[masonc]

Hello Piloteers! I've been browsing this forum for a couple of months but have finally joined.

I bought a 2003 Honda Pilot in October (170k miles). It had known transmission issues and the guy sold it to me as "salvage". At the time, it barely drove forward and would not go in reverse. The codes I got immediately off the OBD2 reader were P0730 and P0780. I researched this forum and YouTube heavily and started performing various tweaks. I started with Something to check on higher mileage Pilot transmissions which showed the clutch solenoid (Control C) and the A/B solenoid getting dirty.

I started with the low-hanging fruit - the clutch solenoid. I pulled it off and found debris on the screen. I cleaned it off and put it back in. The gasket was very rough looking though and started leaking, so I ended up ordering a new solenoid altogether (I couldn't find a gasket on its own). With that replaced, I also performed a drain and fill with 4 quarts of DW1. The fluid was pretty bad looking and the drain plug had a bunch of gunk on it as well.

After that, the car appeared to be driving a bit better - I could get it in reverse and it was somewhat drivable forward. First to second is pretty smooth, but when it goes from second to third, there is a slight delay and then it jolts into gear. Third to fourth is smooth. The other issue I have found is that at high speeds, usually going uphill, the car will appear to shift down to first (or something - the revs go WAY up) before shifting into what I assume is 5th. This only appears uphill and accelerating.

The next thing I worked on was cleaning out the A/B. I noticed some debris on those screens, but it wasn't nearly as bad as C. Unfortunately, I snapped off one of the connectors trying to get it back in - so I had to replace that one as well. I did one more drain and fill of DW1 when I replaced it - the fluid still seemed pretty dirty (and more gunk on the drain plug).

Now the interesting part - I have noticed that if I drive it for a while, park it, return within 20 minutes and start it again, it shifts and slips horribly. Once I started letting the engine run for a couple of minutes after parking before shutting it off, this stopped. I figured heat had something to do with this after reading this post. It has gotten quite cold here and the car is shifting pretty much perfectly now. I have bought a new transmission filter, but have yet to install it. I want to know if I'm making the right decision to change it or not.

I have performed various additional maintenance like fresh oil and new spark plugs. But the issue remains - if the car gets warm enough, shifting between 2/3 is noticeable and the hard downshift going up hills at high speeds happens occasionally. Should I put the effort in to change the transmission filter, or would this be futile? Any other suggestions would be appreciated. I was prepared to buy a new transmission if needed, but I'd still like to try anything else to repair this one first.

 

[royalbiggster]

You're going to have to do the drain/refill a few more times. Especially if you are driving a good distance between drain/fill. It is short distance driving, basically getting up to operating temp through driving around between drain/fill. The more you drive, the more it mixes. They hold roughly 9 quarts, but you are only drain/fill roughly 3. With the drain plug magnet picking up debris, you're probably going to want to wait until you have clean fluid before installing the filter, otherwise you will just gunk up the new filter. You're going to want to keep checking on the metal screens as well. Check all of the solenoids and switches in this diagram. Bench test them as well.

 

[royalbiggster]

How are you checking the Transmission fluid? You want to check it at operating temperature on level ground between 60-90 seconds, in that 30 second window. Checking it cold will overfill it, and cause damage to the transmission through too much pressure, and you will most likely be forced to replace the transmission if that happens. Anywhere between the lines is good. 3/4 ideally.

 

[STMech]

Sounds like dirty fluid and internal wear are your problems. Consider using Valvoline Maxlife ATF in a few more drain and fills. Maxlife has seal conditioner to help the worn clutch seals work better. Some folks recommend AT-205 additive to really jump start the process. I would stick to Maxlife and give it a chance. Save the AT-205 as a last chance before transmission replacement.

Yes, replace the filter!

 

[masonc]

Hey @royalbiggster. I am aiming for 100 miles between the drain and fills - this is not a primary vehicle for obvious reasons. When I check the fluid, I get the car warm by running for about 10-15 minutes. EDIT: I then turn off the ignition and wait the recommended 30 seconds. When I checked it last, it was at about the 3/4 mark on the dipstick. However, the temp of it running ~15 minutes (halfway on the C/F dial) may not be the temp the car is getting to when it starts to slip. But again, no matter how much I drive it right now in this 10-degree weather, I cannot get it to slip.

This is what the fluid looked like after the first drain and fill (and about 65 miles). I don't have a picture of what the fluid looked like at the beginning, but I imagine much worse.

Do you also have any more specific recommendations on solenoids/switches to check? That sure are a lot of them so I'd rather avoid any that would be irrelevant (since they're a pain to get to).

@STMech - I've seen mixed feelings about Valvoline Maxlife on here, but I'm to the point where there's not much to lose.

 

[royalbiggster]

You cleaned the screens and replaced the clutch solenoids labeled in the diagram:
-a/t clutch pressure control solenoid A/B
-a/t clutch pressure control solenoid C
That is a great start. Those screens may get clogged again.
Shift solenoid valve a and c get rusted and if they are clogged, can create issues. I would take them off, and bench test them. Might have to remove, or at least loosen the starter to get to valve A. Clean them out, and make sure they have a healthy click when you apply 12v to them. You don't want a weak click, it should give you a solid click. Give them several clicks, because sometimes they stick, and will work intermittently.
When you are done driving and it has had time to fully warm up, and the fans come on is when I would check the fluid level. I use a timer and will clean the dip stick, and at 60 seconds (1 minute) I will check the fluid level. You only have 30 seconds to get an accurate measurement. So between 60-90 seconds. Check it twice.

 

[WiiMaster]

Before MaxLife, I would actually try some LubeGard Red. The stuff can often work magic.

 

[masonc]

You cleaned the screens and replaced the clutch solenoids labeled in the diagram:
-a/t clutch pressure control solenoid A/B
-a/t clutch pressure control solenoid C
That is a great start. Those screens may get clogged again.
Shift solenoid valve a and c get rusted and if they are clogged, can create issues. I would take them off, and bench test them. Might have to remove, or at least loosen the starter to get to valve A. Clean them out, and make sure they have a healthy click when you apply 12v to them. You don't want a weak click, it should give you a solid click. Give them several clicks, because sometimes they stick, and will work intermittently.
When you are done driving and it has had time to fully warm up, and the fans come on is when I would check the fluid level. I use a timer and will clean the dip stick, and at 60 seconds (1 minute) I will check the fluid level. You only have 30 seconds to get an accurate measurement. So between 60-90 seconds. Check it twice.

I stopped at Autozone to get a new multimeter and some cables for testing. I will check the current levels of ATF (to see where I got it last) and then do another drain and fill tonight. I'll be in a garage much more level than the place I was working on it before. I will see about the valve A & C tonight - need to see if I can get to them without taking too much apart. I had a rough time getting to the clutch A/B and those appear to be right next to it.

I have 4qts left of Honda DW1 - enough for tonight - if I was to switch to Valvoline or another as suggested, should I do any more DW1 drain/fills or should I just go straight to Valvoline? After tonight I will be at 3 drain/fills with DW1. Unclear if the previous owners ever changed it (highly unlikely)

 

[masonc]

Before MaxLife, I would actually try some LubeGard Red. The stuff can often work magic.

In regard to this - I think heat is playing a factor here. I've read that Valvoline may handle the heat better. The heat may be caused by the filter that is likely clogged though, so that may not remain an issue if I replace that.

 

[WiiMaster]

In regard to this - I think heat is playing a factor here. I've read that Valvoline may handle the heat better. The heat may be caused by the filter that is likely clogged though, so that may not remain an issue if I replace that.

Perhaps so. Whatever you choose, I'd strongly suggest adding some Lubegard Red. You've got nothing to lose and I've seen it revitalize some very old, broken down ATs. A 10oz bottle is $17 at AutoZone, and you need one ounce per every quart of fluid capacity in the transmission.

 

[masonc]

Perhaps so. Whatever you choose, I'd strongly suggest adding some Lubegard Red. You've got nothing to lose and I've seen it revitalize some very old, broken down ATs. A 10oz bottle is $17 at AutoZone, and you need one ounce per every quart of fluid capacity in the transmission.

Ok so it won't react poorly with Valvoline - I won't have to do (more) drain and fills to flush it out if I make the switch. I might try that tonight and see if it helps.

Edit: I see that the working mechanism of Lubegard is by reducing heat - so it definitely can't hurt.

 

[STMech]

Your transmission has been neglected; the ATF is full of debris, and the clutch seals are worn due to high mileage.

IMO, the first thing to do is to repeat drain and fill until the fluid is clean. If you want to use Honda DW-1, that’s fine.

I suggested Valvoline Maxlife ATF because of the seal conditioner. Use the fluid that you like, just repeat until clean.

If the internal clutch seals are worn, and it sounds like it, then clean fluid is not going to fix it. A seal conditioner might help. I don’t think that there is any magic in a bottle for a worn out transmission. You might be able to get a couple of thousand more miles.

And maybe you get lucky and your transmission starts to work as designed.

All the best.

 

[road2cycle]

One thing that hasn’t been mentioned is to read the Honda specific transmission codes. There is a method to have the main (but not sub-code) blink on the dash. One common part which fails on these trannies is the 3rd and 4th gear pressure switches. But you don’t mention seeing a flashing D on the dash so the code for that isn’t being thrown. If you end up replacing the switches bite the bullet and get OEM . . . or end up doing the job twice using OEM the second time.

 

[plplplpl]

Sounds like dirty fluid and internal wear are your problems. Consider using Valvoline Maxlife ATF in a few more drain and fills. Maxlife has seal conditioner to help the worn clutch seals work better. Some folks recommend AT-205 additive to really jump start the process. I would stick to Maxlife and give it a chance. Save the AT-205 as a last chance before transmission replacement.

Yes, replace the filter!

Yes! MaxLife drain & fills until clean, then AT-205 on your last fill, so it has the usual statutory 5 hours of running time to do its thing.

should I just go straight to Valvoline?

Yes.

Perhaps so. Whatever you choose, I'd strongly suggest adding some Lubegard Red. You've got nothing to lose and I've seen it revitalize some very old, broken down ATs. A 10oz bottle is $17 at AutoZone, and you need one ounce per every quart of fluid capacity in the transmission.

I'd be curious to know how that Lubegard Red works out. I'm all for a cure in a bottle if it actually works.

One thing that hasn’t been mentioned is to read the Honda specific transmission codes. There is a method to have the main (but not sub-code) blink on the dash. One common part which fails on these trannies is the 3rd and 4th gear pressure switches. But you don’t mention seeing a flashing D on the dash so the code for that isn’t being thrown. If you end up replacing the switches bite the bullet and get OEM . . . or end up doing the job twice using OEM the second time.

I was going to mention those 3rd and 4th transmission pressure switches (yes, OEM only). Swapping them out has often done the trick, but it depends on the crux of the cause. Anyway, they aren't all that hard to replace in terms of accessibility, so you can try that as your hail Mary before the nuclear option of replacing the transmission.

The OBD2 scan tool that also reads Honda-specific codes I have and which is among the least expensive that can do that, is the Foxwell NT630 Plus.

https://www.aliexpress.com/item/32837298303.html?spm=a2g0o.productlist.0.0.73d9663e4ZphMn&algo_pvid=1c14bd50-5459-4608-800f-9ff5b8579bdf&algo_exp_id=1c14bd50-5459-4608-800f-9ff5b8579bdf-0&pdp_ext_f=%7B%22sku_id%22%3A%2212000018594876589%22%7D&pdp_npi=2%40dis%21CAD%21218.49%21133.28%21%21%21%21%21%40210318bb16721922347065301ec715%2112000018594876589%21sea&curPageLogUid=bHpiHe1ksUnz

 

[masonc]

Ok - a few things from tonight's work

Checked current fluid levels - too high. Slightly above the top dot. When I checked it last, the car was parked on a not-so-level street (Note that this was only overfilled for about ~100 low speed in-town miles).

Drain & Filled - Used the last of my DW1 - about 3.5q. Also added Lubegard Red - though it may have been silly to add it now since I will be draining/filling again. I bought some Valvoline Maxlife - will drain/fill again relatively soon.

Fluid is still dark - using a different camera in a different light though so colors are off

Drain bolt has gunk, but much less than previous times

Looked at solenoid valves A/C - It's safe to say they have seen much better days. I did not feel like working on these tonight after seeing this - I will revisit when I have more time to allocate.

Checked fluid levels x2 - I have the fluids exactly half way between fill lines - I figure I'll need to add more when I pull solenoids off and such.

Driving it - I'm always gentle driving after anything transmission-related. At first it seemed pretty smooth, but a few miles in and I was hit with heavily delayed third gear shifting among other clunkiness. I noticed an instance of delay in 2-3 shift on my way to the store this morning - so I'm thinking the temps being back to normal is bringing back all the tranny issues. The sub-zero temps made it drive like a dream for a bit.

@STMech - Yes, unfortunately, a lot of maintenance on the car was neglected - as seen in the photos. However, it's otherwise mechanically sound and the interior is perfect so either fixing or replacing this transmission will yield me a great car.

@road2cycle - I have seen the flashing D. I shortened my first post since I already have too long of a history with the car. When I first got it and it was really screwed up - getting past 25-30MPH (unsure of gear - 3rd/4th) would cause horrible clunking/revving and then the D would start flashing until you parked it and restarted it. I haven't seen that since cleaning solenoids / 1st drain & fill - but I've seen it. I've seen talk of those pressure switches, but since the flashing D has not happened in a while, I've moved on to other possible faults.

@plplplpl - I've used up my remaining DW1, I don't plan on keeping it in for long, but then yes - Maxlife is the plan. Might put it in tomorrow. It will be hard to determine if Lubegard Red helps given all the other variables - but I'm keeping the whole process documented and we will find out by the end. For the OBD2 reader - I may look into that. I bought the cheapest one on Amazon (before I realized there were manufacturer-specific codes ).

I'm glad I have joined this community versus just looking in - I haven't seen a forum this lively since the early 2010s! Thank you all!

 

[plplplpl]

However, it's otherwise mechanically sound and the interior is perfect so either fixing or replacing this transmission will yield me a great car.

Wholeheartedly

I'm glad I have joined this community versus just looking in - I haven't seen a forum this lively since the early 2010s! Thank you all!

 

[WiiMaster]

I'd be curious to know how that Lubegard Red works out. I'm all for a cure in a bottle if it actually works.

It's good stuff. Can't fix everything but there are plenty of success stories on several other forums, and I know people who add it even to their perfectly fine transmissions to keep them running smoothly.

There was even one case on an Accord that I believe had the original fluid all the way to 300k or something crazy like that. A 3x drain and fill + Lubegard Red got it shifting crisply again.

 

[road2cycle]

Keep us posted on what you discover through the experiments/testing. We’re always rooting for someone to resolve a tranny issue without having to do a rebuild. @andywatson put up a valiant (and well documented) effort on her Pilot’s tranny before having to go with a rebuild. If you haven’t seen her posts you should check them out and perhaps find some things you haven’t tried yet.

 

[royalbiggster]

03 Pilot. I wonder if you got the oil cooler done from the Dealer. Do you have a metal line attached to the fill plug? If you do, it was done, if you don't it was never done. You will want to get one installed. I wonder if they still do it for free at this point. I would hit up each dealer until you find one that will.

 

[andywatson]

Keep us posted on what you discover through the experiments/testing. We’re always rooting for someone to resolve a tranny issue without having to do a rebuild. @andywatson put up a valiant (and well documented) effort on her Pilot’s tranny before having to go with a rebuild. If you haven’t seen her posts you should check them out and perhaps find some things you haven’t tried yet.

Yep, OP's description of the problem sounds just like my issue that started last winter. Transmission does fine when things are cold, but when it warms up, it starts to slip when shifting from 2nd to 3rd. I replaced all the solenoid valves, did lots of drain-and-fills, and each time there was more and more metal shavings on the drain plug magnet and in the screens of the solenoid valves. I ordered the rebuilt transmission yesterday, hopefully I'll have it installed next week and I'll update everyone on how it goes.

For anyone wanting to see the full backstory, my original 2 posts are here: Transmission slipping? and transmission problems getting worse, next steps?