[Lochinvar]

I have a 98 CR-V auto, and it started doing something wierd today. I was crawling in traffic, so I'd been in 1st gear for a while, and suddenly the transmission would seem to go into neutral. I tried shifting into 1st and 2nd manually, and it made no difference. When I stopped and restarted the engine, however, the tranny returned to normal right away. As I continued driving, I found that it would happen in any gear, at any speed. The transmission would be fine for a period, then suddenly go to neutral. When I stop the engine, wait 3 seconds, and restart, the transmission would behave like normal, until in decided to go into neutral.

Sound familiar? I've seen 3 posts of this problem is here just today!

Here's what happens:

The 1st Gen CR-V Automatic transmission has an internal all filter and it gets clogged over time. Stuff gets sucked in, blocks the filter, transmission loses oil pressure, clutches disengage. When you stop the engine, the transmission oil pump stops too, the junk falls out, unclogging the filter, and upon restarting, the transmission works normally again, until the junk clogs the filter.

The problem is that you have to remove and disassemble the transmission to replace the Tranny's oil filter. Given that I don't have a spare 2k to spend on a transmission rebuild, I didn't want to do that.

So here's how I fixed it:

CR-V transmissions have oil pressure inspection ports. You pull a plug out, and install an oil pressure gauge, then you operate the engine and transmission and check the oil pressure. There is one port for each of the 5 clutches, and one for the main pressure line. Checking the hydraulic control chart in my service manual, I found the Line port is right after the oil pump, which is right after the filter, and the Line port is right on the top of the transmission, by the lock-up control solenoids.

I figured I could reverse-flush the oil filter by blowing compressed air into the Line port, and I was right!

My procedure is this:
Put drain pan under vehicle.
Charge air compressor.
Start car, and run through all gears to pressurize hydraulic shift control system.
Stop engine.
Drain transmission, and temporarily reinstall drain plug.
Remove transmission dipstick.
Remove plug from Line inspection port.
Use small blow gun with pointed rubber tip to blow compressed air into the line inspection port until you hear air bubbling up through fluid in transmission for a moment.
Drain transmission again.
Use tube brush or similar to try to remove as much junk as you can from transmission housing, and from under transmission oil filter (just inside drain port, and to the right).
Reinstall drain plug with new washer.
Refill transmission (you'll need to use about 4.25 quarts used of 3).
Start engine, run through all gears, stop engine, and recheck fluid level.

I did this last week and my transmission was about 95% recovered! My only problem was that 1st gear would drop out, and re-engage sometimes when I was in M1 to descend a hill, or starting from a stop after the transmission was warmed up. I did my reverse-flush again yesterday, and my tranny seems to be 100% fixed!

I'll post an update later if you want to find out how it holds up.

 

[Tigris99]

Good job on coming up with a temporary fix though. Congrats. NICE WRITE UP TOO

Sad to say though, it's not completely fixed.

It's a great idea for those that need a little more time out of their transmission while they get money together to replace it. This is why I never mention back pressure. Plus it's not guaranteed to work as it depends on the damage done. You were smart and got right on top of it instead of driving it constantly with the issues.

First is your transmission is already damaged from lack of pressure.

All that crap you pushed back out of the filter is going to end up right back where it was in not too much time as you only cleared enough area to get fluid flowing again.

Next is the damage to the filter itself. Likely opened up larger spaces in the filter now so debris large enough to cause other issues can get into the pump.

As I said it's a great "quick fix" temporarily. But I would start saving money for a transmission for when yours dies completely.

Sent from my SM-G950U using Tapatalk

 

[Lochinvar]

Not trying to argue, but what damage would be done by lack of pressure? I want the gory details.

I would think the only damage would be wear on the clutches from slipping as they released, but all of the clutches seem to be working fine now.

From what I can tell, the shifting system doesn't care about the oil pressure, it just won't engage the clutches without it, right?

I figure there is going to be more junk in the transmission in the future, but I did get a ton out, and the junk I got out didn't go back in.

Most importantly, have you seen a transmission fixed like this, and how much longer do you think I might have?

 

[Tigris99]

Transmission fluid does more than provide pressure, also lubricates. Clutches are of course the first thing damaged. Right now you have enough pressure to engage them.

First things that are damaged beyond that are the pump and torque converter, which is basically one big pressure drive clutch pack. The pump is the same design as an engine oil pump. So it floats on fluid, likely some scaring in there but nothing major at this point since it works.

The back pressure could have damaged seals as well, there are some lip seals that don't like reversed pressures. If they haven't gotten too hard or hot yet then be ok for a while I would think.

Biggest issue is going to be the clutches. They would have gotten hot due to slipping without lubrication. So they will wear must faster now.

Never tested how long it lasts doing that and it can vary greatly. Haven't done it on a CRV but have on a couple Accords. First one they had it a month till they got their taxes and traded it off. Second one they got a couple months out of but was in for rebuild before it died. 2 sets of clutches we're pretty smoked and torque converter showed signs of having gotten rather hot. Not to mention all the crap still in the valve body and solenoid screens. Probably a good idea to pull solenoids and check the screens too, buy you a bit more time possibly.

Just like an engine, transmission don't like being starved for oil but are even less tolerant to it be it low level or plugged filter.

I wouldn't do any big road trips but if you want to keep it start getting prices on a transmission so you can save for it. Then report back if it has issues or dies before then. We are curious (myself and the shop owner who is an almost 40yr transmission guy) how much this actually helps. We just won't experiment with a customer's vehicle and I'm not going to do it to mine till I build another trans for it.

Good luck and keep us posted.

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[Lochinvar]

Update: Still running And driving!

I said I'd post an update later, and I am. When I got my transmission working again my car was at 182,844 miles, and it still drives fine almost 5000 miles later (187,550, as of today).

Now for the details...
You might notice that is a lot of miles for only a couple of months. It comes from a couple of things. One is that I live a long way from where I work, so my commutes are long, but also I deliver food for DoorDash after work most nights. It is a bit stressful on me, and definitely on the car, but I work in a bike shop, and there's no money in the bicycle industry for mechanics' salaries or anything else really, so I'm usually strapped for cash. Even so, my driving is still about 50% highway, 50% city driving. I just drive a lot.

A second thing to be aware of is that my driving is mellow, like very mellow. I tend to accelerate slowly from stops, take my foot of the gas as early as I can in most circumstances, and I usually only speed by accident. I learned to do this for fuel economy, but I also do it for safety, because I like to be mellow as much as possible, and I hate using my brakes. The result is that what most people think of as babying their transmission, is actually my normal driving style.

It would make sense then that my tranny might last unnaturally long, even considering my high-mileage nature, but the part I wish I didn't have to say is that it hasn't been completely trouble-free.

My only problem since getting it to work again has been slippage in 1st gear. I have actually narrowed the problem down to what's called a 1-way-clutch.

This is a particular strange feature in CR-V transmissions. It is a sgrag-type clutch that functions much like a bicycle freewheel. When the engine wants to move faster than the wheels, it engages and moves the car. When the wheels want to move faster than the engine, it slips and allows the car to move faster. The idea is that the car then leaves 1st gear engaged the entire time you're driving forward, and it just engages the other gears on top of first. When you come to a stop then, and suddenly hit the gas to accelerate, first is already engaged and ready to move the car.

When you manually engage first, however, a secondary first gear mechanism which uses an extra regular multi-plate clutch is used, which gives drive and engine-braking.

The first gear slippage has not yet been a serious problem because of a few of things. One is that it has only really slipped a little, and by the time in does, the car is ready for second gear. Another is that the 1-way-clutch is engaged by torque, so if it does start slipping, I can just press the gas harder for more engagement. For this reason, someone else might have much less trouble with it than me because of how light on the gas I am. The third reason this is a limited problem is that I can just shift through the gears manually, and then the 1-way-clutch isn't used at all.

My solution to this:
The first thing I noticed about it is that the slippage only happens when the transmission is warmed up. The biggest difference between a cold and hot transmission is the fluid viscosity, which gets thinner when hot. I happened to have a bottle of Lucas Transmission Fix on hand, and that stuff is thick, like chocolate syrup thick, so I was reluctant to try using it because I didn't want to mess anything up, but after noticing the temperature-related symptoms, I tried it. I only carefully put it in in little amounts, noting the changes as I did, but it seemed to help a lot. Now the problem only seems to be there if I'm feather-light on the gas. I seemed to get maximum benefit after putting about 2/3 of a bottle in (about 16 ounces).

Something to take into account though, is that I did log a number of miles diagnosing the car while it was broken, trying to figure out how to fix it. I don't know exactly how many, but it did drop into neutral a bunch of times while I was trying to find my cure. The result is that there's probably a lot more wear in there that there would be if I had known how to fix it in the first place.

Before you all start calling me crazy, I do have a shop I am planning to go to for a rebuild if/when it gets bad enough that I don't want to drive it, but I am going to keep going with it as far as I can out of curiosity. My innate problem solving nature has to know what happens as I go along. I also think it will be helpful to order CR-V owners to know how far they can go if/when they have these problems.

That said, my love for the car, combined with my uncontrollable info to diagnose stuff, does drive me freaking nuts when my car isn't nearly perfect, so I'm almost certainly going to give up and have it rebuilt long before it's becomes completely unusable.

At this point though, I'm still driving Big Green. I'm still enjoying it. My car has not left me stranded yet, not even when the problems were at their worst, and I certainly don't expect it to now.

I'll again post future updates as I keep driving.

 

[Lochinvar]

I think I jinxed myself with my last update. I started having a problem right after I posted it.

My transmission started doing a few weird things, and I can post more details if anyone wants to know, but I tracked it down to a bad shift solenoid. Seems easy, I thought, so I got a used one and put it on (the shift solenoids bolt right on to the right side of the transmission hosting).

The transmission immediately returned to normal. Everything worked great...

... For one week. Then, it happened again. I figured I had just bought a bad one, so I replaced it again. The second replacement also only lasted a week. Now I'm at a loss to know why it is happening. The shift solenoids definitely stop functioning, and that is definitely the cause of my shifting problems, but why is the transmission suddenly just killing shift solenoids, and why do they keep failing so fast?

If anybody has any ideas, please let me know.

 

[Lochinvar]

I guess this is going to be my final update on this thread.

I got tired of replacing solenoids, and had a shop rebuild it. It only cost me $1400 (1250 for the rebuild, 150 to extend the warranty coverage from 1 year to 2 years).

I talked to the guys at the shop for a while about it, and they couldn't really give me an answer about why the tranny was just killing solenoids. There were other issues inside (worn out clutches, 1 damaged drum, etc.) so I'm glad I had it done, but it still bugs me that I don't know what was happening! I want to know what it was that suddenly started taking out solenoid after solenoid!

Anyway, it's been a couple of months now and Big Green is running and driving great. I've had no issues, no fluid leaks or other problems.

If any of you are in the Orange Country/LA/Inland Empire area, I highly recommend the shop I went to. They're called California Transmission, and located right off Mountain Ave between I-10 and CA-60 in Ontario.

The guys there are very nice, helpful, knowledgeable, generous with their time, and They get work done pretty quick. I left BG to be there for a week, and they had it done in 3 days IIRC.

I still have a couple of the dead solenoids, and I'm tempted to take a dremel tool and cut them open. If I do that, I'll post pics for anyone else who might be curious.

Cheers.