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After the dreaded failure of the gearbox in my 1996 XK8, I decided to have a go at repairing it myself. The problem turned out to be the classic ‘A Drum’ failure. To fix this, I replaced the drum, but also did a general reconditioning to reduce the need to do all this again.
There’s plenty online to advise the budding amateur, but I thought I’d share some lessons to help anyone else considering this.
1. ZF have a repair manual free available online. In reading it, don’t be put off by all the specialist tools that are used. I did not need a single specialist tool to do the job. It just takes a little longer. http://www.jagrepair.com/images/Auto...r%20Manual.pdf
2. I found YouTube videos far more useful than the ZF manual. My new best friend became a guy called Gary Ferraro. His channel has ‘teardowns’ of ZF 5HP24 from Jaguars, a Land Rover and BMW X5. All useful. Research these so that you know exactly what to expect when stripping down the gearbox. There is a video where he also partially re-assembles one. Useful.
3. There is a poorer quality YouTube video of an XJ8 ‘box being rebuilt. It’s quite detailed and worth a look. However, there is a point where they state that they had to make a tool to lower rebuilt parts back into the ‘box. You don’t need this tool if you reassemble it vertically rather than horizontally on a bench. Here’s a link to the first of 9 videos:
4. It sounds obvious, but the ZF 5HP24 was fitted in several cars, so don’t limit your internet search to “XK8 transmission”. There’s a wealth of advice and images on other forums. I used forums for Ranger Rover, BMW and Audi.
5. Another obvious point, but this whole project looks daunting if you don’t break it down into mini-projects. Discipline yourself to recondition only one clutch at a time. That way, you don’t lose track of the rebuild.
6. I found the following faults: The A Drum had split. An O-ring on the A/B clutch had torn.
7. To recondition the gearbox, I bought the following – listed in order of importance:
• 'A' Clutch Drum (This A clutch drum replaces the blown one and - so I hear - is an upgraded part to reduce the chances of the fault reoccurring)
• TransGo 5HP-24-PR Pressure Regulator Valve Repair Kit (The story goes that the 'A' Clutch Drum fails because of a surge in pressure caused by this valve wearing. Mine looked fine, but a worn one won't be that easy to see. So I had this valve imported all the way from US America.)
• Overhaul Kit Genuine ZF OE (Contains dozens and dozens of O-rings, scarf rings, etc. All are packed in separate packs so that you can work your way through the gearbox in a logical order)
• Friction Kit Exedy (These are the clutch rings. Mine looked fine, but with a blown A drum, clutch rings can become contaminated with embedded metal fragments, so I changed them.)
• Bearing Case A/C (there is a needle bearing between clutch A and clutch C that has a habit of failing. Mine looked fine, but I changed it for the sake of £10.
• F Piston (This F clutch piston can fail, resulting in a loss of reverse gear. Again, mine looked okay, but I bought this in anyway)
• Filter
• 10 Litre of Mobil Esso LT71141 ATF Automatic Transmission Fluid
• Blue Goo (Proper transmission assembly gel. Worth buying as it's so much better than vasoline or standard grease. It prevents damage during assembly and seats all O-rings and seals properly)
8. Most of the parts were bought from one-stop-gearbox-shop on eBay.
9. The Exedy Friction Kit I bought contained one clutch ring too many. This panicked the hell out of me at the time, as I thought I’d failed to fit all of them. I revisited all the work I’d done to confirm I hadn’t made a mistake. Perhaps this was a one-off error with the friction kit I bought, but if not, don’t worry about it.
10. Don’t skimp on parts. Some people just replace the ‘blown’ A Drum. Trouble is, when is blew, where did all those little shards of metal go? I probably spent a few hundred pounds to replace parts that I could have just reused, but all the time and effort of researching and doing this work is so great that I’d never entertain the idea of just changing the A Drum.
11. The most awkward bit of the job is compressing the circular springs that hold the clutch packs in place. You’ll need to take your time to improvise tools for this. ZF has special tools, but I found that using G-clamps, inverted pullers and the like worked just as well.
12. I found that nuts and bolts freed off quite easily, with exception of…
13. …There are two oil cooler pipes that must be removed. I think that they are aluminium going into steel. Either way, mine were corroded in tight. After much effort, one was undone but it wrecked the pipe. The other required the gearbox casing to be sent away for drilling and a new thread cutting in. Not cheap and really delayed progress. Of course, both pipes needed to be replaced too.
14. If you do need to replace the oil cooler pipes, avoid second hand ones.
There is a small bracket behind the air con compressor that holds the pipes in place. This is a recipe for localised corrosion on a pipe that can otherwise look good. One of the second hand pipes I bought leaked. I ended up buying new from Jaguar. Double the price but worth it. I then wrapped the bracket in plastic tape to prevent future corrosion.
Of note, my gearbox failed at 122,000 miles. This is despite servicing the gearbox at 120,000 miles. So, sadly, servicing is no guarantee against failure – particularly when it’s done as belatedly as mine.
Ask as my 96 tranny failed last year paid £200 for one from a breakers and paid £600 to have it fitted by a jaguar specialist, so £800 in total. Plus I had 10l of LT71141 in the garage (bought from a forum member that upgraded to a XKR)
My cap (if I wore one) would be doffed as not a job I'd attempt....my skills are limited to oil & filter changes
hello
Thank you for sharing all that precious info !
ive learnt so much.
Have you guys heard of SHELL Spirax atf sx s2 and is it adequate to use on our zf 5hp24 gearboxes ?
im planning to follow the 'old 1 liter out' ' new 1 liter in' technique via gbox coolant line to try and clear my transmission problems. ( gearbox fault on dash now and again) happening more and more thus limpmode.
thanks in advance
Where can I get needle bearings as I intend to rebuild gearbox? I also plan to change the valve. Any guidance on buying these parts would be appreciated.
I have new c clutch drum although nothing wrong with my 2002. New steels and frictions A/C clutch. Seal kit with gaskets.
Is it advisable to change all friction plates and steels?
I think If I had attempted this I would have ended up fixing a shaft to each door and hitching up to a suitable horse, hence reducing in power to 1hp. One thing is for sure: my Jaguar would never have been able to push itself along again.
Hi, It’s been a few years now, but the eBay store that I purchased the majority of parts from looks to still be in business. Below is a link to all 5HP24 items currently in stock – note that many items have ‘Audi’ or ‘BMW’ in the description, but it’s the same stuff:
Regarding the needle bearing, I paid around £10 for mine, so am staggered at the cost increase of the one linked to below. My only suggestion would be to get the product information from this listing and search further afield for a competitive price:
The valve upgrade is made by TransGo. I bought it on eBay but had to have it imported, I think, from the USA. None are listed on the UK eBay site, but several are listed in the US. Here’s an example:
Regarding friction plates, I changed mine for no other reason than:
1) there might have been metal debris embedded in the material following the gearbox failure. (In truth, I found very little evidence of this. From memory, there was some debris on a couple of the plates, but it was not embedded.)
2) They can get burnt with wear and age. (However, at 122k, mine weren’t.)
Nevertheless, I’d probably fork out for friction plates again if I had to do another, particularly if the car was a keeper. The peace of mind remains long after the additional expense is forgotten.
To answer another poster’s question, I spent just over £1000 pounds in parts, but I went ‘overboard’, so this figure shouldn’t put people off. Remember, I got stung with having to purchase extra cooler pipes, gearbox housing machining, and various other bits and bobs. You could reduce what I paid by about £300 at least; maybe a couple of hundred more again if reusing the clutch friction plates.
I doubt a quality repair can be achieved for less than £500 in parts. However, if a gearbox works okay, and you’re just looking at preventative upgrades, you’ll only need the TransGo valve kit, fluid, filter and perhaps a pan gasket (or make your own).
Of note: The XK8 is several thousand miles post the rebuild now. All is well (tempting fate?).
...and you would have no end of ongoing issues with the exhaust.(
I have just understood this!!
Clearly this means further thought. In addition to the aforementioned shafts welded to the doors, I am contemplating two alternatives. The first is to raise the suspension by, say, 12 inches in order to clear the exhaust emissions. The second is more attractive to me, and is to weld a snow plough to the front of the bonnet. This solution is the more appealing of the two.
For a thread 2 years old, this is technical gold dust and a good laught
Well,
andbark- thank you for following up on another forum member’s question. I too put in the Transgo PR valve purely as a preventative measure. Not sure what A Drum I have but the part is peanuts cost once you made the effort to get in there.
As for pulling the XK8 - towed by a horse, the brown exhaust deposits is one worry. Have you seen how much pee a horse does? Plus who’s steering in the car as he won’t have much of a view. LOL
It's been a few years since this thread was started, but I thought I'd add my experience to it.
I also decided to repair my own transmission when it failed, and found this thread to be a big inspiration.
A big thank you to the O/P.
I was 'lucky'? in that -
1, my trans failed at a fairly low mileage
2, when it failed it became undriveable quickly so I didn't make it worse by spreading the metal fragments around.
When I took it apart, the A clutch drum was really ripped up at the snap ring groove.
But that was all - there was no other damage apart from the A clutch drum and seals.
There were very few metal fragments in the working parts of the trans - it nearly all got caught in the oil filter & on the oil pan magnets.
So I didn't need to replace anything except - the A clutch drum & seals, Filter and oil.
However as a future precaution, I also fitted an input shaft seal and the Transgo PR valve replacement; and stripped and checked the valve body for metal bits and other damage, luckily there were none.
I only stripped the main part of the trans back to the E drum - because everything I took out (apart from the A drum) was in near perfect condition - there was no point going further.
I bought my (A drum only) seal kit and main oil filter from the local ZF trans specialist, who was a good guy and helpful. He said he's stripped a few of these in a similar way. If the diagnosis is probably just the A drum is bad, he doesn't strip it much further - as long as everything else looks good, and there are very few metal bits.
The A drum failure starts with metal fatigue at the snap ring groove. Small cracks start to appear at the corners of the stamped out grooves.
Then the cracks spread around and join up. Until the hydraulic pressure spike at gear engagement - is enough to rip the drum apart at this weak point.
(Not my photo - I didn't have a good enough close up of the damage)
This part is a useful idea for those in places where a replacement drum is expensive and/or hard to get. And may be more useful as the years go by, and parts are harder to find - I welded the A drum and re used it,
Now this welding is not pretty - I only had a stick welder at the time - but it is MUCH stronger than the original. (and maybe some bought replacements)
Compare the welded area with the damaged original. In the snap ring groove area, there are no grooves or cuts outs for cracks to be able to start at. It's now all solid metal and very much stronger.
By the way - this problem is not unique to this ZF trans - many others suffer from it.
Below is a picture of one from the internet, from a Ford F150.
Notice that it split at exactly the same weak point - the cracks spread from the edges of the pressed out segments of the snap ring groove then go all round. So welding either side of this weak area to the base cures this weakness.
My trans rebuilt, and ready to go back in........
I only had to buy a new seal kit for the A drum, plus oil & filter and a few welding rods and the Transgo valve.
So it was a cheap fix (in money but not effort....) Around $350 US / £250
Stripping and rebuilding it was not difficult - it was interesting and quite enjoyable.
But removing and refitting the trans from the car - on axle stands on the floor - really was not.....
It's been running well for about a year now.
Good luck if you do this - I recommend it, but it would be much easier with a hoist and trans jack.
I'm about ready to put my transmission back together, but lifting the assembly back into the case would sure be a lot easier with the "special tool" because the tolerances are such that it has to go in perfectly straight. On the countydomestic rebuild series on
he shows all the special tools he rigged up without giving enough details. It looks like just a long rod with a threaded end and the repair manual simply describes to "Screw lifting device 5x46 001 077 (fastened together with adapter 5w46 000 003)into tower I." I thought I'd order a threaded rod and make a bushing to center it but I don't know how access deep inside the shaft to measure the thread pitch. It's literally the length of that rod, maybe 12 inches deep, down inside the hollow shaft of the planetary drive.) Anybody know what that thread pitch is?
I didn't get any responses to my thread pitch question above so I "took a few guesses" and ordered three different sizes of threaded rod to try. And the winner is (drum roll please)..... M8 x 1.25mm!
10-26-2017, 07:05 PM
ZF 5HP24 Lessons Learned
