On Tuesday I had the Automatic transmission fluid/filter change. Drop transmission pan and drain out fluid. Replace filter, clean pan,and install new gasket. Flush transmission fluid. Filter kit, fluid and labor cost $145. On Thursday, with less than 50 miles driven, the differential pinion gear lost its pin, it flew out of the differential, cracked the housing and ruined the transmission. This from a long trusted mechanic, "It's purely co-incidental, I didn't do anything wrong". I got a quote to replace with rebuilt transmission and quote for used transmission, with used being 1K cheaper. I don't like co-incidence. If it's more than that, how do I prove and get him to pay? This is a 99 Camry LE 2.2L in-line 4, with a A140E/L transmission.

 

Have never heard of a differential exploding after a trans flush. This stated cannot state the exact cause without looking at the trans. It is possible for a diff to fail but extremely uncommon.

The differential (the part that failed) and transmission (the part with the gears that shift) have separate fluid compartments.

The trans fluid is of course in the trans pan and drained by the plug in the pan. The differential fluid is in the differential housing; this is the housing the axles attach to.

The trans fluid poured into the trans dipstick does not go to the diff. The diff housing needs to be refilled separately if was drained.

The differential housing has a drain plug underneath it and a fill plug behind it (faces the firewall),

Although cannot state what happened, one thing to check is if the diff fluid was drained and not refilled. The differential would then be running with out fluid.

Was the trans making any noise such as grinding before the diff failed?

If the trans was hot rodded the diff can fail but again uncommon.

 

My thoughts are the same. I'd venture to say the differential side was drained but not refilled.

JJ