D2 TD5 Autobox diagnosis

[steve_a]

Attached is a nanocom capture from my drive home from work.
The period of time of interest is from about 4:12 to 6:19 where you can see the revs gradually rise while output and turbine speeds remain the same.
The symptom in the car is that at about 60km the revs gradually shuffled up to 2900ish and then the box did an attempt to do some kind of change (I think up, but not sure).
As it happened I then stopped for the traffic lights, and it doesn't occur.
This is pretty much reproducible when leaving work in the evenings, as you can see the route means that I set off and tend not to stop.
I have a similar capture of the morning that I will look at next, but it never occurs when leaving the house, but then I stop and start a few times in those first 10 mins.

The box has probably had a hard life, I think it was towing for a while (brake controller was fitted and service history lists a failure and some work about 2 years ago), on top of this I had the front cooler hose airing the oil, causing slip and overheat, before finally giving way and driving with a bare minimum of oil for 30km to get to a roadhouse.
On the plus side it has had lots of new fluid..., I flushed the cooler a few weeks ago and I did the filter as well before the pipe failure.

What I am trying to figure out is where to go with the box:
1/ Replace torque converter and see if this fixes it
2/ rebuild box locally (maybe the ZF guys)
3/ rebuild and new torque converter
4/ new ashcrofts box & torque converter.

I am hedging towards 4 since I trust Dave back in the UK a lot and I'd rather spend a bit extra and be sure of the product.

Anyone got any ideas from looking at the data?

Timeline:
0:00 - 3:00 leave parking, roundabout, merge main road
3:00 - 7:00 main road doing about 60km, revs rise, gear shift bumps, then stop for lights
7:00 - 11:00 local roads
11:00 - 18:00 90km expressway
18:00 - 20:00 local roads
20:00 - 23:00 80km road
23:00 - 25:00 local roads
25:00 - 27:00 80km (ish) up hill, full throttle locked third.
27:00 - end local roads

92580

[sierrafery]

why dont you run a stall test on it?..., it might point you in the right direction, see attachment here http://www.aulro.com/afvb/2308855-post3.html

[steve_a]

Already done, stalls out at 2800 to 2900, this hasn't changed even with all the work done. So not exactly conclusive.
Attached is the engine capture from the run home this evening, more or less same timings and more or less same behaviour.
Didn't get caught by the lights so I had to bugger about a bit to get the revs to drop back from 3000.

Also had the other thing happen, which is that it doesn't seem to lock the torque converter up on the expressway at 90kph, so sat at about 3000 (but not slipping, just won't lock up).
I've seen this a lot before we fixed the cooler pipe, first time since then. I had to mess about and in the end kicking down caused it to enter lock up after accelerator was released.

Do these D2 boxes have a governor on them? I've always suspected it's this sticking and not letting enough pressure in, moving through revs etc means that it gets a work out and frees up.

[sierrafery]

AFAIK only the non electronic ones have the governor, on these with ECU there is a output shaft speed sensor which can make you that trick i mean to give wrong readings which might not trigger a fault code, according to the fault code list it's not even covered by diagnostics, or even if it is i'm sure it's only for open/short circuit as IMO that EAT ECU is quite rudimentary in this area

An output shaft speed sensor in the gearbox housing outputs a signal to the EAT ECU. The EAT ECU compares
output shaft speed with engine speed to determine the engaged gear, and output shaft speed with vehicle speed to
confirm the range selected on the transfer box.

[PhilipA]

Maybe I am dumb, but I cannot work out anything from the graphs.

One thing to remember is that the transmission will not lock until the engine temp is AFAIK at least 76C, so the early part of your trace is not relevant to checking lockup. It will not lock in 3rd or 4th so when you start along an expressway it will rev up to 2800RPM depending on the hill.

My trans will lock in 3rd at 70Kmh with any throttle ( and stay locked down to 60Kmh) and I am pretty sure will lock at a lower speed>60KMH on trailing throttle.
The trans will lock in 4th at >80KMh and stay locked down to 70KMh on light(ish) throttle.

It sounds to me that your first change was locking in 3rd then unlocking as you went under 60Kmh to stop at lights.

IMHO to check operation you need to get a level stretch and check locking by accelerating uninterrupted up through 80KMH and note locking in 3 then to unlocked 4 then to locked 4. The engine must be thoroughly warm .

I must say it does seem strange at first experience if you accelerate hard from a standstill as the trans will go 1-2-3 unlocked , 3 locked at 70+ ( revs down) , 4 unlocked until 80+ ( with revs rise from 3 locked ) then 4 locked.
It takes a few seconds for the trans to lock after each change .
Regards Philip A

[slug_burner]

The only thing I can see is a engine speed rise in the very first part of both traces. But as it occurs early it is consistent with the engine not yet up to temperature. Agree with Phil.

[Pippin]

Maybe I am dumb, but I cannot work out anything from the graphs.

One thing to remember is that the transmission will not lock until the engine temp is AFAIK at least 76C, so the early part of your trace is not relevant to checking lockup. It will not lock in 3rd or 4th so when you start along an expressway it will rev up to 2800RPM depending on the hill.

My trans will lock in 3rd at 70Kmh with any throttle ( and stay locked down to 60Kmh) and I am pretty sure will lock at a lower speed>60KMH on trailing throttle.
The trans will lock in 4th at >80KMh and stay locked down to 70KMh on light(ish) throttle.

It sounds to me that your first change was locking in 3rd then unlocking as you went under 60Kmh to stop at lights.

IMHO to check operation you need to get a level stretch and check locking by accelerating uninterrupted up through 80KMH and note locking in 3 then to unlocked 4 then to locked 4. The engine must be thoroughly warm .

I must say it does seem strange at first experience if you accelerate hard from a standstill as the trans will go 1-2-3 unlocked , 3 locked at 70+ ( revs down) , 4 unlocked until 80+ ( with revs rise from 3 locked ) then 4 locked.
It takes a few seconds for the trans to lock after each change .
Regards Philip A


I beg to differ but if you pull away from standstill in "Drive" the trans goes 1-2-3-4 unlocked until 80+ then locked. It only locks in third when third is selected rather than Drive.

[discorevy]

I beg to differ but if you pull away from standstill in "Drive" the trans goes 1-2-3-4 unlocked until 80+ then locked. It only locks in third when third is selected rather than Drive.

Agreed , while this is the normal operation , there is a modification that can be done with the separator plate in the valve body to make it happen as PhilipA describes , 99.9% of auto d2's run as Pippin describes

[PhilipA]

I beg to differ but if you pull away from standstill in "Drive" the trans goes 1-2-3-4 unlocked until 80+ then locked.

You are probably correct as I usually drive around in 3 when towing at under 80Kmh to lock the trans, as the revs are usually lower in 3 locked than D unlocked and of course the trans will run cooler.

It may be that I have entered expressways in 3 then changed to 4 at under 80Kmh thus causing the up down rev situation.

Regards Philip A

[steve_a]

Yea, I don't think you really understand what the chart shows, here is the slice of interest, where red is engine revs, green turbine speed, purple output speed, blue throttle position.
Note that throttle, turbine and road speed (output speed) remain stablish, while the revs rise to about 2900.
This isn't about the lock up issue, that is separate, but related.
I guess making it slightly harder for you is that my macro to convert the solenoid and wxyz values to selected and engaged gear is missing, but at that stage it is drive and 4th, no lock.

I don't have the autobox diag from the run when it refused to lock up on the expressway, you can record engine or gearbox, but not both which is a bit of a pain.

You *may* see the car lock in 3rd even in drive under a few circumstances, the most likely is under load, usually where the box kicks down from 4th (with or without lock) into 3rd without lock and then locks 3rd, under no load I've seen 3rd lock on change down, not sure I've seen it under load.
You may also see it go 1-2-3-3L-4-4L if you are accelerating gently enough that it can sit in 3rd for the right amount of time with the right throttle position, but it would be the longest, slowest acceleration profile ever...

In normal operation, you'd see 1-2-3-4-4L, so at 60km you are going to sit at about 2000rpm in 4th.

The expressway lock up issue is tied to if I have a clear run from start up, if I stop a time or two before hitting it then it will lock up, so it's not engine temp related as far as I can see, in fact if you look at the coolant temp (chart6-frm_wrke.xlsx) you can see that during the 60kmh slip the temp is about 70c and on the expressway already up at 88c.

Again, if I currently had to point at things it would be lack of hydraulic pressure (seals, governor, crap on the solenoid seals, pump) or clutch slip.

[PhilipA]

Is this on a level road or up a hill.
If up a hill it is normal if unlocked as the stall speed of the TC is 2800-2900 RPM.
All other things can remain constant.

If on the flat it would be very unusual., but it is likely be Torque Converter related.

My experience with Trimatics and others suggests that anything that is related to oil pressure in the trans itself will cause it to change back a gear or more just cruising along. If the clutches are gone I would expect it to Flare on changes . Another test is the time taken for the trans to engage when shifted from D to R. A long time is bad.
Although these tests refer to old transmissions the principles of autos are pretty standard. Just these days with fancy electronics they can engage 2 or more ratios at once, thus giving say 6 speeds or more from an actual 4 speed set of gears .
Regards Philip A

[Rok_Dr]

I wouldn't rule temperature out just yet. Plotting the temp fields against speed fields and manifold turbo pressure, shows that the pattern you are concerned about occurs during the warm-up period and disappears once once the coolant temp (Brown line) has stabilized. (Note Y axis is logged and gaps in road speed are zero values).

https://www.aulro.com/afvb/images/imported/2015/04/887.jpg

I'm not full bottle on Auto transmissions or Turbos, but could it possibly be engine related or and an electrical comm issue rather than transmission???

Another idea is to log the data over the same route with the engine warmed up first.

Cheers

Steve

[steve_a]

Pretty level, no discernable gradient.
I can't imagine getting the test without being in the warm up stage to some extent, just idling would take forever to get there.
There is a chicken and egg as well on some of that, if you replicate the revs, say go for a drive and keep it in second (I reckon that would give you 3000 for 60kmh) then the engine will be heating up.
I can actully stop this from happenning by just stopping and letting it work through the gears again, or by manuually changing to force a bit more action in the box.
I reckon I might try and ping Dave or his son over on LR4X4 to see if he has a definitive diagnosis.

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[slug_burner]

steve_a,

Is Rok_Dr's plots and analysis fair and consistent with your experience? That points to engine temp determining if the gearbox should go into lock or not. What other diagnosis are you looking for?

[steve_a]

steve_a,

Is Rok_Dr's plots and analysis fair and consistent with your experience? That points to engine temp determining if the gearbox should go into lock or not. What other diagnosis are you looking for?

Not really, the period of time/speed is not when lock is expected and I wasn't looking for it to lock, it's only 60kmh. I made a point on the way home last night of running the car is the first few seconds to a higher rpm in 1,2,3 and also coming to virtually a complete stop.
The same stretch then saw it behave and do the expected 2000rpm after that even though the engine would have been at the same temp.
This just points to hydraulic pressure to me, so crap in the solenoid seals or similar.
It may be that there is more than one issue, e.g. poor oil pump, worn clutches which makes a diagnosis tricky due to interactions.

Electrical issues are tricky, if it only happened in the wet say then I'd be thinking that maybe it is a loom issue, but nothing is pointing me that way at the moment.
Engine issue, not this fault, though I do wonder if it is putting out 100% power, my tuned-up-a-bit 300tdi would seem to give it a good run for it's money, till it runs out of gearbox :)


I was hoping (as in first post) that someone knew which area(s) of the box were the likely cause so I could see if triage or full fix was the way to go.

[steve_a]

For once the Rover was helpful and did the same thing on the way in to work on the same stretch as out. Not as pronounced, but was accompanied by a surgeing feeling, it was like clutch slip in a manual but was oscillating.
Also accompanied by ATF smell. On checking, it had spat some fluid out of the dipstick (I added one a few months back).
Level is about right and the dipstick is the only source of ATF I can see.

So, more evidence for hydro but no idea of actual cause...

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[PhilipA]

On the plus side it has had lots of new fluid..., I flushed the cooler a few weeks ago and I did the filter as well before the pipe failure.

I am wondering if you have crushed/misplaced the o rings that connect the filter to the valve body and it is leaking. Spitting up the filler tube suggests that the fluid is getting back into the sump but not being sucked out.

It may be worth a look before you go spending big money.

I think you would have more than one symptom like flaring changes, slow engagement, etc if there was something mechanically wrong. Sometimes the best course of action is to relook at things you have recently touched.
Regards Philip A

[steve_a]

Not a bad thought, but I have done nearly 10k km since I replaced the filter, and that should exhibit an issue all the time in terms of lack of drive because of no pick up.

I still have my hose clamp fixed front cooler pipe, but I'd more expect that to cause aeration or some other issue once warm.

I noticed on the way home that 3rd gives 2100rpm for 60kmh, while 4th gives at best 1800, and often closer to the 2100. Having given up with 4th (unlocked) on the way back it seemed a bit happier, so I'm wondering, not surprising, if 4th is toasted.

There are a bunch of other symptoms, sometimes it doesn't pick up drive from stationary, though once that was definitely fluid level, harsh downshifts (audible clunk as you slow down and the gear engages), I happened to shift straight from D to R the other night and it seemed to take an age to engage.
I swear that pushed hard there is a 'roaring'/whoosing noise as well, almost like the torque converter is pumping heaps of oil for little effect.

To me the take up for drive doesn't and hasn't ever felt right, with a noticable lag as your rev up (like 0.5 second lag from foot down to motion, even though revs rise during the time), makes it feel very sluggish till at least 2500.

On the soft sand at Lake Bonney at easter I noticed that it just didn't drive like I expected, I thought I was losing traction, only to look out and find that nothing was going yet.. despite low range locked.

If only I could have got the manual.. but the missus wants the auto...