Transmission temp too high?..

turquise1 · #1 07-20-2012, 12:48 PM

Yes my transmission is still acting up. Same issues, after driving for a while, I will come to a stop, I step on the gas, car would not move, with higher rpms, it would jump and there is your TRANS FAIL SAFE..(Transmission is rebuilt twice, module replaced and still happening)

There is also that delay between P, R, N and D issue)

So, I do more research, and find out many people with these symptoms had valve body wiring harness issues. The temp sensor would not work properly and tranny would overheat and go crazy.

So, I decide to check the temperature in many different ways. After a half an hour warm up, the INPA soft shows gearbox temp as 100C. I read 180f from outside using my infrared thermometer (not sure how reliable). Also, my basic error reader reads Transmission fluid temp as 91F.

Now, thats confusing, I would think that 100C is too high and in that case the temp sensor is reporting wrong.

A recent visit to a transmission mech, and the guy there said my tranny fluid is burnt (changed only 2 months ago).

What do you guys think..

Ozzie..

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SlickGT1 · #2 07-20-2012, 01:15 PM

Are you using the correct fluid? As in OE fluid?

turquise1 · #3 07-20-2012, 01:25 PM

I am told by my mechanic that they used a high grade (brownish rather than red) transmission fluid.

I also had the heat exchanger and the thermostat replaced recently. Is is possible, still for the tranny to overheat (blocked hoses maybe?)

Ozzie..

TwinTurboGTR · #4 07-20-2012, 01:34 PM

Nah, that the wrong fluid. I think OE fluid is bright green from what I can remember. Or amber. Definitely not brown. Fluid should come from either straight from ZF or from BMW. I think you may have the wrong fluid in that sucker. Whether it is high grade or crap, it won't work in the gear box, which may be a slush box by now.

turquise1 · #5 07-20-2012, 01:36 PM

What about the temperatures?

That actually was my original question..

Ozzie

(As far as I know, whats being used is Dexron VI on these and thats red)

TwinTurboGTR · #6 07-20-2012, 01:40 PM

It's hard to say. there are too many variable. The temp may be accurate and does sound high, but may be caused from the wrong fluid not keeping the temp right. The outside temp read doesn't really mean much. I am sure the infrared thermo was accurate, but being it measure the outside of the case, too many variable there too. But not too sure why there is such a discrepancy between going through OBD and INPA when it is using the same computer.

But from the problems you described, especially that delay in gears, that sounds like a fluid problem and not heat related.

SlickGT1 · #7 07-20-2012, 03:02 PM

ZF fluid is Amber. And yes, it can cause your temp to fluctuate. And it is also important for the ZF box to be filled correctly. You might also have the wrong level in the trans, that can cook the oil, too low for instance.

Lots of variables here. two rebuilds and the thing is still messed up. I mean all your symptoms combined, sounds like your fluid is gone, your clutches are probably gone. Are you sure those that did the rebuild did it right, twice?

TwinTurboGTR · #8 07-20-2012, 04:00 PM

Yeah I agree. If the fluid is smelling burnt, then something is wrong. Especially if they did it twice??? Dextron is NOT the fluid that goes into these boxes. If thats what they told you is factory OE and it should work is not someone you want working on your E53. Hell I wouldn't even risk putting in Redline D4 in my box. ONLY ZF or BMW OE fluid. Period. Unless the shop doesn't mind continuing putting a new box in every 3 months, then sure, run the hell out of it.

Also, Like Slick said, wrong fluid for the right tranny, the burnt smell is either the fluid overheated, hitting the breakdown point and going bad, or there was some slippage in the clutches and the clutch material is overheating and burning the fluid.

I am just curious, if the tranny was replaced once, why was it done again?

turquise1 · #9 07-20-2012, 06:07 PM

Hey guys,

Firstly, these guys have been working with BMWs for a while, so I kinda hard to believe that they would use a wrong fluid in so many of them and get away with it.

Also, there is no burning smell, but another transmission place that I went to told me that it was burnt after a brief check up.

The transmission was opened up again after the rebuild because the transmission guy wanted to make sure that everything was ok. He said he did all the tests including pressure tests and no problems with clutches. This was done two months ago so, I cannot believe the clutches are gone already.

The car drives fine until it heats up and this problem happens when I am at a stop and try to move again. Once the TRANS FAIL SAFE happens, I can turn the engine off/on and everything is ok again for a while.

The only thing that the tranmission guy did NOT do well was to replace my valve body with a new one but a rebuilt one, so I still question that..

Transmission module come up with stall speed and gear check errors everytime, but thats it..

I can drive the car in manual mode without problems btw..

Thanks for the great input..

Ozzie..

TwinTurboGTR · #10 07-20-2012, 06:57 PM

Quote:

Originally Posted by turquise1

Hey guys,

Firstly, these guys have been working with BMWs for a while, so I kinda hard to believe that they would use a wrong fluid in so many of them and get away with it.

That means nothing. Some BMW dealerships use genaric fluid. The one by my house for example uses Redline D4 and not OE. Why? I don't know. They have 55 gal drums full of D4 and thats what they use. So being it is an indy, the likely hood they did not use ZF fluid or BMW OE is there. Am I questioning their ability, absolutely not, just putting it out there.

Also, there is no burning smell, but another transmission place that I went to told me that it was burnt after a brief check up.

The transmission was opened up again after the rebuild because the transmission guy wanted to make sure that everything was ok. He said he did all the tests including pressure tests and no problems with clutches. This was done two months ago so, I cannot believe the clutches are gone already.

The car drives fine until it heats up and this problem happens when I am at a stop and try to move again. Once the TRANS FAIL SAFE happens, I can turn the engine off/on and everything is ok again for a while.

The only thing that the tranmission guy did NOT do well was to replace my valve body with a new one but a rebuilt one, so I still question that..

Transmission module come up with stall speed and gear check errors everytime, but thats it..

I can drive the car in manual mode without problems btw..

Thanks for the great input..

Ozzie..

After reading, I mean listen. I am not knocking the ability of your tranny guy or how good he is. I am sure he is very good at what he does but if he was so good, then why go to another tranny shop? Unless it was for a second opinion or you were stranded and that was the closest shop to you when you were on the road.

As for opening it up again just to see if everything is ok is really unusual. I mean if I owned a shop, I wouldn't dedicate hours of labor just to see if everything was ok. If there was a problem, then I would look into it, but just to have a customer come back for me to open up their tranny to see if things were ok seems a bit... wierd.

The X should drive fine at start up, because the fluid is thick and cold. Once the fluid warms up, it becomes thinner. Thats why Slick and I are suggesting the fluid may be wrong. Depending on the viscosity of the fluid, if it is too thin at operating temps, the clutches are going to slip, cause heat burn themselves out.

If he didn't do the valve body well, after he cracked it open a second time, why didn't you ask for him to replace it with a new one or another rebuilt one?

Also, after the tranny was done, did he reset the adaptation values?

That was one question I forgot to ask.

Again, do not take anything I saw above as me attacking your Mechanic. Again, I am sure he is very confidant and it is good that you trust him so well to back him up. I would just ask some more questions. Open ended questions. Such as with the fluid, don't ask, "Did you use BMW or ZF fluid? Ask, "Which fluid did you use, BMW OE/ZF or something else? If the answer is fuzzy or not BMW OE or ZF, then your problem starts there. Lets say you replace the fluid with ZF or BMW OE and it still doesn't fix the problem (Atleast the RIGHT fluid is in there so you don't have to go back right as the warranty on the tranny expires and find out a different fluid was used.)

I hope that makes some sort of sense in the mess I wrote.

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