I had a board member and IIDTool user PM me with a series of faults he had on his RR. His questions and my reply is below. Does anyone have any additional input?

Hi Steve
Following a Transmission Fail Safe Mode message I have got a :

3B Stall speed fault: general fault

8D Instrument Pack Transmission Interface Bus Fault

59 Transmission Fault emergency program

I have a 2002 L322 Range Rover with the 4.4 V8 petrol Vogue

I have changed fluid and filter.

The Fail Safe only comes up after about 10 minutes driving when everything warms up prior to that it drives normally. We have an ambient temperature of around 32 degrees C.

reply

Hi
None of us are experts in the ZF transmission but there are some common faults:
- the transmission cooler is known to clog. Check the lines after the transmission has warmed up. One should be warm and the other (obviously) somewhat cooler. One or both stone cold is a problem.
- when the vehicle's voltage is not adequate, the transmission is amongst the first systems to throw faults. Turn on the lights, demisters, fans, etc. and check the voltage across the battery terminals and also with the + probe on the - (neg!) battery terminal and the - probe grounded on the boda and then on the engine somewhere (make sure the surface is clean and you have very good contact; scratch with a screwdriver). Across the terminals you should see around 14.5V but no less than 14.2V with the engine running and with the - probe on the body and engine not more than 100mV or so.

What I do not really understand is 8D Instrument Pack Transmission Interface Bus Fault . Do you get this every time you have a failsafe message?

I am going to take the liberty of posting your question in the forum. There are some members (above all RRPhil) who know their way around the ZF transmission extremely well.

In the future we will have a wiki where fault codes/fixes can be posted.

regards,  
RRC 2Dr, RRC 4Dr,
P38, and 2 L322s
(wife thinks I'm nuts - prob right, too)

Hi Steve,

Coincidentally I had someone contact me recently who has a 2002 4.4 which keeps displaying TRANS FAILSAFE PROG and, when he ran diagnostics on the vehicle, it produced the same ‘stall speed’ & ‘059’ faults. He’s bringing me his transmission for rebuild this afternoon so I should know if there’s a mechanical or hydraulic explanation in the next couple of days, once I get the thing apart. Curious thing is, I can’t see the equivalent ‘stall speed’ fault code in RAVE for Testbook/T4.

Do you know what happens to your customer’s transmission when it goes into failsafe? i.e. does it engage 4th gear (limp-home) or does it sound like it has selected neutral and lose all drive with the engine revving freely?

Temperature dependency always screams ‘hydraulic leakage/seal problem’ to me.

Phil

Hi Phil

I am the owner of this vehicle and thank you and Steve for your consideration of the problem. I have read all of your posts and diagnoses on this and rangerovers forums and am hoping that it is an electrical problem not requiring full rebuild. Having said that I am prepared to spend the money if necessary.

So some more information to help you get the full picture. The vehicle has done 245,000 kms roughly 145,000 miles. I have had the car for around four months. The first time that I drove it was for 2500 miles from where I bought it to where I live and so I got to know it well quickly.

It had been performing faultlessly until the first time that it went into Transmission Failsafe mode. It was not a gradual proces of deterioration in transmission performance or an intermittent fault.

I drained the fluid and changed the filter hoping that that may assist with the problem but no joy. The transmission fluid was not burnt and although a bit dark was still not what you would describe as black.

History according to receipts show that it had a new convertor around 40,000kms ago or 24,000 miles and has had several new transmission coolers over time and a new radiator not that long ago.

There were no bits and pieces in the pan but there was some gray sludge on the magnets.

Symptoms on driving now are that after warming up it does go into 4th gear and stays there and will not work in sportshift mode. If I stop and go into Park or Neutral and then engage Drive it will rev freely on acceleration without engagement and then engages Drive with a thump. The same symptoms are present in Low Range and Reverse works fine.

I bought the IID Tool to assist with diagnosis after reading all the posts on this great forum rather than just taking it to a dealer. Others experience on here indicates that the response would be "new transmission required"

So the faults are 3B stall speed; 8D Transmission interface bus fault and 59 Transmission fault emergency program and prior to initial clearing of faults on first reading there was 34 Gear monitor 4 and 38 Controlled load transfer fault.

Very interested to hear your interpretation and the results of the teardown on the transmission you are currently working on.

Regards


Michael

To be honest Michael yours does sound like the ‘classic’ A-clutch leakage issue caused by a split O-ring due to failure of the axial needle bearing between the B-clutch hub and the C-clutch drum.

Click image to enlarge

Click image to enlarge

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Thanks for your assessment Phil. Having read many of your posts on transmissions with similar symptoms I thought as much. However with the high cost of getting a transmission reconditioned we always live in hope.

Time for me to start getting quotes at least there are two transmission specialists here who do ZF boxes.

Appreciate if you will post the result of your current pulldown to see if it is similar to your prediction on my one with the same codes.

regards

Michael 2002 L322 4.4 V8 Vogue

Phil

I am wondering if you have finished that teardown of the transmission that you mentioned above and what you found with those similar fault codes to mine. Any feedback available as yet?


Michael 2002 L322 4.4 V8 Vogue

Hi Michael,

Yes I’m around 80% the way through stripping down all the sub-assemblies now. I’m currently working on the valve block and, by tomorrow, I should know if the problem lies there.

The transmission I’m working on certainly hadn’t suffered from the bearing and subsequent O-ring failure but the owner’s symptoms were quite different to yours (though the DTCs were the same). His failsafe warnings started the moment the engine fired up from cold and the transmission would drop into neutral with no drive.

From what I’ve seen so far I still don’t have an explanation for his issue and I’m not sure that I’m actually going to find one i.e. a mechanical or hydraulic fault. If not, then the fault is either electrical or electronic. The only thing I’ve turned up so far is that the A-clutch friction plates are wearing and the steel plates have a lot of heat spots – clearly the clutch has been slipping under load.

Out of the last (say) dozen 5HP24s that I’ve rebuilt, three of them had nothing whatsoever internally wrong with them – the problems lay elsewhere (wiring, transfer box motor, etc.) but, unless you teardown the transmission to check, it’s often not possible to diagnose the fault from the DTCs.

It seems to me that though the vast majority of the diagnostic codes given out by the transmission ECU relate to particular ‘physical’ faults with either the eight solenoids (open circuit, short circuit, etc.), the speed & temperature sensors or the inhibitor switch - which is all fine and very useful - the remaining ones are somewhat ‘woolly’ interpretations of what might be happening as a result of some speed signals that don’t quite add up e.g. due to a clutch slipping.

I guess this is a question for Steve, but presumably you can only report back the set error codes that are issued by the ECU and cannot gain any further information about the fault e.g. which particular measurement or calculation caused it to be triggered?

For example, I wonder how many people have needlessly replaced their transmission output speed sensor as a result of the ‘standard’ P0720 DTC issued when the transfer box shift motor potentiometer malfunctions and flags ‘output speed sensor fault’. What it actually means is that the signal from the speed sensor wasn’t what the ECU was expecting for that particular condition. The problem is that the DTCs are only as good as the control system designers that had to decide what the likely failure modes in the transmission were going to be.

Sorry, that turned into a bit of a rant didn’t it

Anyway, I’ll report back on progress with my current transmission rebuild when (if?) I find something.

Phil

Hi, I just joined because I seem to be having the same problem. I haven't had any codes read yet but when the engine is cool all is well but once it warms up it has a problem shifting into first gear. It hits it with a thud. All other gears are good. I just had the transmission filter and fluid changed the day before it started happening though, I put in the Valvoline Max Life that says it works for LT1171 so I am wondering if this is a coincidence or if maybe that fluid is not any good in this transmission. After scouring I found some people who say the green label transmissions must have the yellow fluid which I have now ordered. I have a hard time believing its the transmission because ZF transmissions are incredible and I've never seen a bad one.

If you are certain these symptoms indicate the ‘classic’ A-clutch leakage issue caused by a split O-ring due to failure of the axial needle bearing between the B-clutch hub and the C-clutch drum, how deep will I have to dive into the transmission to replace these parts? Is it a complete teardown or what?

Thanks for the info!
John

Seems a heck of a coincidence that the problem started immediately after the fluid & filter were changed. Did the shop doing the work definitely know that the engine had to be running when the fluid level is set, otherwise the transmission will be under-filled? You should only use Mobil ATF LT71141 / ZF Lifeguard Fluid 5 in your 5HP24 (and a genuine Filtran filter)

Phil

Yeah, I know. Im definitely on board with this issue being a viscosity issue. Once the fluid gets hot it is causing a problem in the transmission. I'm hoping the valvoline max life is not staying at the same viscosity as the official stuff so thats where Im going to start. I'm not buying a fault in the transmission yet. I don't believe ZF transmissions fail unless there is a problem outside affecting them. I read about the overheating issue with the radiator and I read that enough times the sensor won't pick up the fault. If thats the case then the codes that do get thrown are probably irrelevant since the transmission will think the gears are failing, things are slipping, etc all due to extremely high viscosity. What I read is it takes 25 minutes for the transmission to begin to overheat from cold so I drove mine last night until the engine reached full running temperature and it was still shifting seamlessly. I decided a few minutes later to take it home and not deliberately overheat it. The crack in the valve body (or where ever it is exactly) also spells out a result of extreme heat to me. Whats the best way to measure the temperature of the tranny? A laser gun?
Thats where I'm starting. I'll question German engineering last.

When you guys say your transmissions begin to slip when the car warms up how do you define warmed up? When the temperature needle hits 12 o'clock or 25 minutes into driving or what? Like I said, mine was warmed up. Needle was at 12 o'clock and it still shifted fine. Not sure how warm the tranny is at that point but its supposed to be overheating in 25 if theres a cooling issue

This is the cheapest place I found for the "official" ZF fluid. Its a 6 pack for 88 bucks. Is there anyplace cheaper?

http://www.thectsc.com/products/zf-lifegua...14-57.html

I read a lot of cofused messages about whether or not peoples transmissions are overheating. I don't know if its posted somewhere but it would be a good idea to establish what is normal operating temperature of a range rover. I read online a transmission shouldn't go above 220. I'm going to buy a laser gun from harbor freight and see how hot mine gets idling on the driveway first. I think a laser gun would be a reliable method of testing the temperature right? Maybe shoot it from different places and the cooler lines also... It would save time instead of speculating and pulling parts unnecessarily.

As I suspected, I let my range rover idle in the driveway for half an hour and reved it for a couple of minutes at 2500 rpm (literally a couple of minutes) and while the engine surface temperature was around 180 the transmission was 220 and went as high as 240. The coolant lines feeding the transmission were 167 both. Apparently blocked to be reading the same temperature? This is merely idling in the driveway. No codes. No warning. Nothing. I didn't think the ZF fails since I used to redo discovery 2's and resell them. Never once did I ever come across a bad ZF transmssion. As for the failed parts inside these transmissions I would say they are due to the sensor not registering the overheating issue and people continuing to drive them. Get on the freeway with an overheating transmission and its going to crack, and O rings will burn. Looks like Im in the market for a new radiator, right? I recommend the 35.00 temperature gun at harbor freight as a first check. Forget codes until the temperature is tested.

Actually no, I'd say the first place to start is the coolant lines. For them to be at 167 both going in and out may indicate a blockage. The myth behind doing a complete transmission flush and your transmission going to pieces isn't a myth. What happens is you brake down the sludge too quickly and the sludge blocks up the transmission and its lines. Since I had the wrong filter when I did the first flush I did it again once I got the correct filter. I doubt these radiators are prone to failure also but they could be. The place to really start though is to get the coolant lines blown out and make sure they aren't sludged up. For both to have the same temperature I am imagining a small amount of fluid slowly creeping through. To avoid sludge and blockage its best to regularly change your transmission fluid every 50,000 miles.