My Kingdom for the ZF4HP auto sump plug thread size !!!

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Originally Posted by bee utey

The oil temp in the pipe pre cooler will be a much more relevant temp reading than you think. The oil has just left the torque converter in high dudgeon where it's just had it's ass thrashed, then returned to the sump after being cooled down a wee bit. Clamping a sensor via a split brass block to the hot pipe nearer the trans might possibly give you a similar reading.

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Originally Posted by workingonit

Hoping your 'filter kit' included the one residing inside the sump (bolted to the valve system). Nice to start everything off fresh.

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Thanks BeeUtey. You're probably dead right, but I can't find anyone who's ever found out for sure. I could live with say 2 degrees, but 5-10 is getting a bit inaccurate (esp if I'm going to the time and trouble), and I'll never know if I just bung one in the OEM spot.


My backgrounds in instrumentation, electrickery, plumbing and solar energy have taught me that there are usually large temp differentials even in a single bulky device, heatsink or pipe etc, and the $4k worth of blown head gasket makes me a bit paranoid about how the poor old auto's going. The skilled and experienced scribes on this forum make it clear that there will be fairly large differences in temps between the ZF body and the lovely red stuff circulating through its arteries also, but one can take obsession only so far I think.


After weeks trawling through Aulro and the wider net, there seems to be many and varied options and much learned head scratching for sensing the auto temp, but I don't understand why we can't just bung a temp sender in an adaptor in one of those two M20 x 1.5 pressure ports in the bottom of the ZF oil pump stator/intermediate housing (or any of the other hex head/key fixings around there) ?


I know virtually nothing about autos, other than the overall concepts, so I haven't a clue if that's going to work or damage anything, or if it's going to sense one of the hottest points. Just seems the simplest, hottest and best option (and avoids flimsier T-pieces, brazing/welding the sump etc).


So, plan D:
1. Unless someone (please) throws their hands up in horror at some ghastly mistake I'm about to make, I'll bung a 1/8" NPT temp sensor in an M20 x 1.5 adaptor in one of the plugs in the bottom of the ZF stator/intermediate housing (if'n I've got the name of the doodad right).
2. I've got a spare TM engine/transmission dual monitor with bolt on sensors, so I'll fashion close couplings for them and temporarily mount one each on the box and the OEM temp switch spot. (For info, those things conduct heat rapidly, so accuracy hinges a lot on close coupling and keeping them out of large air movements) (and for a further fascinating bit of trivia, the sensors epoxied inside them are highly complex 64 bit microprocessors, with all sorts of data registers and coded communications busses - designed so you can wire a large number of temp sensors on a single wire)
3. This will hopefully provide a good idea of the oil and box's working temps, and whether I'm just being a worry wart about finding the best spot for monitoring the ZF's temp. If anyone's still awake or interested by now, I'll post the results when I get 'em.




My sincerest apologies to everyone if I'm asking questions that have been done to death elsewhere, but despite my long and exhaustive searches, I just can't find 'em.


Thanks for your note also Mr/Ms Workingonit. Yes, I changed the box's internal gauze filter, O rings and gasket. Oil was reasonably clear, though a little darker than new, and it smelt a tad burnt (I did a cuppla changes maybe 20k ago, and the box doesn't do much heavy work). Box magnet was covered in moderate fine ferrous fluff, but like I always say, nothing wrong with a bit of fluff on ya ... ouch ... these mod's are a humourless lot aren't they ?

Plan D results, in case it helps anyone:
1/8"NPT temp sender mounted in 1/8"x1/4" brass adaptor in M20x1.5 brass plug in M20x1.5 port closest to hot oil exit to cooler.
Very easy job, very well protected behind mass of box, and heavy steel cooler pipes.
Only lose about half a cup of oil when removing these plugs.
NPTF threads leaked badly at 150psi pressures, so lotsa Loctite 272 (far too strong, but had it there, and it's hi temp) and let it dry a bit before use.

Tested:
Kerb wt plus about 100kg (using increasingly fat dog for realism)
Cool day, moderate rain
Brought up to running temps, then driven under easy to firm load up and down 20km of good condition, uphill, high speed road (Moonbi hills)
Light load: just over 70*C
Firm load: ~90*C

Seems in line with expected normal figures found elsewhere.
Closer to source of most heat.
No fiddling with welding bosses in sumps, or devising reliable tees in oil lines.
Less (theoretical) chance of inaccuracy due to heat losses/differentials over pipe or adaptor surfaces.
Need to make an M20x1.5 (outer) x 1/8"NPT (inner) adaptor, to reduce opportunities for leaks.
Cant think of any risks of using the oil pump stator/intermediate housing ports, but I don't know anything about autos and I'd love to hear if I've done something horribly wrong.

Hope this info might be useful for something.

Sounds like it is working ok. I'm not familiar with the type of sensor you are using. The only potential problem I can think of is if the sensor tip goes walk about, either into the fluid flow, or blows out of its housing and on to the ground. I had an oil pressure sensor blow out of its ceramic core once, resulting in an engine rebuild - constant expansion and contraction cause the bonded parts to separate.

I had a fatdog on my laptop today, then a puppy. But they got chased away by a Xubuntu.

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Originally Posted by workingonit

I had a fatdog on my laptop today, then a puppy. But they got chased away by a Xubuntu.

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But the real question is doth thou identify as a man or woman?!

Good to see you got it all sorted.

(curious) When was the trans serviced/fluid changed?

Sounds like you used the trans cooler pipes directly :question:

My eventual plan(if I ever get around to it), is to tee off at the temp sender unit(that's playing up!) with whatever sender unit I end up getting/using.

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Originally Posted by AK83

Good to see you got it all sorted.
(curious) When was the trans serviced/fluid changed?
Sounds like you used the trans cooler pipes directly :question:
My eventual plan is to tee off at the temp sender unit

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Originally Posted by workingonit

I'm not familiar with the type of sensor you are using. The only potential problem I can think of is if the sensor tip goes walk about, either into the fluid flow, or blows out of its housing and on to the ground. I had an oil pressure sensor blow out of its ceramic core once, resulting in an engine rebuild - constant expansion and contraction cause the bonded parts to separate.

I had a fatdog on my laptop today, then a puppy. But they got chased away by a Xubuntu.

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Bought the old girl in 2010: Detailed records and receipts show oils but no repair or adj.
Clock now about 278000km. Changed lovely ... red ... stuff about 20kkm ago, and doing it again now.
Left the pipes completely alone. Used one of 4 (?) pressure test ports on the bottom of the intermediate housing.
Removed blanking plug, inserted sender adaptor plug, nothin' up ma sleeves, good for your hands while you do the dishes.
Just don't know if the OEM site is hot enough, and not keen on the extra complexity and risks of temp losses and leaks.

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Sensor tip going walkabout ?!?!?!?!?!?! AAAAAAAAAAAAAAAAAARRRRRRGH !!!!!!
Please tell me you're just joking with me good Sir/Lady Workingonit ?!
Just when I thought I had it all sorted and it was safe to get back in the water ... shower ... oil (?) ...
Ye gods, a sensor tip lose in me box ... what a horrible thought ! O calamitous day !
I was aware of the remote possibility of it vacating the premises in external fashion, but didn't really think the internal route was a practical possibility at all. Bother !

Its a plain old VDO 50-150*C brass thingie with an M4 terminal and 2 lock nuts. I think it's essentially what VDO calls a 'thermowell', which I'd assumed was a one piece brass unit with the thermistor inserted and sealed from the external end.

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Right then, now that I've recovered a bit from that unpleasant Landroverie shock, to business:

I know what 'Xubuntu' is, and I vaguely recall some kind of 'puppy' programming language, but wot the Dreamtime is a 'fatdog' dear Workingonit ? Which brings me to Bloke/Sheila ToxicAvenger's relevant and reasonable proposal that Entity Workingonit's (and by extrapolation, all of us's) gender labelling is in fact a vital issue. Perhaps I should come out first, to start off the process of getting us all calling each other names ... I'm both Bloke and Nursing Sister, which therefore makes me half n half, and happy to be addressed as 'Sister', 'Mister' or 'Mister Sister'. There ... that clears up my labelling quite nicely I think ... after all, Docs can be either also ... I'm getting confused ...


So, ZF temp monitor plan blasted E:
1) Install EngineWatchdog TM1, with dual display and dual externally mounted bolt on sensors,
2) Mount sensor 1 on solid and wind protected location on ZF,
3) Mount sensor 2 temporarily and closely around OEM site on hot oil pipe,
4) Note any differences in box temps, and any differences between them and OEM switch site,
5) When finished noting figures and stuffing around;
- remove current VDO plug sensor (with internal tip that might one day interfere with me box, in thoroughly naughty and expensive fashion) from oil pump stator housing, and remove it's gauge,
- leave TM sensor 1 on ZF auto box
- move TM sensor 2 to new permanent position on solid part of transfer box.

Hoped for outcome:
Good idea of ZF running temps and if any significant diffs in temps between box and OEM switch site,
Permanent temp monitors on auto and transfer boxes,
Eliminates risk of tip rattling around me ZF like a ... umm ... something ... in a ... ummm ... bucket.

Many thanks for info everyone.

If any kind soul bothers to read this far, would they be kind enough to let me know of any nasty stories about temp sensors falling apart in the internal direction please ?