10 LR4 Transmission Fault Warning while towing 7000lbs

[fiatlux]

Hello,

I'm a new member here and recently got 10 LR4 with 100,000 miles on. After through research, I concluded that LR4 is a good tow vehicle. So, I pulled my 6,700 lbs Heartland 32 ft travel trailer to a near by state park yesterday. It was good start. Air Suspension worked beautifully. Tow Icon comes on and works fine, it seems. Plenty of power. Not much sway. I used Manual and Sports Mode gear shift to make sure it got enough power.

Here come the question: After one hour of driving, it jerks couple of time to find right gear between 3 and 4, Transmission Fault Yellow warning on Then, it seems Tranny locks in 3rd gear only. I hardly reached campground in "limp mode". Once the engine is off. It goes back to normal. Unhooking the trailer, and driving without a trailer, tranny is very smooth and no issue. Next day, on the way back, it happens again. I was manually shifting between 2nd -4th gear on hilly road. I tried maintain 2500 to 3000 RPM all the time. But, Transmission Fault warning.
Can anyone tell me what could be a problem? Do I need to scan the code first, would I need new transmission? Thank you.

 

[jettore]

Is that 6700 lbs dry weight?

Did you get any maintenance history? If so, see if any transmission fluid/filter service was done.

 

[fiatlux]

jettore/ Yes, it is dry weight. with food and gears, it's near 7000 lbs. I do not have full history. I highly doubt that the transmission oil change was done.

Any other suggestions, idea?

 

[Pfunk951]

Did you get any shuddering when it was jumping in between 3 and 4?

If you don't have any maintenance history on it, I'd change the fluid and filter, reset the codes, and see if it comes back.. AFAIK, it gets expensive from there as I haven't heard of people working on these, per se(solenoids, etc..).

Mike

 

[fiatlux]

pfunk951 / Thanks for the comment. I did not feel any shuddering or trembling. Just momentary hesitations a couple of time and then the warning.
Does the fluid & filter change make big difference? 100k miles old fluid would be bad enough to influence the dynamics of tranny behavior? The load weight itself shouldn't be a problem, since it's below its capacity, right?

 

[Pfunk951]

It made a significant difference in my shifting, but the heaviest thing I have hauled is a truckload of my wife's friends and maybe a 2,000 lb trailer from time to time..

Here's what I know, and don't know:

These ZF transmissions operate differently than most of the transmissions I have dealt with- I'm not familiar with the clutch configuration/operation, or how the solenoids operate them. Saying that, last month I "cured" a Honda Pilot transmission (with about 100k on it, tows a lot in the summer) that was behaving horribly as the driver missed a R&R on the fluid. That fluid contained a good amount of clutch material that was causing gear confusion and a very noticeable shudder. I changed the fluid twice, and it went away and continues to operate smoothly..

Did I really fix anything? Absolutely not, all I did was put fluid in it that wasn't saturated with clutch material, allowing the transmission to engage and shift the way the programming told it to. But again, different design- but perhaps the same principle.

ZF is the manufacturer of our transmissions. They call for fluid/filter changes at 60k. Land rover calls for one at 120k (I think) and some LR techs will tell you they are filled for life. I am hoping that in your case a fluid change might help or remedy the situation, in order to avoid the contents of this next sentence: Replacing (or rebuilding) your transmission is going to get expensive fast, I haven't heard of anyone getting out of that for under $5k for a rebuild.. You can double that for a new one.

Hope some of this makes sense..

Mike

 

[Huy Tran]

I wouldn't be surprised if you pulled your code and get a P2704.
My 2010 with 95k has done the same thing you're describing. The last two times occurred after I've been in traffic for over an hour (Houston). So I'm suspecting it's related to fluid temperature and worn stator bushing. Other vehicles (BMW mostly) with the same ZF transmission has reported the same problem. The bushing to the E clutch pack gets worn and fluid will bypass it and prevent engagement of 5th and 6th gear. In my case, after 4th gear, the car will rev above 5k rpm but will only maintain 30mph. Like it's stuck in a lower gear. Problem goes away after the car is shut off for 15-20 minutes.
I have done the ZF fluid and filter change but that did not solve the problem. I was also going to try replacing the rubber valve body sleeves and seal too. Maybe that and a better oil cooler could help.
In the end, I think a rebuild is going to be the answer.

 

[fiatlux]

Huy Tran / Thank you for the input. My wife, kids and I were so happy getting this LR4 in right color. So it's somehow sad story to hear your advice about the incurable imperfection. It probably sounds stupid, but I bought this car for mainly towing purpose for the TT. I thought it's capable, after reading many stories and personal experiences in this forum. I guess I have to keep the LR4 for just joyride purpose for a year or two, meantime I have to buy a Ford/GMC half ton truck. When I was considering tow vehicle, two final candidates were LR4 and early 2000 Ford Excursion 7.4L Powerstroke Diesel. I have never owned a diesel and my affection to Land Rover was too much. So I'm here.

 

[Pfunk951]

Does Huy's issue seem to be the same as yours? I would hate to de-commission the rover without a definitive diagnosis..

Damn fine rig..

Mike

 

[fiatlux]

Pfunk951 / There are some similarities of the symptoms. I'm still not sure about if the tranny temperature went up abnormally high, though. Because if the temperature was an issue, it should have displayed 'transmission fault due to high temperature' warning, not just 'transmission fault'. I guess I have to try oil change first and go from there.
Surely, the set up looks great, to me. I wish it worked as good as it looks.