to the rear axle. There is a chain drive section and a bevel gear section of the transfer case and they both constantly spin with transmission output speed. They have their own designated fluids so must be checked independently of each other- in addition to the transmission fluid level which is also seperate. Thats right- there are THREE different fluid levels to check in this system. Low fluid levels from a leak is going to eventually cause damage to the transfer case so this is something that should not be overlooked during services and maintenance on the vehicle.
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