gearbox malfunction - overheating issues

[RudyH]

I was thinking about one of my gripes that has been coming back after doing a mech unit repair a few years ago. With the warmer weather I was noticing that if stuck in bumper to bumper traffic, my transmission starts shifting terribly. After parking it especially over night, it seems to go back to normal, but whenever I have a bad shifting day, the car seems to not quite drive like it did before. Just so happened an ad from APR popped up in the forum and this exert got me thinking :

Temperature management is an important part of the DL501 transmission. While some may simply remove temperature protection routines all together, or mistakenly raise temperature protection torque limiters sky high and claim increased cooling performance due to zero transmission intervention, APR’s TCU upgrade only allows the maximum safe temperature levels before intervention. Under high stress scenarios, such as launch control, the transmission’s cooling pump runs at maximum speed until the desired transmission temperature is achieved.

Unlike the factory intervention routine, which allows for nearly no torque to be transmitted through the transmission at all after limits are crossed, APR’s over temp intervention allows for a limited amount of torque, enough so the vehicle can be safely driven off the track or pulled to the side of the road during intervention. In keeping the vehicle moving, airflow continues across the radiators, which in turn keeps coolant temps low and aids in removing heat from the factory DL501 oil coolers to restore full operation.

------------------

Do you think a lot of the gear box malfunctions are a result of overheating? Well based on the information posted below, I think that is a resounding yes. I have the v1 of the DL501.
Does anyone have any information on how the cooling system works on the DL501?

http://www.audizine.com/forum/showth...tronic-(DL501)

I'm curious if there is some type of test I can do to make sure my cooling system is functioning ok, or as most enthusiasts are rightfully thinking - modify it for cooler temperatures. To date we seem to just say 'replace the mech unit' without giving much thought to root cause. I feel if that is found, the S4 could live a long life with the DCT transmission.

[bhvrdr]

? I don't know of any DSG gearboxes that have routinely failed. There were some early model mechatronic unit failures that didn't have anything to do with overheating but rather corroded wires and speed sensors...

https://www.ecstuning.com/b-genuine-...it/0b5398009e/

but I don't know anybody who has even fried a DSG gearbox yet despite people running 500 horsepower now. You should get a gearbox malfunction and limo if u overheat it. You can log temp in vcds

[whiped]

The only gearbox malfunction I have gotten happened when the DSG was not that hot.

I have had it get super clunky at the track though when pushing it hard. This caused it to slip and short shift.

I generally try not to beat it up with 5+ back to back runs anymore.

I know of two people who have added inline oil coolers to it with some success.

[Johnnycash]

I think there is definitely some anecdotal evidence of people who have issues with dct being associated to city driving and or driving in congestion on the regular and at a high frequency vs people who routinely log many miles on open roads or the interstate and having the tranny behave better and not having issues.

For example:

1. guy who lives and works in NYC and drives his car a total of about 8 miles per day just sitting in shit traffic especially in the middle of the summer or an area down south that is hot year round doing city commutes, not only is this style of driving bad for the motor but i would deduce bad for the transmission too.

2. Me who does about 20-25k annually with 60-70% being highway miles at cruising speeds 50-70mph, I would imagine my cars internals are running much cooler than some guy sitting in rush hour in arizona in july doing slow mph day in, day out...

my car is late build 2011 with 86k on the clock, tranny mount insert and both dsg services performed on schedule, dsg had a learning curve for me, but now that I figured out the cars quirks I understand how it behaves vs a typical slushbox.

[RudyH]

Ya @Johnnycash that's what I mean

Like when I drive highway or just little trips around town on a weekend or weeknight everything is fine. The second I get into what I consider a situation where many gear changes are happening (stop and go city traffic during rush hour or highway 0-60-40-0, etc) things start going wonky. Mind you I have it in dynamic mode always and when I put it down to a more comfortable level the transmission feels better.

Interestingly as well, when I perform a reset / relearn as I had to do after a PCV valve the transmission felt great again. It seems there must be something (programming???) that is making it learn badly?

Sorry I m just trying to figure out how I can better care for this. As much as I would love to get rid of the car for something new, kinda attached to the old girl (which is unusual usually replace my cars after 3-4 yrs).

[EchelonS4]

Interesting topic. I have a 10' with 83k on the clock and have had that 2 to 1 hard shift and general clunkiness when driving in those same conditions. The stop and go driving, only after the car and trans have had time to heat up. Highway driving or normal driving (85% of my driving) I have no problems with it. I have a Mech repair kit sitting here ready to throw in and see if that helps but in the back of my mind I have always wondered if the issue has something to do with overheating issues. I love the car and do not want to get rid of it but when that issue rears its head it makes me incredibly frustrated. I've never had a warning light or anything else as well.

[RudyH]

Ya, that's my issue, is it something physically that is going wrong to fix? Like add more cooling? Or is it something as simple as doing the TCU upgrade and I am golden, plus there is so much win involved with the upgrade.
I did the mech unit repair kit already after getting the warning, but right now it's not that the mech unit is failing, it seems like a software issue because after resetting things everything feels great again, and possibly things are slowly degrading as 'bad decisions' in the software are being made.

I am also getting close to due on a transmission flush so I feel like that would clean up the last of my issues, much like when I get an oil change the engine feels nimbler again.

[davesxx01]

Surprised that no one has mentioned taking off the front bumper and cleaning out the garbage that could be plugging up the trans cooler! When I had mine apart to install a new pulley I was amazed at how much garbage was in the cooler. I used an air hose to back push everything away from the ducting and cleaned it all out !!

[whiped]

That's for the SC, not the transmission...

The ATF radiator is built into the main one front/center.

Unless I am insane, which is possible.

[cspcrx]

If there is an external cooler could the size be increased. I notice mine does not like sitting in traffic and I do notice the shifts change, much more harsh.

BMW has an upgrade kit for their 335s. Surprised no one has made one for the S4s.

[theweebabyseamus]

If there is an external cooler could the size be increased. I notice mine does not like sitting in traffic and I do notice the shifts change, much more harsh.

BMW has an upgrade kit for their 335s. Surprised no one has made one for the S4s.

The 135/335 needs it a lot more it's seems like. The s4 seems to have these overheating issues less frequently whereas a stock 135/335 can trigger the errors fairly easy on a stock car at the track.

[davesxx01]

That's for the SC, not the transmission...

The ATF radiator is built into the main one front/center.

Unless I am insane, which is possible.

Thought the SC one was the very front center, I'm talking about the one that is in the lower left (drivers side) corner in front of the tire. It has a duct around it and I removed it all and cleaned all the leaves and junk out of the fins then used the air hose to blast it from the back to finish clearing out the junk.

Edit: Oops! I thought this was a trans cooler! #2 with the #5 ducting!

[RudyH]

If there is an external cooler could the size be increased. I notice mine does not like sitting in traffic and I do notice the shifts change, much more harsh.

BMW has an upgrade kit for their 335s. Surprised no one has made one for the S4s.

From APR's blurb I posted above : "In keeping the vehicle moving, airflow continues across the radiators, which in turn keeps coolant temps low and aids in removing heat from the factory DL501 oil coolers to restore full operation."

So yes I would too like to know where those radiators are. Hopefully the CPS aren't blocking the transmission ones cause me what I believe are heating issues?

[theweebabyseamus]

Thought the SC one was the very front center, I'm talking about the one that is in the lower left (drivers side) corner in front of the tire. It has a duct around it and I removed it all and cleaned all the leaves and junk out of the fins then used the air hose to blast it from the back to finish clearing out the junk.

Edit: Oops! I thought this was a trans cooler! #2 with the #5 ducting!

#2 is an auxiliary heat exchanger for the s/c, and only appears on the B8's.

[Chunchoy14]

Its in the radiator. You have to account for adequate line pressure(ext fluid pump?), cold start temperature warmup cause the dsg doesnt like running to cold(thermostat?), and fluid capacity. Has anyone tried datalogging the fluid temps in and out of traffic?
Looks like you can attach fittings to the end of the hard line before the hose. Definitely doable.

[bhvrdr]

It might be a good idea to confirm if we are actually having any overheating issues though before we try and increase any Cooling. These Transmissions have a temperature range they need to run in and adding a cooler to something that is running in the right range would be a very bad idea

[grovlet]

It might be a good idea to confirm if we are actually having any overheating issues though before we try and increase any Cooling. These Transmissions have a temperature range they need to run in and adding a cooler to something that is running in the right range would be a very bad idea

That's a good point.

Also I wonder about swapping fluids to an aftermarket one vs OEM? I just had my Mechatronics replaced - but prior to that had thought about switching to Amsoil DCT Fluid (and still might when I next change fluid in 25K miles (erring on side of caution))

[Chunchoy14]

Datalog the temps. I dont think anyone has yet. Ill do it next time im in traffic

Sent from my LG-H810 using Tapatalk

[Jroyalty7]

http://www.usrallyteam.com/index.php...oducts_id=1908
Not sure if this applies to us but gives a good concept

Sent from my SM-G955U using Tapatalk

[Chunchoy14]

Thats a nice kit. Wish it would fit. Actually it might be really easy for us as we have the line that we can easily put a fitting on to run to a new cooler.
Where the line bolts to(black thing with ext filter)

Sent from my LG-H810 using Tapatalk

[mgaman]

There is an existing TSB for this exact issue where the 7-speed DSG has issues due to heat generated from slow speed stop and go traffic.

[bhvrdr]

I'm curious how many folks are getting the overheating malfunction message. Unless you have a broken temp sensor we should know if the temps go too high out of spec bc a warning message will be displayed

[TuanQT]

Hey bhvrdr i tried to send you a PM but it keep not sending could you send me one and we can talk in private ?

Sorry for hjacking OP

[RudyH]

Datalog the temps. I dont think anyone has yet. Ill do it next time im in traffic

Sent from my LG-H810 using Tapatalk

That would be awesome if you don't mind? I wouldn't say it's rare for me to be stuck in traffic, but it's been a cold summer (where the rest of the world is complaining about a hot summer) - and I don't have plans to go to Toronto to be stuck in traffic. Just a few weeks ago I was. Also I haven't exactly tried data logging yet so not sure the data I would be collecting would be worthwhile. Just observation

- - - Updated - - -

There is an existing TSB for this exact issue where the 7-speed DSG has issues due to heat generated from slow speed stop and go traffic.

Do you know what the TSB # is? This is the only one that is kind of close

2011 - 2012 TSB-37-13-90
103100 POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM, PCM)
AUDI: PSS 37 TRANSMISSION WARNING MESSAGE IN CLUSTER. GEARBOX IN LIMP MODE, FAULT P17E100 STORED IN TCM. THE FAULT IS SPORADIC AND USUALLY APPEARS AFTER A COLD START. FAULT IS CAUSED BY TRANSMISSION SOFTWARE THAT IS TOO SENSITIVE. *JS

http://www.allworldauto.com/tsbs/aud...65-1626-1.html

[EchelonS4]

How do you go about resetting the software? Is that something only a Dealer can do? I bought my 10' used 2 1/2 years ago with 58k on the clock and now have 84k and can say I have had this "issue" since shortly after I bought the car. Im curious if a fluid change, software reset, etc. might help to clean some things up.

[RudyH]

How do you go about resetting the software? Is that something only a Dealer can do? I bought my 10' used 2 1/2 years ago with 58k on the clock and now have 84k and can say I have had this "issue" since shortly after I bought the car. Im curious if a fluid change, software reset, etc. might help to clean some things up.

My mechanic did it for me when he replaced my supercharger water pump, and again the PCV valve - he is not a dealer. It was a process which took like 15 minutes and he referred to it as 'relearning'. I'm not sure if it's as simple as disconnecting the battery for xx time as Google search suggests, I think there is something you trigger in the ECU

[mgaman]

@rudyH I'll try to find it for you. I looked a bit yesterday and couldn't find it, but I know it exists (or existed?) because I looked them all up before I bought my 2010 :)

It was something about how repeat stop and go and slow speed traffic could cause overheating in the transmission due to heat build up in the clutch packs.

[EchelonS4]

I wouldnt mind seeing that either! The way you described it sounds just like my car and its a 2010 as well.

@rudyH I'll try to find it for you. I looked a bit yesterday and couldn't find it, but I know it exists (or existed?) because I looked them all up before I bought my 2010 :)

It was something about how repeat stop and go and slow speed traffic could cause overheating in the transmission due to heat build up in the clutch packs.

[Charle01]

Audi a3 1.4 tfsi 7 speed dsg says transmission overheating.

[wrxkyle]

is there a separate sensor for clutch temperature? i can't find one but always been curious if the trans meters the clutch fluid separate from the dsg fluid or if they are all one circuit. when these trans have an overheat code but the trans fluid isn't past 80c is that because the clutches are slipping and overheating or just because the trans is incorrectly interpreting the fluid temp?

[fastboatster]

“Clutch” and dsg fluids are the same, the same fluid is used to apply the pressure to the clutches, cool them and transmit the pressure on hydraulic actuators. There’s a sensor for the clutch temp, it measures the temp of the fluid flowing out of the clutch pack. You can’t see it in OBD11 but VCDS will show it.

[wrxkyle]

“Clutch” and dsg fluids are the same, the same fluid is used to apply the pressure to the clutches, cool them and transmit the pressure on hydraulic actuators. There’s a sensor for the clutch temp, it measures the temp of the fluid flowing out of the clutch pack. You can’t see it in OBD11 but VCDS will show it.

good to know thanks, wasn't sure if it was actually measuring the clutch temp or just the fluid temp as a whole

[wrxkyle]

“Clutch” and dsg fluids are the same, the same fluid is used to apply the pressure to the clutches, cool them and transmit the pressure on hydraulic actuators. There’s a sensor for the clutch temp, it measures the temp of the fluid flowing out of the clutch pack. You can’t see it in OBD11 but VCDS will show it.

followup question, when you get a clutch temp overheat warning and the fluid temp isn't super hot is that because the clutch fluid temp is actually overheated coming out (ie mechatronics failure causing slipping clutches which then overheat vs mech failure causing false positive readings of overtemp condition.

[fastboatster]

followup question, when you get a clutch temp overheat warning and the fluid temp isn't super hot is that because the clutch fluid temp is actually overheated coming out (ie mechatronics failure causing slipping clutches which then overheat vs mech failure causing false positive readings of overtemp condition.

Tough question- my guess is that it can be both. Remember, some people had issues with mechatronic pcbs. Bad continuity there can cause bad temperature reading, but if pcbs are okay then it’s definitely possible that the clutch temp is way too high, they definitely can be worn or slipping under excessive torque or not getting enough cooling oil flow.