Honda CVT rebuild: bad idea?

Hey all, I may have destroyed the transmission in my wife's 2005 Civic hybrid. You can find these cars on craigslist (for cheap!) all day long, but most suffer from a similar illness - having them fixed outside of warranty ain't cheap, and it was a common point of failure.

However, a rebuild kit on eBay is only $400! I haven't bought the shop manual yet, but does anyone have experience with this, or secondhand knowledge of how much of a bear this job is? Waste of time from the beginning? Asking for a friend. Thanks!

Watching with interest.. not because I have any thing with a CVT, but because they fascinate me from an engineering standpoint..

The trans guy we work with said CVTs are the simplest things ever, and after going through a couple, he can't understand why some trans shops won't touch them.

Note: The last time I was over at their building, he was rebuilding a 2-speed from an early 60s Falcon.

In reply to Knurled:

That would have been the "Fordomatic."

I have been trained to do the Chrysler (Nissan) trans and I have to say there is not much to them. The special tools might be the only thing holding you back.

Do yours with success, buy all similar cars with bad transmissions, $400 rebuild, profit!

That's what I'm thinking, Patrick! Er, I'm sure that's what my friend is thinking.

Full disclosure, I've never rebuilt a transmission and no longer have 24 hour access to a machine shop, so the special tools are certainly of primary concern. I'm thinking I'll buy the big shop manual first, but how special do these tools get?

Does make you wonder who is buying these rebuild kits, doesn't it? My Honda dealer, perhaps?

I have made any special rebuild tools with scrap for rebuilding transmissions. The manuals usually have images of the tools, or you could image search the part number

jsymonds wrote: Does make you wonder who is buying these rebuild kits, doesn't it? My Honda dealer, perhaps?

I'm not saying that we find it easier sometimes to buy parts on eBay or Amazon...

Tools, actually, mostly. But, if you need a replacement widget for a '82 Framus and none of the usual suspects are willing to help you out, you go to where you can.

I still remember the time we called a local boneyard looking for a power rack and pinion for a Chevette and they hung up on us, because they thought it was a prank call.

I've been vaguely planning to buy a broken CVT honda hybrid to rebuild the trans for years now. One problem i see occasionally is that some of them actually put holes in the case! I have a customer who had me looking for a used unit for their civic hybrid as theirs put a hole in the case. The only one cheap enough to call so far also had a hole in the case. Any word on that?

You're WR. What's our motto?

https://www.youtube.com/embed/uL0ROeZw7wA

If eBay has taught me one thing it's that you should always buy genuine Honda parts. Lest you want failure in 2.5mi.

In reply to mck1117:

Ignorance is bliss! Most special trans tools I've seen look dead simple to make with a mill, lathe, and welder. Step 1: acquire the aforementioned. Maybe I can even replace the lathe with a rotary table!

Meanwhile, I expect my wife is wondering how buying a mill is supposed to help her get to work...

In reply to Trackmouse:

I have a fair number of off-brand parts on the cars at this point, and I can't fault your logic, though usually it ends up alright. For transmission parts I can certainly see the motivation to play it safe.

I had kind of assumed these eBay parts are made by the same manufacturer, only binned as lower-quality units (for whatever reason). Then that company, rather than throw them out, they sell them cheaper and without the seal of approval. It seems like it would be crazy for some third party to come along and decide "hey, you know I bet we could make money designing and fabricating our own belts for civic hybrid CVTs!"

That's not an argument against your point, obviously. But I guess it depends how it's worse? On the bright side, I'll be way faster at the repair the second time!

Update for the curious: after returning from a nice vacation in Michigan I winched the Civic up my driveway into the garage and changed the trans fluid again. The troubleshooting guide gave me a glimmer of hope that if I did not find metal shavings, the transmission problem might be intermittent. Well, the fluid smelled a little toasty, but was free of metal! Hooray. At first I thought a few flecks of dirt had entered into my fluid catching setup, but on closer inspection they look suspiciously like tiny (1-2 mm) flakes of clutch material. Only half a dozen or so of them, but...that's not great.

Once I had it on level ground I also observed that the car does, in fact, move under its own power - it's just totally gutless in forward or reverse gear, slipping so badly I can't climb a shallow driveway. I pulled CEL codes and got a P0700 "Transmission Control System (MIL Request)" and a P0796 "Pressure Control Solenoid "C" Performance or Stuck off.

Now, I have two theories and really can't choose between them on the evidence I have.

Theory the first: that solenoid is responsible for the oil pressure which allows the CVT belt to grab(?), and was clogged by a little piece of clutch or something. It's a relatively external solenoid (according to my mechanic) so that might be the hail-Mary fixit attempt to try first...may be possible without trans removal?

Theory the second: The clutch is toast, allowing no power transfer from the belt, which may be operating.

It could also be both, of course. Once we get my wife back on the road, attacking that solenoid B might be the next thing to try. We'll see! Or I'll get tired of this car and get rid of it :(

One other shred of evidence, not sure if it's related: the second or third times I started it up after changing fluid, the car stalled. I am not sure what causes an automatic to do that. The battery is also nice and dead, preventing me from putting the car in neutral (why, Honda?), so I had to jump the car before I pushed it around, with the engine running to keep the juice flowing. Red herring?

replace that solenoid. I have zero experience, but I bet $5 that fixes it.

So, the definition of that P0796 is "CVT Start Clutch Pressure Control Valve Stuck OFF ". Since that CVT doesn't have a torque converter it has a clutch pack that disengages the engine from the trans so that it doesn't stall when at a stop. When you let your foot off the brake it PWMs that solenoid until you're rolling at whatever idle speed X your min gear ratio is in mph, just like letting the clutch out slowly in a manual. The thing is, i dont think the computer can tell that the solenoid is actually broken, just that the car isn't moving. Here's the diagnosis procedure per AllData:

Clear the DTC with the HDS. Set the parking brake, and block the front wheels securely. Warm up the engine until the engine coolant temperature reaches 176°F (80°C). Fully press the brake pedal, and shift to the D position. While pressing the brake pedal fully, and press the accelerator for 6 - 8 seconds at full throttle. Measure the stall speed rpm in the D position. Does the engine speed exceed 3,500 rpm? YES- Go to step 7. NO- Intermittent failure, the system is OK at this time. 7.Run the engine at 4,000 rpm for 4 seconds, and check that DTC P0796 recurs. Is DTC P0796 indicated? YES- CVT start clutch pressure control valve may be stuck OFF. Replace the CVT start clutch pressure control valve, then go to step 8. NO- Intermittent failure, the system is OK at this time. Clear the DTC with the HDS. 8.Test-drive the vehicle for several minutes under the same conditions as those indicated by the freeze data. Check that DTC P0796 recurs. Is DTC P0796 indicated? YES- Replace the transmission assembly.

So, basically the diag is 'can you brake-stall the vehicle past 3500 rpm? ok the start clutch isn't working. Replace the solenoid and if that doesn't fix it replace the whole transmission because the start clutch is burnt up and we don't do on-site rebuilds in our dealerships'. That suggests to me that the computer can't actually tell that the solenoid is bad, just that the car isn't moving.

Since you have clutch material in your fluid and the car still attempts to move somewhat, i'm guessing the start clutch either is leaking or worn out and it's not actually a solenoid problem. Even a mostly clogged solenoid would still apply the clutch pack as long as it was able to flow faster than the circuit leaked, it would just have very slow initial engagement. Of course, if you applied power during that slow engagement.. you'd burn up the clutch pack. Either way i think the clutch pack itself has failed at this point which means rebuild.

Thanks, Vigo, for the detailed response. I liked Robbie's better, though! :(