rrandol5

Hi all-

2001 Honda Odyssey EX
Automatic
~142,000

I'm just going to tell the whole store and hopefully y'all will have some advice for me. I just inherited my mom's 2001 Odyssey. She passed away on Thanksgiving but I had been driving in for about a month prior since my Civic is having issues (different issue for a different thread). She got this van in 2013 and the only thing it's had go wrong since she got it was the engine coolant temperature sensor. It's never shifted hard, never slipped, nothing.

The day before I am supposed to drive this van from TN to take 5 of my family members AND my mother's remains to KY, I take it into one of the local Honda dealerships for an oil change and a "Complimentary Holiday Road Trip Inspection." They change the oil, come out and tell me I'm going to need brakes soon and a few other minor things, but that it's definitely ready for a road trip.
Later that night we had a memorial service for my mother. I leave there to go home (about 30 miles away), drive about a mile down the road, stop at a traffic light, but then when I try to take off it doesn't go (Feels like if you were driving a stick and you didn't let off the clutch). It does eventually go, but now it's shifting hard and feels like it is slipping into neutral. If you turn it off and back on, it goes for a while then seems to slip into neutral again. We drive it home this way (took about 2 hours) but we do make it back. While this fun is going on, the D4 light is flashing, the TCS light is flashing, and the CEL has come on.

The next day I had to reschedule my mother's funeral because of this issue but we did finally get that settled. The day after that, I check the code and get P0720. That's it, no other codes. I do some research then replace the Countershaft Speed Sensor. Clear the code (with the code reader) no change and the code comes back. Transmission still won't pull much, if at all. Took the new sensor off (since it was $98) and put the old one back on.

By this time the Honda dealership has made their little follow up call to ask how my service was. I tell them ALL about it. They are apologetic and offer to look at the van free of charge if I can get it to them (about 40 miles away). After considerable hassle, I get the van up there and drop it off. They are fully aware at this point that they will NOT be able to drive it into the garage but I wrote it on the key drop envelope just to be on the safe side. The next afternoon they call and say "Well it's going to need a new transmission; that'll be $4800" I laugh and tell them I will have a tow truck pick it up. I go up there to have it towed and I notice the van is in the same spot where I left it. I get the keys and the paperwork from them and ask what diagnostic steps they took to determine it needed a new transmission. They say "Oh well we couldn't drive it back so we checked the code. It's P0720."
So from just that code alone, they have decided it needs a new transmission. So these are my questions,
*How likely is it that this dealership is trying to screw me?
*Given that the transmissions in these vans have a horrible reputation, how likely is it that I will actually need a new transmission?
*If it is likely something else (which is what I have gathered from my research, fingers crossed) how do I go about determining what the issue actually is? I am pretty good with cars but I don't know much about automatic transmissions and any legitimate advice would be appreciated.

rrandol5

No one? I'm about to have it towed to a transmission shop so I will update this thread once I discover what the issue is.

civic-steve-94

Sorry to say, but I'm a mechanic at a private shop in California and we see these die all the time, for no apparent reason. We don't rip them apart we just replace them though. We go through jaspers, they reman the trannies and make you install a second trans cooler. They have a 3 year 100,000 mile warranty too. But that is worst case I hope yours is a simple fix. Good luck

slowcivic2k

P0720 is an electrical fault of the countershaft speed sensor circuit. This code is caused by a defective sensor, or broken/damaged wires running to/from the PCM. If you replaced this sensor with a known good part, and the code recurs, you have wiring or connector damage.

Unfortunately, after you fix P0720, you will most likely trigger a slippage DTC. Both speed sensors need to work to trigger it.

The slippage is terminal on the B7TA, and is quite common. 2nd and 3rd gear are the most notorious for slipping. I would start by making sure the unit is full of fluid before anything else, and identifying any transmission leaks.

You will most likely need (from experience) a full steel/clutch rebuild kit, a replacement torque converter, and possibly bearings and an oil pump. If you are not mechanically inclined, a replacement is your best option. The parts to do this yourself should cost around $800 all said and done, and about $100 in tools (clutch spring tool, axle nut sockets, 5-50lb torque wrench, etc).

It is my personal opinion as a rebuilder, that you should fix the problems you have with the current unit, rather than risk installing an improperly repaired "refurbished" unit. A brand new unit is really the only way to go if you do find a replacement.

The DTC P0720 does not condemn the transmission, but the slip code that will occur after that code is fixed will.