Here's an article I came across about the root cause of the 'A' clutch drum failure in the ZF 5HP24 transmission-it seems that there have even been cases of newly-fitted updated clutch drums failing.

The root cause is 'uncommanded hydraulic pressure spikes' caused by wear in the pressure regulator valve in the valve block body, so this ideally needs to be rectified as well:

BMW ZF5HP24 'A' clutch failure.pdf

 

It usually happens all of a sudden-the drum is a metal part & it usually just snaps instantly, so you stop instantly

There are certain symptoms of the fault which indicate that the valve is failing & causing the start of the high pressure hydraulic fluid spikes which eventually destroy the 'A' clutch drum.

When you move the gear selector lever from 'P' or 'N' into 'D' or any of the forward ranges, you should feel the gearbox engage almost instantly-within 1 or 2 seconds. If it takes 3, 4, or 5 seconds to engage when you select 'D', then this is the first symptom of the valve becoming worn.

Sometimes the gear will not engage unless you rev the engine to around 1500rpm in 'D', then it will engage with a savage 'bang'. At this point you should immediately get the valve block repaired.

If you ignore this symptom then it will almost certainly get worse & finally break the 'A' clutch drum.

I had a BMW 540i once with the ZF 5HP30 transmission, which is basically a bigger & stronger version of the 5HP24 & used the same design. I had the symptoms of delayed engagement of the gears when moving the selector lever from 'P' or 'N' into 'D'. It would take around 4 or 5 seconds, instead of the normal 1 or 2 seconds.

Then 1 day at work, I engaged 'D' and nothing happened. So I revved the engine & suddenly at around 1500rpm the gearbox engaged with a massive 'bang/lurch'. The car still drove alright but I took it pretty quickly to a local gearbox specialist who changed the fluid & fitted new valves in the valve block body when the gearbox sump was removed.

 

Small world.
I had our ZF 5HP24 transmission rebuilt (2001 XJ8) by Nat 2 years ago (September 2010).

After our Indy shop removed the transmission and put it into my pickup truck, I brought it to Nat at Eriksonn in Old Saybrook CT.

They rebuilt the torque converter, replaced the forward disk with the updated one (existing one was fractured), replaced the worn valve body parts with the updated valve body.

I picked it back up in about a week,

Eriksson Industries is the only authorized ZF Service in the state of Connecticut.

Jim Lombardi

 

That pdf is on the forum for the last almost 2 years. I am just curious , or maybe you can consult Eriksonn and let us know, if that particular valve changing in the valve body can prevent the breaking of the A drum.
It could be a preventive measure before transmission failure,that can be done while the transmission is still in the car, like the changing of the tensioners.

As I remember, the valve is about 20 dollars, the work another 200 maybe, cheaper than a rebuilt, isn't it?

 

It certainly looks like that should reduce the chance of failure, and it looks relatively easy to replace. I'm going to download the ZF manual and do some studying. I will probably buy the valve and change it next time I change the fluid and filter.

 

The problem first appeared in BMW's, as these used the 5-speed autoboxes from an earlier date than Jaguar did. The E34 model BMW 540i came out in 1992 & used the ZF 5HP30 transmission, which had a high torque handling capability equivalent to the Mercedes gearbox in the Jaguar XJR.

The problem was noticed in the BMW's and the fault was pointed squarely at the valve block body & plastic 'checkball' valves. These plastic parts would wear out, and cause hydraulic pressure spikes which could then fracture the forward clutch drum.

The first symptoms were a delay in the gearbox engaging when 'D' was selected. At this point if the gearbox sump was dropped & the valve block body removed for overhaul & new uprated valve parts fitted, then the risk of forward clutch drum failure was removed.

In the BMW case, the fractured forward clutch drum was a SYMPTOM of the failed hydraulic pressure regulating circuit & the failure was due to sudden uncommanded fluid pressure spikes.

These spikes happened because the valves & associated metal bores in the gearbox sump valve block body wore out prematurely & allowed high pressure fluid past the gaps, which caused these pressure spikes & would fracture the forward clutch drum.

Yes, the fitment of a stronger forward clutch drum would allow it to cope with the fluid pressure spikes, but if the valve block hadn't worn out in certain parts then there would have been no pressure spikes to start with.

It was a known issue with the older BMW's using the 5-speed ZF gearboxes, then when Jaguar started using them the problems started happening there as well.

I had this issue years ago with my old E34 BMW 540i, long before the problem started to appear on Jaguar forums. If you managed to catch it in time & get the valve block/valves overhauled, then the forward clutch drum was not at risk any more.

The fitment of a stronger forward clutch drum cured the 'symptom', but not the root cause. The stronger uprated forward clutch drum was better able to cope with the fluid pressure spikes-but if the valving that controlled the hydraulic pressure hadn't failed, then there wouldn't have been these fluid pressure spikes in the first place.

The intial symptoms of failing valving were a delay in the gearbox engaging when 'D' is selected.

The valve block is much easier to access than the forward clutch drum-once the fluid is drained & the gearbox sump removed, it's relatively easy to remove the valve block for overhaul.

BMW used the ZF 5HP24 gearbox on the E39 5-series models & so had the same problems as the Jaguar XJ8's with the forward clutch drum. But the problem goes back earlier than that-all the way back to the original E34 BMW 5-series with the ZF 5HP30 transmission, which was the first design to start showing this problem as the mileage built up. The repair kits for the 5HP30 transmission contained metal checkball valves to replace the original plastic devices in the valve block body.

So once again a small piece of plastic can cause the ruinous downfall of a good car, just like the plastic secondary tensioners & water pump impellers...

 

It's not just the valve itself wearing out-the other problem is if the metal bore channel where the valve moves has also worn out. Then you're looking at replacing the whole valve block assembly too-although that's still a cheaper & easier job than dropping the whole gearbox to replace the forward clutch drum...

I had the valve block removed & overhauled on my old E34 BMW 540i, and I caught the fault at an early stage. With the new valving fitted the gearbox would engage normally again when 'D' was selected & would not do that scary trick of remaining un-engaged in 'D' until the revs went past 1500rpm, at which point it would engage with an almighty 'thud'...

 

Interesting. Could this be the problem with my Ford F350 Super Duty? It happens often on and off for the past 3 yrs.
TIA, Bruce

 

I posted the following in the forum thread "Off the road again" (10/13/2011 post# 21)

Here is some more information on the valve body parts. I call eriksson ZF transmission and found out that the valve body part# 1058 327 022 is not available and is on order from ZF. It's normal list price is $289.04 and $236.48 wholesale.

They also have a rebuilt that you can buy with oversize bore and pistons for $200 plus refundable $50 core charge.

The other part is 1058 327 068. It is in stock, list price is $369.94 and $298.58 wholesale.

I sent an email to CTSC and their reply was the same on the 1st part (unavailable) they did not mention rebuild part or the price when available. Their price for 1058 327 068 is $165.33. You might want to call them about the price (big different in price between these 2 vendors - maybe one is the casting and the other the assembly? ).
Looks like at least $400 plus to change these 2 parts.

Here is the weblink to the thread:
https://www.jaguarforums.com/forum/x...d-again-61537/

also look at post# 11 in the off the road again thread.

Jim Lombardi

 

Result from searching internet for ZF5HP24valve body:

Sonnax Part #139740-01K, Alt. vender: # W-S185741AP-1KVALVE KIT, ZF5HP24 PRESSURE REG(OVERSIZED)$42.22 plus shipping on Makco transmission parts website.

Description in Sonnax Product Data PDF:

"Wear is commonly found at differentareas in the ZF5HP24 pressure regulator valve bore. Wear at the inner portion of the bore causes high pressure spikes leading to broken drums, pistons or other parts, as well as restrictingconverter/lubrication flow.

Wear at the spring end of the bore allowsline pressure to exhaust resulting in low line pressure, soft shifts and burntclutches.
The Sonnax oversized pressure regulatorvalve kit 139740-01K restores valve-to-bore clearances so the pressureregulator valve can maintain correct pressures."

http://www.sonnax.com/system/announcement/139740-01K.pdf
Maybe a cheaper fix ?????

Jim Lombardi

 

Jim, that is very interesting. I wonder if anybody has done this, or if there is a write-up somewhere. For 40 bucks or so, I would consider doing it as a preventative measure. I've been lucky, 120K and still the original tranny. Every time I touch that shifter I gingerly wait for the tranny to engage before I touch the accelerator. I also keep it in "sport" mode all the time.

 

Sonnax - Aftermarket replacement transmission, torque converter, and high performance automotive parts

This is the Sonnax page for the oversize valve, reamer, etc.

 

This is not the first time that ZF gearbox designs have had valving problems in the valve block, causing uncontrolled internal hydraulic 'leaks' that damage other parts of the gearbox.

Way back in the mid 1980's, the old 4-speed electrohydraulic 4HP22EH transmissions fitted to BMW's had problems with the forward clutch drum (again) failing. This was traced to fluid leakage past worn valving, which would partially energise the forward clutch pack when the gear selector lever was in 'P' or 'N'.

This would eventually burn out the clutch plate pack, as they are meant to be either fully 'on' (engaged) or fully 'off' (disengaged). If they are only partially engaged, they slip & burn out pretty quickly.

The fault would manifest itself after long periods of engine idling in 'P' or 'N', as the partially engaged clutch plates would burn out & then when 'D' was selected there would be no drive.

Amongst the poorer members of the BMW fraternity who could not afford a full gearbox overhaul, the accepted method of living with this fault was to make sure the gearbox was always kept in 'D' at traffic lights or with the engine idling. The fault would become noticeable as you could rev the engine in 'N' & the back would sink as the car would try to move forward with the light torque transmitted through the partially engaged gearbox clutch plates with the selector level in Neutral.

I had an old E28 BMW 535i which had had the gearbox rebuilt by the previous owner after it had failed with no drive. I used to notice this residual 'creeping' in 'N' & when I learned about the fault, I always kept the gearbox in 'D' when the engine was running, so the forward clutch plates were fully engaged with no slipping & the gearbox never failed.

The fault was again due to worn valving, and ZF modified the valving in later gearboxes around the late 1980's to reduce this fluid seepage-but the previous owner of my car must have been unaware of this 'root cause' & simply had the gearbox rebuilt with a new forward clutch, leaving the original worn valving in place to potentially cause the fault all over again...

Yet once again the poor old forward clutch took the beating & failed, when the root cause was actually in the valve block body.

ZF autobox fluid pumps pressurise the fluid to a 'master' pressure of around 25 Bars, so any wear in the valving at that pressure will allow leakage past worn valving & bores, which then goes on to damage other parts of the gearbox.

This was known way back in the late 1980's on ZF gearbox designs...

 

Sonnax is the go-to for VW autos with valve body problems and they have ALOT

(especially the 01M)

 

Hi Jim, you are a real help as usually! Today I searched the old thread and I thought that if you already had business with Eriksson, maybe you have a link or something for the rebuilt unit, which pistons are included as there are 4-5 I think. I will be ready to pay 250 $ just to prevent the failure of the gearbox, but maybe someone form the States is more open to try this and to make a tutorial.
My only question would be if changing this will prevent the A drum breaking, where are all the "tech certified" forumers when you need some advice?

 

From the perspective of BMW's fitted with ZF autoboxes, once the valve block problem had been fixed then the gearbox was usually safe from destruction.

You pays your money & takes your choice...

Doing nothing will leave the gearbox wide open to failure-whereas having the valve block properly overhauled will stop the 'root cause' of the problem.

Of course, the transmission could still fail due to old age & normal wear & tear-there are no guarantees with an old, high-mileage gearbox.

But since the valve block can be easily accessed with the gearbox sump removed, then it's worthwhile having a gearbox fluid & filter change done at the same time as the sump is removed to reach the valve block. That way you cut down on the labour charges as the 3 jobs of filter replacement, valve block overhaul & new fluid can all be done in 1 go with the sump pan removed...

 

What gearbox is in it?

 

Flay
I found 4 different rebuilders that sell Jaguar ZF5HP24 remanufactured valve bodies
Maaco price is $880 and sunbelt priced at $450 and Trans Specialities at $295 and WIT (Whatever it takes) at $330.

Here are the 4 webpage links:

Transmission Valve body 5HP24 , 95-E98 , BMW/Jaguar -Stamp # 0501-209-875 P139740-3

Sunbelt Valve Body Builders - Re-manufactured bodies; 01M, AW 55/50 bodies and linear solenoids, 09G, and Saturn TAAT Units.

TRANS SPECIALTIES : JAGUAR ZF4HP24 VALVE BODY Remanufactured and rebuilt automatic transmissions, transmission parts and torque converters

https://www.wittrans.com/showfilter....65&Section=169

I called Valve body pro, but they said that they only sell to dealers and repair shops.

I am even not sure if any of the above sell these to the general public.

It appears that these rebuids are complete assemblies incudling all the solenoids.

I will try to call Eriksonn early next week to see if they sell rebuilt valve bodies.

Jim Lombardi

 

Thank you Jim,I was trying to simulate the acquisition on the cheapest seller site and it it was OK until the address request, so probably they sell to the public.
I checked on the bimmerforum and they talked about this valve body changing as preventive measure.
I don't have an account there to search for more.

It would be a good business for all of us to prevent our boxes breaking using this method, but I think it needs a little more detailed study.