Catastrophic transaxle failure at 137,000 miles.

First, I'm sorry for your loss:

"It just froze" - so when the tow truck operator put it on the bed, the wheels did not roll? To have the transmission freeze like this suggests: (1) parking paw engaged, (2) catastrophic bearing failure, (3) gear tooth failure, and/or (4) loss of ATF fluid. The usual, older transmission failures were associated with MG2 stator shorts and did not seize the mechanical train.

The one case of a mechanically frozen transmission I'm aware of involved an object puncturing the transmission oil pan. The driver continued without lubrication until the gears, friction-welded themselves into a solid mass. It was a 2001-03 model Prius.

Where did this occur, City and State? The reason I ask is the terrain and climate in some areas are more severe on the Prius than others. Also, we might be able to suggests some known, Prius shops that do good work.

Were there any other damage? In particular, I'm curious if the under panels are there or were perhaps lost along the way. This would expose the transaxle to road debris.

Some historical data points, in 2005 I changed our 2003 Prius transaxle oil at 55,000 miles and found the ATF oil was on the verge of failure. Bought in Texas, the oil was opaque and smelled strongly of paraffin. It still holds the record for one of the worst samples tested. Subsequent samples gathered over the years suggest:

• 5,000 miles - first engine and transaxle oil change to remove initial debris left over from manufacturing
• 15-20,000 miles - second transaxle oil change, removes the residual
• 60,000 miles thereafter - works although some data suggests 90,000 miles after the 60,000 mile change

 

5k mile transaxle fluid change? I thought 30k first change was soon but my goodness....

 

I'd go with a junk yard tranny.

 

What happened is at 5k of service, microscopic analysis found small particles of transaxle case sealant and small metal shavings. Left in the transmission, the gears simply grind them into smaller, smoke-like particles. We also found the viscosity had dropped by 5% versus 15% as the threshold my oil testing service calls exhausted.

The transaxle sealant is the source of high Si found in the initial oil changes. The fine metal particles do not make sense unless either the cleaning is not as through as expected OR the initial operation 'polishes' the gear faces. In effect, the initial operation finishes polishing the gears. So I'm happy with the initial 5k change realizing there is about 15-20% that is carried forward with each change.

The 15K change dilutes the carry-forward and the late sealant beads and gear face polish. Thereafter, I'm good with going longer but I changed it more frequently to get some data points on the conservative side.

Going back to the original poster's problem, I would love to have someone with skill take the old one apart and diagnose the specific failure mode. Was the ATF fluid lost? Did it get so contaminated it led to early bearing failure? Did the parking paw mechanism fail? Did a gear lose one or more teeth? There are lessons to be learned.

Bob Wilson

 

I agree the OP gave much more intense use of the vehicle than average, but unless he was hot-rodding or otherwise abusing it (and regular maintenance suggests he was good to it), I would think regular intensive use is far easier on a vehicle than occasional use. For private aircraft, at least, there are known problems in having an occasionally used aircraft compared to ones in daily or weekly use. I would distinguish "hard, abusive " use from "regular, intensive" use. The former could plausibly lead to premature failure whereas the latter should not.

 

There is a balance. Using daily for 1 hour is much different than using daily for 4 hours.

Planes don't stop and start like cars in traffic. So 4 hours in a car delivering packages is not the same as a 4 hour sustained flight.

 

I would advise against using a Prius in this capacity. I'd choose a real econobox beater. In this line of work the car is a disposable item. That and the incentives one has are stacked against driving in a way that encourages best use of the car (max accel/deccel, lots of short trips, etc.) If I were you I'd get a junk yard transaxle installed, sell the car and replace it with a $4k - $5k Honda Fit or Corolla type. I'd allocate about that much as the annual cost of car replacement in this line of work. If you don't need to spend all of that, great. But I'd never, ever, use a new car, let alone a new Prius as a courier car. It just doesn't make sense.

[Note that this is not to say that the Prius (+v, c) doesn't have a use in the commercial world. In my area, just about ALL the newer airport taxis are Prius v. But that use is very different. The cars are generally making 20-30 mile trips after picking up fares and then getting dispatched to find another fare to bring back to the airport. From my understanding of the courier business, the trips are MUCH shorter with a much higher value placed on urgency.]

 

Can't agree. Prius has always been a good beater. New or used.

 

Which reflects European taxi use, and gen3 Prius cabs here have been failing prematurely (see other threads).

With hindsight I think the gen3 Prius is too highly strung to be a commercial workhorse. The op might have been better getting an older gen2 Prius as those are much hardier.