Auto Trans ECU Question

[carlosz]

disconecting the batt may not reset the lights but will reset adaptations because they are on the volatile memmory.. I suggested such to see if it comes out of limp mode, if a rover scanner is not available.
yup you were right, your old trans was on borrowed time.
great idea going stick, less chance of another catastrophy.
on severe cases (seen it twice) a maf will send trans in limp because it reads 4th gear slippage (it's a land rover thing) so it locks in to 3rd and extends the shifting point.
the wonders of obd 2 and land rover engineers.
hell on that note 96 to 98 discos and d90 gems obd2 used the same o2's front and rear while p38 used a separate part no front to rear.

 

[R_Lefebvre]

I could see how a messed up MAF might cause limp mode, but if you just unplug it, should solve that? I have driven with the MAF unplugged.

The R380 isn't perfect, but it's immune to this failure mode which is a particular problem in my area. ALL the trails are flooded. I wasn't going to put another ZF back in and just have this happen again. It would be inevitable.

 

[carlosz]

I could see how a messed up MAF might cause limp mode, but if you just unplug it, should solve that? I have driven with the MAF unplugged.

The R380 isn't perfect, but it's immune to this failure mode which is a particular problem in my area. ALL the trails are flooded. I wasn't going to put another ZF back in and just have this happen again. It would be inevitable.

I dont remember correctly which unit it was, but some time ago I had a customer who popped the clucth on his d 90 and snapped the trans output shaft, later in lr class I asked and found out there were 2 versions in the states and one was weaker than the other there is a simple way of telling them apart but for my life I cannot think of it

 

[Mongo]

Somethings cooked because the new maf didn't take it out of limp mode, which it should have when he swapped it out. Could be as simple as the tcm...drain the fluid and post up pic's of the fluid, it will tell us all if there was water ingress.

 

[R_Lefebvre]

I dont remember correctly which unit it was, but some time ago I had a customer who popped the clucth on his d 90 and snapped the trans output shaft, later in lr class I asked and found out there were 2 versions in the states and one was weaker than the other there is a simple way of telling them apart but for my life I cannot think of it

Probably a J suffix, which was subject to shearing across the oil feed holes in the output shaft.

I bought a new L suffix which is an upgraded unit from the J's and is stronger.

Still, any AWD car is likely to break something if the owner does a heavy clutch drop on pavement. Luckily, I soaked my clutch with oil from a leaking rear main seal, giving me just enough slip that I never have to worry about that. :banghead:

 

[carlosz]

Probably a J suffix, which was subject to shearing across the oil feed holes in the output shaft.

I bought a new L suffix which is an upgraded unit from the J's and is stronger.

Still, any AWD car is likely to break something if the owner does a heavy clutch drop on pavement. Luckily, I soaked my clutch with oil from a leaking rear main seal, giving me just enough slip that I never have to worry about that. :banghead:

yup all falls under the reposibility of the loose nut behind the steering wheel... lol
no offense.
I knew it was one but can't tell you 100 which one it was.
maybe even the lt77 but oh well it's water under the bridge im sure sometime I will be in that boat again and then I will hafta do my research proprely.

 

[ptschram]

Yes. I was an OEM engineer,


I now carry the electrical contact cleaner full-time. It's way better. Brake cleaner works too. That's what I used on the amp. Amp still works to this day.


It's all in the timing. Power must be removed from the device IMMEDIATELY. Then, it must be cleaned ASAP. Fresh water can work in a pinch, but it MUST be blown out thoroughly with compressed air before you hook it up again.

LOFL! When I worked for Lear Corp, the worst were the engineers with degrees in automotive engineering. I once had to take ALL of the tools away from one of the engineers as he repeatedly hurt himself with his caliper! Curiously, the best engineers I've ever known, save one were barely high school graduates.

Contact cleaner is an organic solvent. When you're in water like this, you need an aqueous cleaner to remove the salts that are causing the problem. You're far better off using ANY water to rinse the circuit board, then use clean water, then alcohol, then contact cleaner-if you think you need it.

I clean circuit boards all the time under the kitchen sink using a clean tooth brush.

 

[crystalclear]

ok, in case anyone was waiting for the results:

what i did:

- new maf
- cleaned plugs for rear o2's
- pulled out the tcu - cleaned and dried (with electric circuit cleaner)
- did 1 drain/fill of atf (4.5-5qts)

results:

- all codes gone
- transmission function returned to normal

perhaps by miracle or just plain old not deep enough - when i drained the atf - it was basically still red/reddish (i had just drained/filled 4k miles ago) --- no signs of water, strawberry milkshake, chunks of melted clutch stuff, etc....

i assume there was no water as i drained into a clear container and it was red red all the way....

so, i guess i may have dodged a huge bullet, and will be doing another 1-2 drain/fills over the next 200-300 miles...

honestly - the truck is running smoother than before this whole ordeal...

thanks for all the help!

 

[R_Lefebvre]

Had you recently ran the truck before draining? Water can settle out and not give the milkshake appearance if you've waited too long.

I think you might be fine. Just saying.

Contact cleaner is an organic solvent. When you're in water like this, you need an aqueous cleaner to remove the salts that are causing the problem. You're far better off using ANY water to rinse the circuit board, then use clean water,

So you're suggesting to use water full of salts to clean off the water full of salts? I guess if one carries around deonized water in their truck, great. Otherwise, no.

 

[crystalclear]

Had you recently ran the truck before draining? Water can settle out and not give the milkshake appearance if you've waited too long.

I think you might be fine. Just saying.

well, im definitely still worried about the trans..but nothing i can do at this point besides flush a couple more times and hope for the best....

the truck had not been run for a day

so, for my next flush, which ill probably move up to @ 50-80 miles, should i run the truck for a few miles, then do the drain asap?

and, can/should i do the next flush earlier? or does 50-100 miles sound fine?

paranoia sinking back in.....

ps - the maf was changed due to a thrown code

 

[ptschram]

So you're suggesting to use water full of salts to clean off the water full of salts? I guess if one carries around deonized water in their truck, great. Otherwise, no.

Now you're being silly. Drinking water would be far better than muddy water, followed by a rinse of alcohol.

Even my softened well water is sufficient to wash away the corrosion on the boards I clean.

 

[R_Lefebvre]

You're making an argument for no reason other than to argue with me.

Now you're being silly. Drinking water would be far better than muddy water,

Try to pass 12V through water. You can. Therefore, even clean water can short out a board. Why would you use use water to clean a board?

If somebody has drowned their truck in muddy water, and all they have is drinking water, you going to tell them rinse it off in the drinking water, reinstall it and go? No, it'll still short out.

Sure, alcohol would be a good choice. Brake cleaner works too.

Again, you like to criticize engineers for being too theoretical, and here you are arguing with a guy who actually cleaned his TCU with brake cleaner, and it still works to this day.

Far better to use an aqueous cleaner? How can anything be "far better" than something that just plain worked? The thing is still working. It's currently telling my ECU that there's something wrong with the Range Selector Switch, and the shift solenoids. :lol:

I didn't say brake cleaner was better than water or alcohol. I said it was better than WD40. And it is.

You just jumped at the first chance to argue with me for some reason.