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Gary, ASE Certified Technician
Category: Subaru
Satisfied Customers: 1052
Experience:  Senior Technician
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08 subaru outback 2.5 AWD. Our customer had a used

Customer Question

08 subaru outback 2.5 AWD. Our customer had a used transmission installed.The AWD light blinks when you get moving the speed sensors are reading that the front sensor matches the speedometer, but the rear is reading 10-15 mph higher.
Submitted: 1 year ago.
Category: Subaru
Customer: replied 1 year ago.
the car also has a shutter when you accelerate over 40 miles.
Expert:  Gary replied 1 year ago.

Hi there,

Sounds like the used transmission has the wrong ratio front diff in comparison to the rear diff.


Customer: replied 1 year ago.
Is there a way to check that?
Expert:  Gary replied 1 year ago.

The easiest way is to get the transmission serial number, and check with a Subaru dealer.

They can decode what ratio is inside if it is still stock.

Give them your VIN as well and they'll tell you your rear diff ratio.

Don't drive it until you get this sorted.

Hope this helps.


Customer: replied 1 year ago.
as it stands, the number on the used trans is TZ1B8LFEBA, going by the vin, the dealer says trans is supposed to be TV1B8MFEBA. Both numbers are for the 08 outback 2.5 non turbo. The dealer i was talking to would not tell me or did not know what the difference is. Can you find out what the difference is and let me know if it could cause the AWD light and speed difference?
Expert:  Gary replied 1 year ago.

I can't tell differences for you from trans serial numbers.

I can only suggest asking Subaru how many different diff ratios are available for your Model/year.

The numbers mean nothing if somebody else has rebuilt the donor trans with a different gear set.

10-15 mph is a big difference, even at 55mph.

Have you asked Subaru about this?