Thread: Gearbox / Motor Vibration SDV6

Originally Posted by Eric SDV6SE

After 182,000 kms, lots of towing campers and boats, I will be rebuilding the ZF valve block in my ZF6HP28 X transmission. This includes: brand new solenoids, new valve kit (all O-rings, accumulators and springs, seals etc.), new separator plate, mechatronic pump seals, plus new sump filter and metal pan gasket.

Metal pan upgrade and flush was done at 120,000km.

The symptoms I've currently got is harshness in down shifts 3-2 and 2-1 (no clunk....yet), delayed up shifts (especially 5th to 6th) and sometimes hesitation or throttle flaring when shifting between all gears.

No shudder at all, and the TC still locks up nicely, its just the shifts that are cause for concern.

Putting it in Sport mode makes it feel only slightly better, but this is only because the line pressure in the valve body is increased to allow faster shifts and holding gears longer, but it effectively masks the real issue. Manually shifting up or down in Sport mode still gives the same harsh feel.

I found out that this is caused by the accumulator valves being worn, and most probably the solenoid nozzles being partially blocked. This results in pressure loss in the valve body, and more than likely the pump bridge seal is probably split, and the 4 pump seals are also probably pushed all the way into the valve body, when they should be sitting about 5mm proud.

Before I start burning out clutch packs and damaging the torque converter, i figured now is a good a time as any. A new transmission is approximately A$7k supply only...

Penrite has their new BMV ATF available that is a suitable replacement for the ZF Lifeguard 6. It is also more that 50% less cost than LF6 (20L of BMV costs A$220 delivered to my house, from SuperCheap Auto)

I spoke to the Penrite tech support people and this gave me a lot of confidence in making my selection. I hope that this will possibly lower the cost of LF6, but wont hold my breath though...

Using all genuine ZF parts (i.e. Sonnax solenoids and ZIP kit), with the exception of the filter (OEM) and pan gasket (thicker Duoprene aftermarket one that seals the pan better), and the Penrite BMV ATF cost me A$1200 so far.

As I'm intending to keep the vehicle for the foreseeable future, and we a planning a Great Central Road trip next June, I think this is cheap insurance.

I would also strongly recommend to do this at the same time as the plastic-to-steel pan and separate filter conversion.

Note that this exact same transmission (ZF 6HP series) is used in late model BMW's, Jags, Fords and there is loads of info available on their respective forums about trouble shooting etc.

You will need to check using your VIN if you have the 6HP26 (gen 1) or 6HP28 (gen 2), depending on the build date of your car. I believe most D3's have the Gen 1,

I will let you all know how it goes, rebuild is planned for the next couple of weeks (currently waiting for parts from O/S)

Note - I will also be changing the transfer case oil, front and rear diffs I did 4 weeks ago and no issues (oil from the rear was still clear, the front also clear but a bit darker after after 180,000km!)

Cheers

Interesting post Eric, I will be keen to know how you find the penrite bmv.

[QUOTE=Had an audible hum in the cabin also. Nothing really thought the steering wheel, more felt though the chassis. Bearings and tyres all good so ruled them out. Still there on occasionally but yeah, 90-95% better. /QUOTE]

Have you had a look at the prop shafts from the transfer case to the front and to the rear diffs?

These are dynamically balanced at the factory. Sometimes, should they need it, the may have little weights (plates) welded/ soldered on (just like the ones on your wheels) if they required it at the factory.

If these come off, or if the shaft has ever had a knock, it could be that the vibration is coming from them. As the rpm's increase, the shaft moves through different resonance frequencies and these match with a natural frequency, this will amplify them. From your posts, it appears at usually the same RPM.

Also check the prop shaft to transfer case flange bolts and at the prop shaft to differential input flange. if these are not to specified torque, the flange connection may flex, also causing vibration.

Also, check and get your wheels dynamically balanced - some tyre places can also even rotate the tyre on the rim to find the best balance between them, before dynamically balancing the wheel assembly. Although an unbalanced wheel normally leads to quite noticeable steering wheel shudder, not a through-chassis vibration....

Just a couple of thoughts....

Cheers,

Eric

A rear wheel imbalance is felt through the chassis versus front wheel which is in the steering wheel

So the dreaded shudder has returned which is a little annoying, even with the shudder stop. Shifting, gear selection etc are still all fine though.

I went to my local transmission place yesterday which specialises in ZF and he said he is rebuilding 2 of these boxes a week, but the shock for me was the $7 - $8K repair estimate with 24 month/50,000km warranty. He said the TC is most likely the culprit and I could just replace that for $3K which might solve the issue for 6 months and start to have other issues and since teh box is a bugger to get out more cost effective to do a complete rebuild. I had a look at one on the bench in the process of being rebuilt and although there are alot of components its not overly complicated and teh principle of operation pretty straight forward. He also showed me the separator plate in the valve body and you could see where the gasket material had degraded over time allowing the fluid under pressure to bleed into adjacent galleries. This will cause shifting issues.

So with that shock slowly settling in my research has ramped up. For now I am going do a complete flush and add some more shudder stop. This may or may not work but for $400 a small price if I can delay the rebuild. I'll do the flush via the trans cooler hoses using a pressure pot to add to the new oil back in. 11 litres should completely change the fluid out. Seems lots of people have stopped the shudder with a full flush (but i'm not sure if they had shudder stop before) so fingers crossed.

If that doesn't work then its time to rebuild. Parts list will most likely be:

- Torque converter.
- solenoid valves (I could have them flow tested but a full kit is cheaper)
- seperator plate
- mechatronic sleeve
- full set of shaft bushings
- full set of gaskets, o'rings etc.
- inspection of the fiction plates to look for burning / wear and replace as required.
- sump filter
- shudder stop $10 from REPCO
- tub of Assembly GOO in the green colour.

I was recommended to only use the ZF fluid and parts as although other companies have oils speced the same he said it wasn't worth the risk. The same was never to use aftermarket parts. All should say made in Germany. I tend to agree although there will be some salesmanship in there. The penrite BMV is $40 for 4 litres so just over a 1/4 of the price. So very tempting but without a vehicle that has run years on it there is just no history to say it is ok to use.

I think with the rebuild that part cleanliness and no contamination during assemble are the key. I have read that even small cotton fibres can get into the solenoids and cause issues.

Now to start looking for places where I can purchase the parts and get a budget together.

Keep this thread up to date with how you get on finding the parts. Interested in a DIY rebuild at some stage too.

Check out the US landrover forums as there are a couple of guys that have rebuilt their auto .

Brad72, I had the oil changed, metal pan and filter etc, it didn’t fix the shudder which sounds very similar to what you describe. Then shudder disappears as soon as you click it over to sports mode. Which the dealer agrees confirms TC issue. If anything it has probably got a little worse since I did oil change.
So I think will just put up with it until something worse happens and forced to rebuild gearbox.

Originally Posted by Hungo

Brad72, I had the oil changed, metal pan and filter etc, it didn’t fix the shudder which sounds very similar to what you describe. Then shudder disappears as soon as you click it over to sports mode. Which the dealer agrees confirms TC issue. If anything it has probably got a little worse since I did oil change.
So I think will just put up with it until something worse happens and forced to rebuild gearbox.

Thanks mate. There is evidence that yes it can get worse due to the new oil having a slightly lower viscosity. Maybe for you a full flush and some shudder stop might fix things. I was also told that the second oil change might fix it as well. A real bugger that LR sold the vehicles saying the boxes were filled for life and therefore never recommended to have the box serviced. Oh well.