Transmission rebuild
 

I was having trouble with 1st and 2nd flares and wrong ratio messages on the display. Earlier I had put in a Sonnax kit and new separator plate hoping that would solve it, which it didn't. So, of course I ordered a rebuilt torque converter and full steels, seals, and frictions for the ZF 6HP26 transmission. Yesterday I dropped the drive shafts, part of the exhaust, cross member, transfer case, and (after much fighting with stuck dowel pins) the transmission. During the rebuild today, I measured the thickness of the steels/friction stacks and they were nearly identical to the ones that I was putting in. No real burnt anything in the clutch stacks/packs. I replaced some of the bronze bushings (the easy ones) but the ones I took out weren't that loose.

I'm going to fill it and reinstall in a day or two but I really don't want to install it, only to have to remove it again. To be honest, it was a fairly easy rebuild. The bronze bushing things are a bit finicky and if you do them all, very time consuming.

Questions:
1. Any one rebuilt a ZF? Any gotchas?
2. Thoughts on the no-difference clutch stacks? The ones I was putting in were dry and the ones that I was taking out were wet but the ones coming out weren't worn to the steel inner plates either.
3. The rebuild kit I purchased was for the model/serial number but for the E clutch, there was one extra friction and two extra steels. I built the clutch stacks exactly like they came out and there was no way to put another two steels and frictions in. Does BMW or Ford have a little bit bigger E clutch? Plus, the E drum is for 4th, 5th, and 6th, which I wasn't having problems with.
4. Last one...could the flares be from the solenoids? If I move them around (matching colors of course) could I move my problem to at least find the offending part? Much easier to replace a solenoid than redo a transmission.

The particulars:
2005 Land Rover LR3 HSE
NA LHD, 4.4L AJ-V8
157,000 miles
ZF 6HP26 (1038 020 044) transmission
Steel transmission pan and separate filter

Any feedback who's done this type of nonsense would be appreciated.

For the e pack I remember the same problem, but don’t remember the solution. In the end I think I mic’d The whole stack and tried to replicate the overall height.

Buy a solenoid kit at the same time, you are almost there, why stop at that.

Do a bench fill on the trans with pan off upside down. Plug cooler ports and hand turn the trans while pouring in fluid.

Good luck.

Flares are typically sticking pistons, valves, or solenoids (rarely solenoids). Usually the pistons due to wear in the seals and the bores. I am not a ZF expert, but those are common issues in GM transmissions.

Good luck

OK, got everything back together and no leaks (used the Ford 6R60/75/80 pan gasket for a MUCH better seal).

Done:
Transmission rebuild (frictions, steels, o-rings, seals, 5 of 12 bronze seals)
Mechatronic rebuild (minus solenoids)
Rebuilt torque converter
Filled according to LR instructions

Not done:
Resetting computers!!! I thought the hard part would be getting the mechanical work done...WRONG! I have JLR SDD installed and a MongoosePro, which works great. The problem is, I can reset transmission adaptation and such but I have a constant "transmission fault", "HDC fault", and the parking brake sets if the vehicle goes anywhere near "P". Plus, SDD shows no interface to the air suspension control but I can use the DTC function to either fully lower or fully extend the suspension. I tried "Replace transfer case" option but I get an error saying no interface to the TC module, yet in the main diagnostic screen, it sees the TCM fine and reports no errors?

I have a newish battery and it is paralleled to another battery with charger to mimic a battery power supply required for SDD to function. I didn't have any of these errors before doing the rebuild. Any thoughts? I'm struggling!! :dunno:

By the way, abran bench fill suggestion was excellent except you have to plug the cooler ports AND the vent on top. Otherwise you end up with transmission fluid covered shoes!

Oops, forgot that one.

OK, to close the loop. After futzing with SDD for hours chasing HDC errors, transmission faults, air suspension faults, special program inoperative, transfer case inoperative, and parking brake inoperative, I found the culprit. I missed a three wire connector on the back of the transfer case. Plugged that in, ran the "transfer case - new install" in SDD, which calibrates the clutch and solenoids in the TC, and tada!! Someone said in a forum that the more errors that happen at once, the less serious it is. Amazing that one connector could literally and completely disable a vehicle.

Oh well, my little blue golf ball runs great now (Colorado hail storms). Needs some miles to relearn the transmission adaptions but that will only take a day or two. All-in-all, really not to terribly difficult for being a notoriously difficult vehicle. I will say, without SDD, there is no way I would ever have gotten it to move.

To anyone that undertakes, just make sure you are careful with the transmission disassembly/assembly. There are a couple of fiddly bits that must be put back in the right order and orientation. Other than that, you just need hand tools, some jack stands, and a transmission lift. Oh and take out the center console and shifter to get to the two bolts on the top of the transfer case; way easier than trying to get at them from the side or back. Also, drop the gas tank to give you 1000x more room.

Well done, most make the ZF6 out to be a scary monster but it is just another auto trans.

Last entry.

Transmission is back together and in the truck. Ended up putting it all back in, filling with fluid, resetting the adaptations, and nothing changed. It shifted and flared actually worse than before; should have listened to abran. Anyways, got a BMW solenoid kit from a place in Denver for $315. Since ZF only makes a couple of solenoids, as long as you match the colors, it doesn't matter what they are meant for. The individual ones are $185/each from most places but the BMW version (searched by ZF kit number) worked perfectly for much less.

She shifts like new and zero leaks or problems. I used Mercon SP fluid because it's easy to get and cheap but smells like microwaved vomit and I swear it can climb up a wall (capillary action). All-in-all right at $1200 for all of the parts and torque converter and around 30 hours total for R&R&R, including go backs and triple checking all of the parts going into the case.

Case closed! Ready for another 160k miles. :cheers:

Good job!

I’m always paranoid of doing a job twice, so I do it all the first time.

Yeah well done, its job most wouldn't undertake. I would because i would baulk at the 6.5K for a rebuilt trans.