Odometer, trip meter discrepancy

[jatree]

Over the last two 200 mile segments I've driven, I've noticed that the Trip Meter is about 10 miles different than the Odometer difference.

For example,
Odometer will go from 150,000 to 150,200
Trip meter will go from 0 to 210

Which one should I trust and why is it happening? After noticing, I tracked the last 40-50 miles and so far they are exactly the same. So I'm guessing it's a small difference adding up over time.

Other info:
Tire size = 265/70R17

I didn't find anything in search so wondering if anyone has seen the same.

 

[60 toy ota]

How sure are you that there is a discrepancy, given that they've been in sync for the last 40-50 miles?

The trip od is mechanically driven by the odometer, so I would trust the actual odemeter more. If they are off it's likely due to slippage in the gears between the two. But that slippage is usually more frequent and consistant when it does occur, often due to the reset button cracking the plastic the digits are mounted to (I try to be very gentle with my reset button).

Total off the hip guess, but if there is indeed an intermittant discrepancy, it could be because the grease is old and cakey, and when it is cold if offers just enough resistance to cause the gears to slip. Then when the cab warms up the gears turn more easily and stop slipping?

But I'd double check that there's a problem in the first place.

 

[jatree]

Thanks for the explanation - that seems like a great guess. I'm pretty sure it's happening because I started tracking both Odometer and Trip Meter at every fuel up in order to track MPG's and see how my recent work was impacting the engine.

The intermittent part threw me off. Just yesterday I watched the Trip Meter match mile markers to the tenth of a mile and same for the Odometer. However comparing my last two fill ups, the Odometer indicated I'd driven 200 miles in between and the trip meter was 209.7.

 

[60 toy ota]

That would be extremely odd for the trip to read higher than the odo. Keep an eye on it and let us know