How hot does auto transmission oil get? (Page 1/2)
Cliff Pennock AUG 12, 08:16 AM
Trying to find a hose I can use to repair the transmission lines near the radiator. Most hoses I find can withstand the oil but are rated to about 100C (212F). Would that be enough?
Dennis LaGrua AUG 12, 08:37 AM
Transmission oil in a vehicle can be as low as 160*F but in rare cases can go as high as 225*F. My Fiero typically sees trans oil temps in the 165* area. While the Fiero has a trans cooler in the radiator it is a small one but the long lines leading to the front IMO may help somewhat. You can use an infrared pyrometer to check the temps.

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Spoon AUG 12, 08:49 AM
Cliff, consider an external transmission cooler. Just google "External transmission cooler". I've used them as far back as the Original GTO days when converting from manual trans to automatic. Plus its external of the radiator so no chance of coolant being preheated to some degree.

https://transmissioncoolerg...ransmission-coolers/

https ://www.amazon.com/Hayd...84001431364292&psc=1

https://www.amazon.com/EVIL...Z2V0TmFtZT1zcF9tdGY& psc=1

Spoon


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[This message has been edited by Spoon (edited 08-12-2023).]

theogre AUG 12, 10:06 AM
Read the Cave.
The Heat Exchanger is in the Hot Side of the Rad to Maintain AT Heat.
Is "wrong" to say "coolant lines" etc because is Not a Cooler Many Times but nearly everyone says Cooler...
Because is only a Cooler when Oil is Hotter the Engine Coolant. It Heats the Oil when cooler than the Engine Coolant temp. Engine Cooling Temp is often above 100°C/212°F in hot side tank.

Most Aftermarket Coolers are installed wrong and cooler the Oil to much and Oil doesn't get hot enough to do it's job. More so since w/ most AT have TC Locking because Unlocked TC make most of the heat. Lock TC removes 80-90% of heat generated and drive in cool to cold weather the Trans Oil get Too Cold.

Other hoses may say can handle oil still Fails carrying AT Oil and not just the Heat.
Oils have different Base Formulas to start then add whatever Additives and "hate or love" rubber/plastics they touch.

J1532 TOC (Trans Oil Cooler) hose is made to have Dextron Mercon and other AT Oils.
That often Fails carrying other oil and petrol more so petrol w/ ethanol and other alcohol.
olejoedad AUG 12, 11:34 AM
The Ogre is correct on all accounts in the above posting.
82-T/A [At Work] AUG 12, 01:29 PM
In the two Fiero fires I've had... both were as a result of failing transmission coolant lines. First was an 84 Fiero that had not been "highway driven" for almost 5 years (just short distances). It split and shot a steady jet of transmission fluid directly on the catalytic converter... I created a smoke screen on the highway, and only noticed because no one was passing me for several minutes... hahah....

But keep in mind that there's apparently a point to having the transmission line "loop" on one end (can't remember if it is out to radiator cooler, or back in from radiator cooler); however... I knew at one point (hopefully someone mentioned above), but you don't want to lose it. It had something to do with air in the line, or preventing it, or... I have no idea, I just remember someone telling me it was really important to ensure you maintain that. I think there's even a little holder that's supposed to maintain that loop.

(someone correct me on this please, would like to know...)
Cliff Pennock AUG 12, 03:45 PM

quote
Originally posted by theogre:

J1532 TOC (Trans Oil Cooler) hose is made to have Dextron Mercon and other AT Oils.



Yes, but like I said in the other post, I can't get that hose here. So I need to find a hose by specs.
82-T/A [At Work] AUG 13, 12:10 AM

quote
Originally posted by Cliff Pennock:

Yes, but like I said in the other post, I can't get that hose here. So I need to find a hose by specs.




Wouldn't any automatic transmission line that you buy in the Netherlands also work? I wouldn't imagine they'd be too different. Just get something that's meant for an older pickup truck I'd think... and bring some of the old rubber transmission line with you.
Cliff Pennock AUG 13, 07:07 AM

quote
Originally posted by 82-T/A [At Work]:

Wouldn't any automatic transmission line that you buy in the Netherlands also work? I wouldn't imagine they'd be too different. Just get something that's meant for an older pickup truck I'd think... and bring some of the old rubber transmission line with you.



Oddly enough, hoses are never marked as "suitable for transmission oil". I in fact went to a parts store and when I asked for a rubber hose suitable for transmission oil, they said they didn't have any and were not aware if it even existed. I checked quite a few Dutch car forums and apparently, people use hydraulics hoses to replace transmission lines. So that's what I ended up ordering. It can withstand pressures up to 5000psi, temps up to 212*F, and should be suitable for transmission oil.
82-T/A [At Work] AUG 13, 12:45 PM

quote
Originally posted by Cliff Pennock:

Oddly enough, hoses are never marked as "suitable for transmission oil". I in fact went to a parts store and when I asked for a rubber hose suitable for transmission oil, they said they didn't have any and were not aware if it even existed. I checked quite a few Dutch car forums and apparently, people use hydraulics hoses to replace transmission lines. So that's what I ended up ordering. It can withstand pressures up to 5000psi, temps up to 212*F, and should be suitable for transmission oil.




That's pretty smart... I mean, I guess that's literally what it actually is!