Gear box issues 2nd gear only

[coopers1969]

Hey guys have a 3 litre D4 with a 6 speed brought the car with 96000 km the transmission had the old plastic pan. Gear box was fine no issues but replaced with a metal pan and did a home flush of about 18 litres all good. Over the last couple of months I have noticed, worst when it is cold that when the car goes from 1st to second the change is smooth but after a few seconds the reves drop about 600 revs then it hooks up and grabs 3rd. It gets better when the transmission warms up. Doesn’t happen in any other gear and there is no flaring at any speed.
Any ideas I have searched but most people talk about flaring in higher gears when at highway speeds.
Cheers [emoji482]

[Eric SDV6SE]

Rebuild the valve body. My guess is the solenoid for 2nd gear is blocked, or the valve line for second gear is leaking that badly it jumps to third.

All shift related issues are because of the valve body leaks, fluid bypassing and probably partially blocked solenoids.

Youll need the Sonnax gen2 zip kit, new solenoids, new mechatronic seal and valve body to transmission seals, new filter, pan duoprene gasket and valve body separator plate. All available off ebay, just check youre buying genuine. Parts above should cost you about 1200. New fluid too, as you may have a lot of particles swirling around.

Alternatively, you can filter the fluid you drain out, go to a paint store and get a packet of paint filter papers, then go to supercheap and get two new plastic oil drain containers. Bit fiddly but do able.

Removing the valve body is relatively easy, dont forget to wear an antistatic bracelet strap that is earthed to avoid frying the mechatronic with a static discharge. The sonnax zip kit contains full valve body rebuild instructions and exploded diagrams,plus their website has lots of info.

Rebuild will cost you around 1200 - 1500 depending on if you go new ZF fluid or reuse what you have (filtered), a new transmission will cost you 7-8k supply only, rebuilt / recon tranny will be less of course.

[DiscoJeffster]

I have a set of brand new genuine solenoids for sale (ended up with two sets) in case you’re interested to DIY it? I’m doing mine next week.

[coopers1969]

Rebuild the valve body. My guess is the solenoid for 2nd gear is blocked, or the valve line for second gear is leaking that badly it jumps to third.

All shift related issues are because of the valve body leaks, fluid bypassing and probably partially blocked solenoids.

Youll need the Sonnax gen2 zip kit, new solenoids, new mechatronic seal and valve body to transmission seals, new filter, pan duoprene gasket and valve body separator plate. All available off ebay, just check youre buying genuine. Parts above should cost you about 1200. New fluid too, as you may have a lot of particles swirling around.

Alternatively, you can filter the fluid you drain out, go to a paint store and get a packet of paint filter papers, then go to supercheap and get two new plastic oil drain containers. Bit fiddly but do able.

Removing the valve body is relatively easy, dont forget to wear an antistatic bracelet strap that is earthed to avoid frying the mechatronic with a static discharge. The sonnax zip kit contains full valve body rebuild instructions and exploded diagrams,plus their website has lots of info.

Rebuild will cost you around 1200 - 1500 depending on if you go new ZF fluid or reuse what you have (filtered), a new transmission will cost you 7-8k supply only, rebuilt / recon tranny will be less of course.

What does the son ax kit contain?

[josh.huber]

I have a set of brand new genuine solenoids for sale (ended up with two sets) in case you’re interested to DIY it? I’m doing mine next week.

How much? I'm also thinking I'll buy that spare separator plate you'll have left over.

[coopers1969]

Rebuild the valve body. My guess is the solenoid for 2nd gear is blocked, or the valve line for second gear is leaking that badly it jumps to third.

All shift related issues are because of the valve body leaks, fluid bypassing and probably partially blocked solenoids.

Youll need the Sonnax gen2 zip kit, new solenoids, new mechatronic seal and valve body to transmission seals, new filter, pan duoprene gasket and valve body separator plate. All available off ebay, just check youre buying genuine. Parts above should cost you about 1200. New fluid too, as you may have a lot of particles swirling around.

Alternatively, you can filter the fluid you drain out, go to a paint store and get a packet of paint filter papers, then go to supercheap and get two new plastic oil drain containers. Bit fiddly but do able.

Removing the valve body is relatively easy, dont forget to wear an antistatic bracelet strap that is earthed to avoid frying the mechatronic with a static discharge. The sonnax zip kit contains full valve body rebuild instructions and exploded diagrams,plus their website has lots of info.

Rebuild will cost you around 1200 - 1500 depending on if you go new ZF fluid or reuse what you have (filtered), a new transmission will cost you 7-8k supply only, rebuilt / recon tranny will be less of course.

Also sorry it doesn’t jump to third I accelerate slowly 1st to second normal picks up second the drops reves with no change in throttle position. Then it hooks up in second and changes gear to third as per normal. It is the drop in reves in second with no throttle change that is strange. And there are no fault codes either I feel the full service with parts suggested could be the way to go. Are there any YouTube videos showing how to do it?

[Eric SDV6SE]

ZF6-GEN2-ZIP - ZF6HP21, ZF6HP28, ZF6HP34 SONNAX ZIP KIT (https://transpartswarehouse.com/zf6-gen2-zip-zf6hp21-zf6hp28-zf6hp34-sonnax-zip-kit.html?network=g&device=m&keyword=&campaign=10381381880&adgroup=pla-295206971696&gclid=CjwKCAjw0_T4BRBlEiwAwoEiAcGgVSDZQQ3Uw2rZL6hd 3WIdT0GIZA1gqNot2T7iz9J6EVqlQq6rfRoCAFEQAvD_BwE)

Or google sonnax gen2 zip, pretty self explanatory.

[DiscoJeffster]

How much? I'm also thinking I'll buy that spare separator plate you'll have left over.

They owe me AU$380.

As for the plate, it’ll depend what one your box needs. It’ll be a win if it’s the one mine doesn’t need - there are two for our box so Russian roulette. I’m doing mine next Monday so I’ll let you know which one I have spare.

[coopers1969]

ZF6-GEN2-ZIP - ZF6HP21, ZF6HP28, ZF6HP34 SONNAX ZIP KIT (https://transpartswarehouse.com/zf6-gen2-zip-zf6hp21-zf6hp28-zf6hp34-sonnax-zip-kit.html?network=g&device=m&keyword=&campaign=10381381880&adgroup=pla-295206971696&gclid=CjwKCAjw0_T4BRBlEiwAwoEiAcGgVSDZQQ3Uw2rZL6hd 3WIdT0GIZA1gqNot2T7iz9J6EVqlQq6rfRoCAFEQAvD_BwE)

Or google sonnax gen2 zip, pretty self explanatory.

Thanks for all the info I have looked on eBay for the solenoids but the genuine ones I am unsure of did you use bmw or food ZF solenoids or do you have the link where you got yours from.

[josh.huber]

They owe me AU$380.

As for the plate, it’ll depend what one your box needs. It’ll be a win if it’s the one mine doesn’t need - there are two for our box so Russian roulette. I’m doing mine next Monday so I’ll let you know which one I have spare.

I'll pm you. I'm not keen on Russian Roulette. I was going to take your approach and get both. Then I'll offer the unused one on here for someone else to follow.

[Eric SDV6SE]

Thanks for all the info I have looked on eBay for the solenoids but the genuine ones I am unsure of did you use bmw or food ZF solenoids or do you have the link where you got yours from.

As long as they are for the right ZF gearbox and genuine it shouldn't matter. BMW and others run the ZF gearbox platform in their cars as LR does.

I know that BMW run the same ZF units, so pretty safe there.

If your D4 3.0l is pre 2014, I'm guessing its the 6HP28 unit. Check under the car up on the lhs of the gearbox theres a reference plate. Note down the numbers as this identifies the gearbox.

I bought mine from a mix of places, solenoids came from a US based official ZF agent, the separator plate from my local ZF distributot etc.

Re the separator plate, pretty sure yours would be the A063 plate. They should be in stock locally so you shouldnt need to buy two and be left with one you cant sell.

[BobD]

Also sorry it doesn’t jump to third I accelerate slowly 1st to second normal picks up second the drops reves with no change in throttle position. Then it hooks up in second and changes gear to third as per normal. It is the drop in revs in second with no throttle change that is strange. And there are no fault codes either I feel the full service with parts suggested could be the way to go. Are there any YouTube videos showing how to do it?

There is probably nothing wrong with the car. The torque converter locks up as revs rise in second gear at around 2500 and then stays locked up in all gears above that. That is normal for my D4 6 speed , my L405 8 speed and now my new D5 8 speed. You notice it more under load but that is always what happens on any take off from a standing start unless it changes to third at lower revs before the TC lockup occurs. Happens in second gear on 6 speeds and maybe second or third on the 8 speeds as it is difficult to tell what gear it uses from a normal standing start with the 8 speed and I haven't tried to work it out.

[Eric SDV6SE]

Roger that. Car can and will take off in second and tc locks up as stated, but should not drop 600rpm unless its changing gear.

A test woukd be to shift into sports mode and accelerate briskly. Should move through each gear with no clunks and hold each gear a bit longer. Remember the mechatronic is adaptive to driving styles and sometimes need an "italian tune up" to get them to wake up.

Further, "manual" shifting should also be smooth and no "thumps" up or down.

[coopers1969]

Roger that. Car can and will take off in second and tc locks up as stated, but should not drop 600rpm unless its changing gear.

A test woukd be to shift into sports mode and accelerate briskly. Should move through each gear with no clunks and hold each gear a bit longer. Remember the mechatronic is adaptive to driving styles and sometimes need an "italian tune up" to get them to wake up.

Further, "manual" shifting should also be smooth and no "thumps" up or down.

Thanks I may be jumping at shadows just don’t want a $7000 dollar bill if the S hits the fan. Though for around 1200 dollars a gear box touch up couldn’t hurt. How are you finding the Penrite fluid for the transmission.
And there is defiantly no clunking and changes down gears nice and smooth in drive and with some authority in sport mode.