Tranny slips 3rd to 4th

[IslandStyle]

Hey all,

My '11 LR4 (143k miles) is experiencing intermittent slippage at ~30MPH usually when coasting or decelerating. If the pedal is down, no issues except for a slight shimmy that I just noticed today. It's a recent event but is happening once every other day. I've searched this forum and the other LR forum. What I've found so far:

1. I've seen Mr Mike G's take on mismatched tread depth or sized tires confusing the software. I can't tell if this pertains to LR4s as his posted advice was on an LR3 (Yep, get both have ZFs, but not the exact same plus possible difference between '10 and '11s??). I happen to have a 1mm variance between rear and front tires (5, 6mm respectively...time for new shoes, I know) and just rotated them. This could be a read flag, but I think slippage occurred prior to rotation.

2. Vegas heat kills batteries. I've read poorly performing batteries may mess with software. Can't correlate exactly if slippage occurred previous to dying crank. Seems like it was prior. Battery replacement had no impact. I assume SW could still be corrupted.

3. Rear brake lights problems can mess with software (lights functioning fine, so skipping this one)

4. LED interior bulbs messes with software (upgraded these 5 years ago, can't see how it would manifest now). I read a fuse could impact the transmission as well. This wasn't very clear to me.

5. Change the transmission fluid and hope for the best

6. Source a new tranny or dump the rig

As you can see, I've read a bunch. Everyone's posts and advice are so very helpful. Oh, I guess I could have the SW flashed/upgraded too. I was hoping to turn my truck into a weekend crawler for the last 40-50k miles of its life, but not sure I want to put 5k into a tranny to do it (or buy new tires to find out the tranny's dead).

Am I missing anything else? Oh, no visible leaks.

Order of troubleshooting seems to be:

Flashing code (I've read this could take up to 3 times which seems like a PITA, but a one-time charge)
Change transmission oil...wait and see
Buy new tires, source a low-mileage used tranny or dump it

I love my rig and wanted to convert it to something more fun. I'm wondering if I need to let go of that plan/dream. This seems therapeutic lol. Thanks for reading if you made it this far.

Any guidance or missed troubleshooting callouts would be appreciated. Cheers.

 

[Quijote]

That's a high-mile car. Do you know the history? How many transmission fluid changes has id had and when? I have "low mile" 2013 (27k miles and turns 4 years old in 2 months) but I've been reading that this vehicle should have the fluid changed sooner than most others. I may change mine at the ~40k mile mark, which should be about 6 years since new.

 

[IslandStyle]

It's been mine since Day 1. I stuck with recommendations from LR Service, so not as frequent as you or other users, I'm afraid. Given that I've followed mfg recommendations, I'd hope I'd be immune from mechanical failure, but that would be ridiculous belief. I guess I'm cutting bait which bums me out.

 

[Fields Carlisle]

I'm having rough, slow shifts in my 11 LR4. It has 76K miles, to my knowledge hasn't ever had transmission service, but I'm thinking it's the classic ZF 6HP valve block or solenoid issue. I get a slight 1 second delay when engaging reverse, and it just sorta slams into gear. Shifts from 1-6 are slow compared to other LR3s and LR4s I've driven. I also get a slight harmonic resonance at speeds of 25-40 when accelerating. I know the valve blocks and solenoids are a common problem with the ZF 6HP transmissions, so I'm just guessing that's it. I really hope I'm not looking at a new transmission.

 

[IslandStyle]

I'm having rough, slow shifts in my 11 LR4....I know the valve blocks and solenoids are a common problem with the ZF 6HP transmissions, so I'm just guessing that's it. I really hope I'm not looking at a new transmission.

Curious, are you waiting for an eventual failure or going proactive mode. I've priced out Transmissions...2400-3500 plus labor. I'm on the fence. Everything else runs great. I don't want to be pollyanna but I expect to hit 200k on V8s. Seems like giving up, if that makes any sense. My GS is purring along at 221k. Apples/pomegranates, I know.

 

[Fields Carlisle]

Curious, are you waiting for an eventual failure or going proactive mode. I've priced out Transmissions...2400-3500 plus labor. I'm on the fence. Everything else runs great. I don't want to be pollyanna but I expect to hit 200k on V8s. Seems like giving up, if that makes any sense. My GS is purring along at 221k. Apples/pomegranates, I know.

I have to figure out what's going on because it's really taking away from my enjoyment of the vehicle. I've been told to either get a transmission service (oil and filter/pan), or not to do that as it will break the transmission. I've got no idea what to do. This is my first car with an automatic transmission. I've always preferred manuals (still do) because of their simplicity and ease of fixing. This transmission issue annoys me as the CPO warranty just expired in March. I've looked to see if there's any transmission SW update available and don't see any for our year and model, but that's going off of what IIDtool said.

 

[VernB_LR4]

My Rover Mechanic has a ton of experience with the LR's and ZF's... His take on this is not to change the transmission fluid more than recommended as he has had multiple fail shortly after a change and takes the if it aint broke don't F with it approach. He feels the fluid changes are expensive and the money you save on them can be best applied to fixing the tranny when you really need to. I am not sure about this... do people on the forum have any experience with failed transmissions shortly after a fluid / filter change? My rig has just over 100,000 miles (160,000Km) and is a 2011 so is 50,000 miles (80,000Km) or 4 years away from the scheduled maintenance.

 

[IslandStyle]

Update: I checked the code with the dealer and he told me it wasn't (rattled off a few diff Transmission codes) that would be fixed with a SW upgrade. Yeah, he wished me luck and gave me a quote for $6k for them to replace with a rebuilt. After making a few calls to a number of Transmission repair shops in town (who wouldn't touch a ZF btw), the local AAMCO referred me to their former "best mechanic" who opened his own shop and worked on ZFs. When I pulled up to the shop, I saw (2) 7-series and a few Mercs as well (whew). After a week and 3k-ish later, I have a fully rebuilt transmission. Time will tell, but I've got a 1Y/12k mile warranty on his work. I had him look at the Diffs and TC oils, and he told me they weren't dirty and he wouldn't bother changing them. That's not how I usually operate, but I needed my rig back so I have those services coming up next. Had to buy new shoes for her which set me back another 1k (I replaced my Coopers with Bridgestones - not as mean looking but way less road noise AND $450 less with rebates ), so axel service needs to wait til next month.

 

[Fields Carlisle]

Update: I checked the code with the dealer and he told me it wasn't (rattled off a few diff Transmission codes) that would be fixed with a SW upgrade. Yeah, he wished me luck and gave me a quote for $6k for them to replace with a rebuilt. After making a few calls to a number of Transmission repair shops in town (who wouldn't touch a ZF btw), the local AAMCO referred me to their former "best mechanic" who opened his own shop and worked on ZFs. When I pulled up to the shop, I saw (2) 7-series and a few Mercs as well (whew). After a week and 3k-ish later, I have a fully rebuilt transmission. Time will tell, but I've got a 1Y/12k mile warranty on his work. I had him look at the Diffs and TC oils, and he told me they weren't dirty and he wouldn't bother changing them. That's not how I usually operate, but I needed my rig back so I have those services coming up next. Had to buy new shoes for her which set me back another 1k (I replaced my Coopers with Bridgestones - not as mean looking but way less road noise AND $450 less with rebates ), so axel service needs to wait til next month.

God I hope I don't have to do the same thing. I just blew $1100 on transmission service and new serviceable pan/filter, spent $1500 a month ago on control arms, calipers and rotors and I'm still experiencing the same transmission clunkiness as before.