The Volvo Parts, Accessories &
Performance Specialists Since 1963

Automatic Transmission B4 Servo Cover Update AW55-50/51

Genuine Volvo - 107960

In Stock
Item Number
Genuine Volvo
Brand Classification
Units Per Car
One Year Parts Warranty
Product Group
Repair & maintenance
OE References
Genuine Volvo - 30751262, 30651771
Comp OE References
Genuine Volvo - 30751262

Product Description

It's ironic how this inexpensive part can save someone from a costly transmission replacement.

The early AW55-50/51SN five speed automatic transmissions have an issue with shift “flares” and other odd symptoms related to shifting in and out of 3rd gear. This usually reveals itself by a “missed” shift (somtimes called "shift flare") from 2nd to 3rd gear on a random basis.

This B4 servo cover update can solve these symptoms in many cases. Other times, it may take a software update or the flare problem has gone on too long and the transmission valve body is physically damaged.  It is possible for transmission damage to occur when the transmission engages harshly after a flare condition under heavy load.

Volvo has changed the design of the B4 servo cover multiple times and there are numerous Volvo service bulletins regarding it. The latest design is stock on later model years.

We highly recommend a transmission software upgrade prior to or in conjunction with the B4 servo cover update!  A fluid flush would also be an excellent idea.

The software for these electronically controlled transmissions has gone though many version changes over the years and has become much more refined.  A software upgrade can significatly reduce neutral to drive delays, shift flare and improve adaptive shift functionality.  If your car still easily rolls backwards when in drive while facing up hill on a slight slope, then you most likely need a software upgrade.  The neutral-at-a-stop while in Drive "feature" was removed with later software versions because it can cause damage when the transmission engages hard.  Recent software versions will also roll backwards but not freely (not like the car is in neutral.)

Transmission software upgrades must be done with a Volvo specialty shop using Volvo's VIDA application.

The B4 Servo issues usually don't affect 2004 and newer models, but some of these cars still have a variety of shifting issues that can be solved in many cases by a transmission software upgrade.

About Genuine Volvo

Everything IPD supplies under the "Genuine Volvo" designation are the factory original Volvo parts. These are the same quality parts that you will get in the blue Volvo branded box from a dealership. All Volvo supplied Genuine Volvo parts are made to specifications by Volvo and under their strict quality control guidelines.

Volvo relies on high-quality OEM manufactures such as Lemforder, Behr, Sachs, Bosch, Valeo, Siemens, VDO, Corteco, and many more to maintain its dedication to quality and safety.

IPD is the exclusive North American distributor for Genuine Classic Volvo parts outside of the Volvo Dealership network. We are proud of our Volvo heritage dating back to 1963, a reputation that is unmatched by others in the industry.

Many may not know this but Volvo in Latin roughly translates to "to roll".  The company was founded back in 1927 by Assar Gabrielsson and Gustaf Larsson as a spin-off from ball-bearing manufacturer SKF.  While the Volvo logo looks like the biology symbol for male, it's really the Swedish symbol for Iron. With a nod to its heritage in alloys, Volvo chose a logo that depicted a ring bisecting at one o’clock. Today Volvo is known around the world as one of the most iconic brands known for safety, longevity, and its enthusiast following.

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