To remove the valve body on transmission fluid change, or not?
 

Hi folks. With the last of the parts getting here today, I'm planning on doing a transmission filter and fluid change this weekend. I'm going to be doing it "Reverend Sam style" on the floor with Jack Stands. While ordering the parts I got the valve adaptor in the kit so I figured I might as well order the valve body seals as well. In reading up and watching a few videos, I see most people don't remove the valve body, and replace these parts. Should I? And if I do, is there any other gotchas I should be aware of with removing the valve body and reinstalling it? I have the parts, and I'm down there anyway, but part of me doesn't want to disturb any more then I need to. Especially since I don't have a lift, and will be doing this on my back with the car a few inches above my head.

The reason for me moving this job up in the priority list is that while I've had the "clunk" into reverse since I got the car, I had a new issue show up. After going on my first couple of longer drives (over an hour), and likely getting the transmission nice and hot, I've gotten some concerning gear box error codes when pulling on to an onramp and getting into 5th or 6h gear, that put the car into some limp modes. I've checked and the wheel bearings seem solid (no wheel movement when jacked up and pushing and pulling), and I've cleaned the wheel sensors, and they seem fine now. So, I figure it's time to crack open the transmission pan, and A, see if I see something more disturbing, or hopefully B, some new fluid and filter fixes the issue. Pan looks original and the car has over 80,000 miles on it, so it is about time regardless.

Thanks for any suggestions, or opinions.

I believe you have a 4.2L with the six speed ZF, and haven't read of anyone needing to pull the valve body, nor am I aware of a kit to modify the main pressure valve as was done with the five speed.

So, maybe I'm not understanding locations, because I haven't had the transmission open yet. Yes I do have a 4.2 with the zf 6hp26 transmission.
https://cimg1.ibsrv.net/gimg/www.jag...811d95f653.png

But my understanding or possibly misunderstanding, was that the pump adaptor seal, as well as the long, medium, and 2 short seals were between the valve body and the rest of the transmission. Therefore the valve body would have to be removed to gain access to those locations and replace them. If I don't need to remove the valve body, then this is a no brainer, and I will replace them. If I do... well that is what I was debating, how much extra work is it?, can I cause more harm than good in taking this extra step?, In general is it a good idea, or not. As long as there is not anything obviously wrong, and I don't screw up anything, I'm not planning on replacing the valve body, just possibly removing it, and putting it back in after I replace the seals.

Does this make more sense now?

I’ve done a ZF 5HP24 fluid & filter change and put in Transgo PR valve
 

Go for it. One thing not in Rev. Sam’s video is to check you can open the fill bolt, before draining, otherwise you could be in major trouble.

https://cimg5.ibsrv.net/gimg/www.jag...76b277343.jpeg
Make one of these as it’ll save you a lot of time on the filler bolt as access is bad.

But be very cautious when disturbing the valve body. Even opening it is dangerous as the cover plate is spring loaded.

https://cimg8.ibsrv.net/gimg/www.jag...7c3d64044.jpeg
Don’t do it this way! Enough said!

If you’re removing the lower front valve body, make sure you’ve a spare Torque bit tool as there’s a lot of bolts to undone. Easy to strip the bit. And go slow “ mm by mm wiggle down” as even with all the bolts undone it’s held by an internal guide pin, and don’t prise it apart with a bar as the case is delicate.

Take note of any internal channel inserts and make sure they’re not disturbed. Looking at the Transgo website for their ZF6HP kits, make sure of your orientation (I printed it and wished I put it inside a plastic cover because of all the dripping ATF).

When re-installing, check the side guide pin that links to the gear stick. Make sure the pin is seated

https://cimg9.ibsrv.net/gimg/www.jag...5159e88f8.jpeg


Also when you’ve finished and had run the engine while refilling, you may have to do it again as the Torque Converter holds old ATF. You may need to drain and top up later. Second time round I put in extra 1.5L, and still don’t know why!

Thanks David. I appreciate your confidence. But hopefully I won't even have to crack open the valve body, or even remove the solenoids. I think all I'll have to do is remove the unit as a whole to get access to the seals below. Although I was just watching of a pro transmission guy doing a full rebuild of one on the bench, he made it look easy. I have a feeling it wouldn't be quite that easy for a first timer, where did that check ball go again?

But if this filter change and refill doesn't fix the issue, I guess I may try and have a go at removing it again, and have it checked out. Beats dropping the whole transmission, and having it looked at. At one point he uses a bit of compressed air to check the clutch packs, I wish I could here what he is listening for, since I think that is something I could check while I have the valve body out as well, although I'm not sure it would work if they are not fully drained, and I could see getting a face full of ATF real easy.

The general idea is to go on and replace all the wear items one time during a major maintenance. This is pan/filter, bridge seal, tube seals, connector sleeve, maybe bolts if you have the smaller ones that came in the early transmissions. Once all of that is changed (along with new fluid), you can do one or two more flush/refill procedures later to replace more fluid, but the big job is done. Also, after this procedure, it might be a good time to find the software tools to reset the adaptations (make the solenoid valves re-learn to transition with the new fluid).

The other plan is to first figure out what is wrong with these error codes upfront in case there are problems with the valve body. First thing is to get the codes, and do research. Rear bearings are key of course, but there can be other factors, more than likely external to the trans (brake switch? shifter micro-switches? Speed sensor? Temp sensor? Connector sleeve leak? Pushed pins in the connector on the transmission?). Again, a JLR code reader is necessary here. It is also possible the main problem is located in the valve body. Good news is that it can be pulled without removing the entire transmission. There are solenoid valve kits available out there. They seemingly can be installed at home. Of course you can go for a full valve body rebuild from a reputable company for something more comprehensive. Worst case is to find metal shavings on the pan, magnets then you know something is very wrong with the mechanical parts (clutches, etc.). The trans has to come off for a rebuild/replacement at that point. This seems to be very uncommon for these 6HP26, but there are full rebuild kits available here as well.

Best of luck, keep us posted.

I would view changing out parts in the valve body as a PM procedure the same way I would view poking a snake with a stick, not a good idea unless you really know what you are doing.

Well, I got the project started a few hours ago. I have the pan off, on the ground underneath where it was, and letting everything keep dripping in to it. Overall so far (knock on wood) it's going fairly well. No big surprises, thanks to a bit of reading, and watching, and mostly the advice from here. I still have to remove the mechatronic plug, and sleeve, and of course the valve body itself as well. But I'm taking a bit of a break to watch the rest of the Indy 500, as I let it drip a bit more. The fill plug was as tight as others have said, and working on jack stands does not give much room to get leverage. But finally got it with a regular Allan wrench and a helper pipe. Thanks for the advice to do that first. Broke all of the smaller pan screws free with a 1/4" socket on a small Dewalt impact driver. I only managed to spill a little ATF on myself while removing the pan, luckily it was on an old white t shirt (that's why I wore it). Also, I'm guessing the bad smell means that the fluid is a bit burnt? I haven't had a chance to look at the magnets yet, but will once I pull it out from under the car.

Here is a picture of the tools used.
https://cimg6.ibsrv.net/gimg/www.jag...48e83b534b.png

And the current state.

https://cimg8.ibsrv.net/gimg/www.jag...2afeeb4d30.png


I did take one attempt to unplug the mechatronic plug, and couldn't get real great access. Figured it might be easier after some of the dripping had stopped. Any advice on disconnecting that? Just seems a bit tight up there.

The ATF smell you are experiencing is quite normal. Whether the fluid is 100,000 miles old or 5,000 miles old, Lifeguard 6 always stinks....

Regarding the Mechatronic seal, there is a white plastic lever that you must pull down in order to remove the old seal and install the new seal. Once the new seal is properly seated in place, you push that lever back up. Are you aware of that?

Thanks for the confirmation Jon.

I guess I chose to take my break at the wrong time, so I'm on another one now. After the race the underside was down to about a drip every other second or three. So, I thought I was good to work some more. I got the Mechatronic electric connection pulled (I would not want to do that with a hot exhaust) and finally got the sleeve to disengage from it. Pulled the valve body, dang that thing is heavy when you are holding it off to the side with one arm as you do the last few bolts with your other. I could see that part being much easier with a lift. And then it started flowing again. Not a huge stream, but from one of the now open ports. It took me a while to realize how much was actually coming out, but I finally did and got the oil pan back under it. I guess this is a good thing to get the old ATF out, but it looks like it might be a while. No rush, I'll let it go over night, and finish up tomorrow.

I finally got the pan out from under the car, and took a look. I guess this was done at least once before, even though it still had the smaller headed bolts. There was a silver stamped date in the bottom. I couldn't read the last number, but it was 201? I think it was a 2 or 3, but not sure. I couldn't quite read the casting date either, I can wipe out the last bit of fluid and check that as well. The magnets looked great, nothing on them.

So tomorrow it is just the reverse. I have my fire gloves and inferred thermometer ready to go.

I have this job on my to-do list, has been there for almost two years now.....so John any and all "lessons learned" please post to help me out.

Well, it's done. Or, mostly done. I still have the car on jack stands, and even though I have the tools put away, and the fill nut fully torqued back down. I may double check my level one more time. I'm just not 100% convinced I got the procedure/ amount of fluid right. The biggest thing I learned from this, is it would have been a whole lot easier if you had a helper who was working above and staying mostly clean, while I worked below.

Here is what I did. I started by putting the bridge gasket in, and the tube seals. The tube seals gave me my first worry, I thought they were supposed to be flush, and mine stuck out about a 1/16 of an inch or so. I tried finding info, and the best I got was rewatching the video I posted above, and noticing his stuck out a bit too, I'm guessing about the same. So back under the car, mount up the valve body, this went smooth. Torqued all the screws down to spec, and this also went smooth. Tried to install the new mechatronic sleeve, this did not go smooth. After trying for way longer then I should have, I finally tried the old one, and it went right in. The third party one I had, just wouldn't go (it felt like it was in, but the locking bar wouldn't go back in). So since the old one was still in good shape, I decided to go with that. Lesson learned (as others have said plenty of time, for these parts, go with original, not 3rd party). So now to install the pan, that went fine, torque down all 21 bolts around the edge, that went fine. Time to start filling with fluid.

I used a pump that is meant to mount right on the quart jugs, but it didn't quite fit right, and the straw didn't go all the way to the bottom. I managed to get about 3 quarts in before it started flowing back out. I hand capped it, and went and started the car. Temp was about 18C (measured with an inferred thermometer on the smooth part of the pan where the part number is) , and it took a while to start warming, and it still wouldn't take any more fluid, so I got back up from under the car, and ran it through the right hand side gears and back to park, even though it wasn't at 30c yet. Went back down below, and was able to continue filling. I got about 4 1/2 more quarts (7 1/2 total) in before it started flowing out at 35c. I wasn't sure if I needed to run through the gears one more time, or not. When it got to 37c it was not flowing, and I decided to cap it. The motor was up to temp, and the radiator fan was going. The thick leather gloves I had brought under the car with me were too thick to be useful, and I ended up doing it bare handed (I would not recommend this). I got away without getting burned bad, but I still got a little burned. Got it capped. shut off the car, and waited a few minutes for things to cool down. I was actually surprised how quickly the exhaust cooled down, I was able to work around it in just a couple of minutes. Torqued the fill nut to 25 ft lbs and cleaned up.

I know others have said they have used about the same amount of fluid, but since I had taken the valve body off, and let it sit for a day, I thought I'd need more. So that combined with not getting it all the way to 40, or going through the gears near that temp, has me thinking I should check again. It just was such a messy experience, that I'm still a bit reluctant. If the weather is decent tomorrow (it's not today), I may take it off the stands, take it for a test drive, put it back on the lift, and check then. Heck, that's even one of the procedures I saw.

Understand that to go to the higher temp. is to have less fluid in the transmission. I always start fumbling with replacing the plug at the lower temp.

Good point, and one I had thought about. The only part I wasn't sure on, was running through the gears at the lower temp. I didn't know if I had done it at the recommended 30-35c if it would have sucked more fluid up or not. That's why if the weather is decent tomorrow, I'll take it for a test run, see what happens and possibly throw it back up on the stands, or if it does well, maybe not, and only do that if it keeps giving me warnings. It would be great to do the software reset for the solenoids as well, but I don't think that is an option right now.

Well, I guess I started patting myself on the back a little too early. Went out this morning, and found a bit of a red puddle under the car. Took a while to find the actual drip, since it was going so slow, a drop every 10-15 seconds. I didn't have the time or the work cloths on to get real into it. I cleaned up what I could, and got the oil pan back under the spot. The weird thing is that it doesn't appear to be dripping from anything I worked on. But, I also know that with surface tension this can be deceiving. Here is a picture I took of the drip spot, it all appears to be coming from the freeze plug? on the bottom of the transmission near the bell housing.
https://cimg3.ibsrv.net/gimg/www.jag...ff1df57393.png

To me it looks dry between that and the pan, but like I said I couldn't get real close to see if that was correct, or just an optical allusion. The pan itself was also a bit wet, but it looked like it was just areas I hadn't cleaned good after finishing filling yesterday.

The bad news is, I don't have the time to really deal with this today, and I head out of town for a week tomorrow. So this will just sit and drip for a week. I wish that wasn't the case but such is life.

This plug just pulls out by hand. It is an access hole to the torque converter.

Interesting. OK, I will try and remove later, and see what I see. What would fluid coming out of here typically mean? Would leaving it overfilled do that, or a bad seal at the bridge seal, or is it just a low point and the fluid is filling it from elsewhere? Thanks again.

Too late for this, but this sleeve is a bit tricky to install. There is no twisting allowed, and the new o-rings are a better seal, so harder to fit. They need to be coated in trans fluid for better installation. The next tricky part is to somehow place the new sleeve in a position that allows for the lock to slide back up. I was only able to do that by simultaneously (gently) pushing the (plastic) lock up, AND moving the sleeve around (with whatever play the o-rings had to give). A bit like the steering lock where you have to wiggle the steering wheel a bit as you turn the ignition key. If you were uncomfortable with the shape of the new part, were you able to transfer the new o-rings? Leaks at the sleeve can lead to fluid _within_ the connector and poor connection with the rest of the devices on CAN (it's been reported before).

Best of luck, thanks for sharing, keep us posted.

It likely means nothing good, but maybe this is a way for some extra fluid to somehow escape. I would probably let this go for a bit and see if the leak soon stops. This plug is just a shallow plastic plug (not even rubber), and is a poor seal, so fluid coming out is not a surprise if there is fluid behind it. It is meant to avoid rocks and dust to go in that space, really.

Overfilling Auto transmission is bad news
 

Hopefully your drip is temporary. Maybe your car is on a slope. The first signs of an overfilled ATF transmission sump is erratic shifting when driving. This is due to pressure spikes as the ATF foams in the pick up.

Hopefully you won’t have that but you now know where the drain plug is to empty out a little. Don’t leave it overfilled or you could cause real damage to the ZF unit.