1999 750il 5hp30 operating temperature

[ArlingtonBeech]

I was curious what the normal operating temperature for the 5HP30 was? I have had difficulty finding it, after a lot of searching.

I took the 750 out for a drive yesterday where the outside temp was 40 F and had inpa running for about 30 minutes of driving time. It showed the temperature to be steady around 233 F

is that normal?

The transmission has the P0740 error, im saving some money for a new torque converter, should have it soon.

I have done several fluid changes as well.

[TheAngryBear]

That is about 112°C which is a little on the high side. I am in a M73N and run normally about 104 with excursions up to 108 sitting in traffic.


2001 750iL DD74441
Stock

RIP: 2003 540iA Sport GS56111
H&R front springs, Ultimate Cup Holder, Euro Dash & Armrest, Grom, BavSound Stage1

[ArlingtonBeech]

I was thinking it should just above engine coolant temp, because of the heat exchanger.

Could it be a problem with the transmission? Or maybe a problem with the heat exchanger/ regulator on the exchanger?

Or, Perhaps because it is not going into lockup?

[TheAngryBear]

Yeah, technically all ZF says is that to properly check it you need to get about 75°C then cool down to 35°C for fill etc. The only max I see is that it should be below 200°. But it doesn’t say F or C...

http://etereman.com/blog/luxury-tran...c-transmission

https://aftermarket.zf.com/remotemed...pdfc-5hp30.pdf

https://www.zf.com/global/media/medi...t_50145_EN.pdf



2001 750iL DD74441
Stock

RIP: 2003 540iA Sport GS56111
H&R front springs, Ultimate Cup Holder, Euro Dash & Armrest, Grom, BavSound Stage1

[ArlingtonBeech]

So i just did some transmission work, such as installing a new valve body. I have had INPA running while driving and the transmission temp has climbed to 253F, i think that is high.

Would any body else be willing to drive with INPA on or some other way to get the temp range for their 5HP30 with a possible ambient outside temp of around 90F, after driving and find out where the temp stabilizes?

I am currently dialing in making sure it has the right amount of fluid, its taking a bit of trial and error.

[ArlingtonBeech]

So for good measure I checked again and it looked to stabilize at 246.2 F

I emailed ZF and told them the temp the 5HP30 was running and asked them what the normal temp should be. They replied saying that 246.2 is borderline dangerous. They said the normal temp should be 175 to 215.

I changed the trans thermostat and the heat exchanger. In the morning i'm topping off coolant and transmission fluid. I'll double check the temps again tomorrow and see.

[chrisn7]

How are you topping off the transmission? This needs to be done with the car level, engine running, and transmission temp between 30 and 50C, but as near to 30 as possible.

[redlinebanging]

I know they change the cooling setup for the 99+ 750 to be connected to the whole coolant system..
I have a 98 750 and its 150F -185F. even today it was 100f in Tampa and I was doing 175F trans temp after driving to work.

[ArlingtonBeech]

How are you topping off the transmission? This needs to be done with the car level, engine running, and transmission temp between 30 and 50C, but as near to 30 as possible.

I had did everything just like that, except, start engine. Today and yesterday I started engine ran through all gears with car level. After starting it I added around a liter yesterday, today I didn't add any it was good.

i drove it today and the temp climbed to 246 again. I checked the transmission pan and it showed around 200. however i parked on the incline of my driveway and checked the rear of the transmission pan and it displayed 240ish

So i believe the transmission is actually running at that temp, before I figured it was a fluke.

I'm lost about now and have had enough, i'll just drive it and enjoy it till the transmission falls out, or catches fire.

[TheAngryBear]

Are you getting any codes (actual or pending/shadow)?
See how hot the transmission heat exchanger is. You might have blockage or constriction there. It could also be on the radiator coolant side. You did change it, so hopefully functional...
Check the pipes and hoses for restrictions (kinks, damage, etc.) as that could cause it as well.
What filter is in the transmission? Could be failed or stopped up causing flow issues.
Also, hate to say it, but you may need to do another fluid change. Once elevated and “burnt” from being low a top-off might not do much.



2001 750iL DD74441
E65 fan & clutch, E65 headrests, Front First Aid Kit, Ultimate Cup holder

RIP: 2003 540iA Sport GS56111
H&R front springs, Ultimate Cup Holder, Euro Dash & Armrest, Grom, BavSound Stage1

[ArlingtonBeech]

When I changed the heat exchanger and regulator I lost almost all coolant from the three hoses so i'm pretty sure it's getting coolant there. There was also a loss of Transmission fluid when I changed it, but not a bunch. The temp gun says the heat exchanger is around 195 at the same time as I measured everything after a drive.

filter is everyone's recommendation of the one stamped with "filtran"

When I got back it showed a torque converter lockup clutch, which I have got in the past, I figured there would be a slight increase if not going into lockup but this seems a bit much (I should have mentioned this earlier, but it heats up the 240 F even idling during my testing which is why I didn't mention it)

[ArlingtonBeech]

My transmission is still running hot, around 250 F.

About a week ago I pulled the two cooling lines off the heat exchanger and blew air through them. when blowing air through the inlet hose to the transmission the air was blocked. After steadily blowing i heard a thunk and air flowing into the transmission and some fluid came out. So i drove the car and it still ran hot.

So today I tried again and there is still a blockage but I heard the thunk again when i blew enough air through the inlet pipe, but again before air went through there was still an obvious blockage.

Is there supposed to be some type of block or valve on inlet pipe? I could not find any indication anywhere

[MJeffC]

That is definitely too high. Should be less than 200 most of the time.
The trans cooler has a coolant thermostat which can fail(never seen one that did).
It is probably blocked passages in the cooler, thermostat or the radiator.
Has your 750 ever had radiator stop-leak in it?

[ArlingtonBeech]

I blew air through the cooler lines and through the heat exchanger, no blockage. Both the heat exchanger and thermostat are new (not saying the couldnt fail though)

But when i tried to blow air through to the transmission the outlet line flowed through into the transmission but the inlet line was blocked unless i put a lot of air through it.

I was just curious if there was a valve or something at the inlet port at the transmission before i replaced the radiator.

[MJeffC]

The black part above the transmission cooler is the thermostat aka "voltage regulator". Is that new or do you mean the coolant thermostat at the water pump? Blowing air is not a good indicator of blocked water passages. I would run water from a hose through them.

1. Does water flow out freely from the hose at the bottom of the radiator when you disconnect it?
2. Has your radiator ever had stop-leak in it?

[ArlingtonBeech]

the voltage regulator is new. I did not blow any air through the coolant lines at the heat exchanger, just the transmission fluid passages

1. When i changed the voltage regulator fluid flowed freely out of radiator and a lot of it.
2. No stop leak ever in radiator, in fact last year I had the dealer do a coolant flush.

I was leaning towards a possible blockage in transmission itself, since coolant flowed out of transmission.

[MJeffC]

Since booth cooler and thermostat are new AND the coolant flows freely from the rad to the cooler, then they are probably not the cause.
How many miles and has the trans filter been changed before?

[ArlingtonBeech]

I replaced the filter and changed fluid back in December a few thousand miles ago. I'm going to temporarily secure and route the old heat exchanger to the transmission lines and check fluid and fluid temperature with vehicle running; but NOT too coolant system. If it temperature of that heat exchanger raises with transmission temp and I can verify fluid flow in and out of transmission then i'll know the problem lies with the coolant system.

i'm thinking this is a good course of action.