When I am accelerating and it shifts to third gear the torque converter locks up a couple of seconds or so after and then, when it shifts to fourth with the converter still locked and the converter immediately unlocks, and the rpms go back up then it will lock again. It has always done this since I first bought it with 60k on it. I now have 109k on it. It's kind of annoying because it lurches when this happens. If I accelerate and ease off before the torque converter can lock in third, it will shift to fourth and then I get back on it and let the converter lock.

 

Not normal. It is going to unlock and relock on shifts but it should be seamless. The only time you should actually notice it is when it initially locks and then only by watching the tach or the sound of the engine. Even if you were trying to "feel" it there should be absolutley no tactile indication of lockup. Ears plugged and eyes closed, you should literally not be able to tell anything.

Just an FYI if you're going to fix it and go with Genuine parts, an entire exchange transmission assembly is cheaper than just the torque converter and does come with the converter. Don't ask, I can't explain it. The Genuine exchange transmissions are remanufactured by ZF and not rebuilt. Basically it's all new parts in an old case and priced right around $2,800.

Love the quote in your sig BTW.

 

So, do you have any fault codes, have you checked your fluid level and when was it last serviced?

 

Tee, no disrespect, but where are you paying 2800 for a torque converter. 3 minutes of searching and you can find a roverland part for 375. And im sure even the dealer is cheaper than that.

 

Genuine from the dealer is over $3,100. $2,800 is MSRP for an exchange transmission from the dealer. The entire transmission, which comes with the TQ is $2,800 yet the TQ alone is $3,100.

Transmissions and their related parts are the only thing I wouldn't put on used if you paid me. The possibility of contamination is just too great.

 

Completely understandable about contamination. I share the exact same sentiment about trasnmissions. However, I refuse to belive that a tc for our transmissions can only be bought at the dealer. and for $3000. Was that installed price. Was labour added to that. Sorry to ask so many questions, but I would like to know. Im sure of lot of us do.

 

Oh, no, sorry if that was misleading. The dealer is not the only option at all.

Ok, MRSP, part only and no labor on torque converter is $3,389.78.

MSRP Complete exchange transmission assembly with TQ, again parts only, $2,816 for the 4.0 or $2,947.21 for the 4.6

Those prices are actual MSRP without the extra 20-50% markup some dealers slap on so you could be quoted even more.

Personally if I needed a new converter I'd find a shop that exclusively specialized in ZFs and have it rebuilt with uprated clutches - prob around the $350-500 mark. ZF factory remanufactured units are now also available on the secondary market but the LR 4HP derivatives have proven difficult to get ahold of. If you want to ship your transmission to one of the ZF Service centers they'll remanufacture yours (including converter) for about 1/2 the dealer price. For me, by the time I'd figure in freight and inconvenience I'd just pick one up in the green and white crate. Not that it really makes any difference but the LR transmissions are remanufactured in Germany also.

I know I'm probably unusual in this but I'm just a fan of Genuine parts from the local dealer. It's convenient plus I know I'm getting a quality product with a warranty.... The day the boxes start saying "made in India" will be the last day I buy Genuine parts, however. It's only a matter of time I'm afraid.

Anyway, sorry of previous posts were unclear - certainly not my intention.

 

Might be tough, but anyway to get a video of this happening? Would be helpful to see the RPM's and hear the sounds. As Mike said, you sure your fluid levels are OK and clean?

 

I'll try to get a video of it later. I have a magnaflow muffler so you should be able to hear it. It has always done this since I can remember. It locks in third shifts to fourth and an immediately unlocks and then will lock once you reach the right speed. I haven't serviced it in a while (about 40k miles) so I will start with that. I have heard not to go with the machine that changes all of the fluid. If I am easy on the throttle and feather it before it shifts to fourth it isn't nearly as noiticable but I know it shouldn't do that. I am going to start with a filter kit and change the fluid in the pan, run it and maybe drain the pan and fill it again.

 

To me, it sounds like a software issue - Especially if you're not having any other symptoms, if it was an oil pump/pressure issue you'd see it other places as well. You could try resetting the adaptive values, but honestly I don't think its going to do anything for what you're experiencing. Always worth a shot though.

Could also be an issue with the solenoid sticking, solenoid three is the one for the lockup. There's one of those mechanic in a bottle products that removes the varnish from everything in the tranny but I can't remember what it's called. There could be a delay between the ecu energizing the solenoid and it actually opening.

To your comment about the machine flush, totally agree. No way I'd chance it.