4hp22 operating temp

[shack]

Recently decided to pull down an auto box that we got in a wrecker we bought years ago that had a "failed transmission" the torque converter was badly damaged, probably from a flex plate failure.

But I think it might have got a bit hot as well...

No need for the Ashcroft sump sticker for temps on this one!


https://uploads.tapatalk-cdn.com/20230509/8c825325e44bf849bcaa91740aa0506a.jpg

[Slunnie]

This is why they are "Sealed for Life". You don't need to see this stuff. :lol2:

[shayne86]

Bloody hell!

[Pedro_The_Swift]

Just to add some "more" ZF goodness.. My 8speed runs at around 5deg warmer than the coolant, so nearly always above 100degC, towing, not towing, Sport or Drive doesnt seem to make any difference...

Great Pic!![bigrolf]

[gavinwibrow]

Just to add some "more" ZF goodness.. My 8speed runs at around 5deg warmer than the coolant, so nearly always above 100degC, towing, not towing, Sport or Drive doesnt seem to make any difference...

Great Pic!!


from Ashcrofts
Automatic transmission oil can provide up to 100,000 miles of service before oxidation requires replacement, at an operating temperature of 79°C. Above this temperature, the oil oxidation rate doubles with each 11°C increase in oil temperature. See chart below.







DEGREES F / C


[B]MILES / Km


DEGREES F / C


MILES / Km




175 / 79


100,000 / 162,500


295 / 146


1,500 / 2,438




195 / 90


50,000 / 81,250


315 / 157


750 / 1,219




215 / 102


25,000 / 40,625


335 / 168


325 / 536




235 / 113


12,500 / 20,313


355 / 179


160 / 260




255 / 124


6,250 / 10,156


375 / 191


80 / 130




275 / 135


3,125 / 5,078


395 / 202


40 / 65



Note: Transmission oil and filter should always be changed more frequently when driving with heavy loads (RVs), typically at least every 25,000 mile intervals, since converter outlet temperatures then normally far exceed the ideal 79°C.

[rick130]

from Ashcrofts
Automatic transmission oil can provide up to 100,000 miles of service before oxidation requires replacement, at an operating temperature of 79°C. Above this temperature, the oil oxidation rate doubles with each 11°C increase in oil temperature. See chart below.







DEGREES F / C




MILES / Km




DEGREES F / C




MILES / Km






175 / 79




100,000 / 162,500




295 / 146




1,500 / 2,438






195 / 90




50,000 / 81,250




315 / 157




750 / 1,219






215 / 102




25,000 / 40,625




335 / 168




325 / 536






235 / 113




12,500 / 20,313




355 / 179




160 / 260






255 / 124




6,250 / 10,156




375 / 191




80 / 130






275 / 135




3,125 / 5,078




395 / 202




40 / 65





Note: Transmission oil and filter should always be changed more frequently when driving with heavy loads (RVs), typically at least every 25,000 mile intervals, since converter outlet temperatures then normally far exceed the ideal 79°C.


The 8 speed runs a full syn oil from the factory so 100* is well within it's operating range, whereas the old Dexron II/III oils were straight mineral oils so you needed to keep the operating temps under control to minimise oxidation.
Of course it's not just the oil that cops a flogging with higher temps.
The viscosity reduces so the fluid film is thinner, and elastomers, eg. seals and O rings start to harden/prematurely age with higher temps.

That photo above in the first post though is a cacker!

[shack]

Just to add some "more" ZF goodness.. My 8speed runs at around 5deg warmer than the coolant, so nearly always above 100degC, towing, not towing, Sport or Drive doesnt seem to make any difference...

Great Pic!![bigrolf]That sounds really warm to me, as Rick has pointed out, it's not just the oil that is an issue.

Are you getting any flaring or shuddering with the converter locked?

I've logged our 6hp and we work it hard, it'll easily hit those temps towing... And then some, but when just cruising on the highway at 110 km it's probably in the 80s.

[ozie]

HI all on the subject of temperatures anybody know the thread of the bolt/plug that are next to the transmission lines - I hear this is a good spot to fit a temp sensor, any research has come up empty on this ??

[John_D4]

Really sorry guys but I don’t know that much about auto internals. I used to do the trans filter and oil in the D2 but I haven’t in my 3.0.

What am I looking at in the pic?

[shack]

Really sorry guys but I don’t know that much about auto internals. I used to do the trans filter and oil in the D2 but I haven’t in my 3.0.

What am I looking at in the pic?I'd you are referring to the pic I posted, it is of a 4hp22 with the sump off, the protective "sheath" on the wiring has got so hot it's melted.

[John_D4]

I'd you are referring to the pic I posted, it is of a 4hp22 with the sump off, the protective "sheath" on the wiring has got so hot it's melted.

Right…that’s a slightly bit hotter than recommended operating temp!

Thanks for explaining

[admiralranga]

HI all on the subject of temperatures anybody know the thread of the bolt/plug that are next to the transmission lines - I hear this is a good spot to fit a temp sensor, any research has come up empty on this ??

m14x1.5, hunt hard enough there's a vdo sensor to suit or do the sensible thing and fit an adaptor to 1/8 npt. There's more info in here New Allisport transmission cooler - Page 2 (aulro.com) (https://www.aulro.com/afvb/discovery-2-a/251007-new-allisport-transmission-cooler-2.html) and here What happened to your Discovery 2 today? - Page 252 (aulro.com) (https://www.aulro.com/afvb/discovery-2-a/232420-what-happened-your-discovery-2-today-252.html#post2731424)