I OWN a 2005 Audi A4 2.0T AT, which I bought in April this year. On June 10, as I was going to work, the revs suddenly picked up without any increase in speed.
I reached my workplace but that was the end of the line for my automatic transmission. The car was towed from Witbank and taken to to Middelburg Audi.
It was inspected and they found that the transmission oil cooler in the bottom radiator tank was rusted and this had caused the Automatic Transmission Fluid (ATF) to leak out.
The price for fixing this was R10500. I contacted the warranty brokers, who were at first reluctant to assist me.
After I had harsh words with the warranty people (SA Warranties),they agreed to pay R4500.
The remaining R6000 I had to pay out of my own pocket - six weeks after I had bought the car. Now, another six weeks later, the car has suddenly started to shudder on pull-away.
Middelburg Audi is not sure what could be the cause, but they think it might be the torque converter going.
They tell me it takes a substantial amount of time to strip it and check. What do you suggest I do ? Louis
Motoring Guru replies:
I SUSPECT that a leak did indeed occur in the ATF cooling coils situated in the bottom (cool water) radiator tank of your Audi, Louis.
When that happens ATF will be forced out into the surrounding engine coolant while the engine is running, because while the ATF pump is operating the pressure in the ATF lines will exceed the pressure in the engine cooling system.
As the ATF level drops the point will be reached where the automatic transmission will start slipping because instead of feeding an uninterrupted supply of ATF to the torque converter, the ATF pump will now be delivering intermittent gulps of air.
The symptom of engine revs rising suddenly without a corresponding increase in road speed is typical of a slipping automatic transmission. (Other symptoms of a low fluid level are delayed gear changes and harsh engagement.)
In your case, where the slippage was caused by a leak in the ATF cooling coils inside the bottom radiator tank, one should also consider what happens when the engine is switched off.
The pressure in the ATF lines immediately falls away because the ATF pump is no longer operating. But the pressure in the engine cooling system remains effective (and even increases) because that's created by the thermal expansion of water. So now engine coolant is forced into the ATF lines, to be circulated through the automatic transmission when the engine starts up again.
Unfortunately water-soluble glue is used to assemble the clutch plates on most automatic transmissions, so any water contained in the ATF is bad news for an automatic gearbox.
The glue will come unstuck and that might manifest itself a few weeks later by juddering on pull-away. In your situation I suggest you shop around for a professionally reconditioned automatic transmission for your Audi.
VW-Audi might have factory reconditioned units for your car. They will be of unquestionable quality, but the price might be prohibitive.
Independent workshops will also have reconditioned boxes available, but here you are in landmine territory. You might get a unit that's good for 200000km or a spit-and-polish job that will last 10000km if you are lucky. Word of mouth is your best guide.
I discussed your query with a transmission expert. When I mentioned that your car was towed to Middelburg from Witbank, he interrupted me and asked, with finger raised, how was it towed?
The ensuing discussion again highlighted the vital importance of the fact that a car with automatic transmission should only be towed if the drive wheels are lifted clear of the ground, or, in the case of a rear-wheel-drive vehicle, if the propshaft has been disconnected.
Even a low-speed tow of 20km can wreck the lubrication-starved planetary gears.
The same guy observed that if ATF has leaked into your engine coolant, you will have to clean out the cooling system. He recommended using a well-known green-coloured detergent because it will not degrade the rubber components in the cooling system.
One also has to ask why rust occurred in the ATF cooling coils, and I can only surmise it is because the correct amount of anti-freeze and anti-corrosion additive was not used in the engine coolant.
Auto gearboxes are easily ruined, costly to replace
I OWN a 2005 Audi A4 2.0T AT, which I bought in April this year. On June 10, as I was going to work, the revs suddenly picked up without any increase in speed.
I reached my workplace but that was the end of the line for my automatic transmission. The car was towed from Witbank and taken to to Middelburg Audi.
It was inspected and they found that the transmission oil cooler in the bottom radiator tank was rusted and this had caused the Automatic Transmission Fluid (ATF) to leak out.
The price for fixing this was R10500. I contacted the warranty brokers, who were at first reluctant to assist me.
After I had harsh words with the warranty people (SA Warranties),they agreed to pay R4500.
The remaining R6000 I had to pay out of my own pocket - six weeks after I had bought the car. Now, another six weeks later, the car has suddenly started to shudder on pull-away.
Middelburg Audi is not sure what could be the cause, but they think it might be the torque converter going.
They tell me it takes a substantial amount of time to strip it and check. What do you suggest I do ? Louis
Motoring Guru replies:
I SUSPECT that a leak did indeed occur in the ATF cooling coils situated in the bottom (cool water) radiator tank of your Audi, Louis.
When that happens ATF will be forced out into the surrounding engine coolant while the engine is running, because while the ATF pump is operating the pressure in the ATF lines will exceed the pressure in the engine cooling system.
As the ATF level drops the point will be reached where the automatic transmission will start slipping because instead of feeding an uninterrupted supply of ATF to the torque converter, the ATF pump will now be delivering intermittent gulps of air.
The symptom of engine revs rising suddenly without a corresponding increase in road speed is typical of a slipping automatic transmission. (Other symptoms of a low fluid level are delayed gear changes and harsh engagement.)
In your case, where the slippage was caused by a leak in the ATF cooling coils inside the bottom radiator tank, one should also consider what happens when the engine is switched off.
The pressure in the ATF lines immediately falls away because the ATF pump is no longer operating. But the pressure in the engine cooling system remains effective (and even increases) because that's created by the thermal expansion of water. So now engine coolant is forced into the ATF lines, to be circulated through the automatic transmission when the engine starts up again.
Unfortunately water-soluble glue is used to assemble the clutch plates on most automatic transmissions, so any water contained in the ATF is bad news for an automatic gearbox.
The glue will come unstuck and that might manifest itself a few weeks later by juddering on pull-away. In your situation I suggest you shop around for a professionally reconditioned automatic transmission for your Audi.
VW-Audi might have factory reconditioned units for your car. They will be of unquestionable quality, but the price might be prohibitive.
Independent workshops will also have reconditioned boxes available, but here you are in landmine territory. You might get a unit that's good for 200000km or a spit-and-polish job that will last 10000km if you are lucky. Word of mouth is your best guide.
I discussed your query with a transmission expert. When I mentioned that your car was towed to Middelburg from Witbank, he interrupted me and asked, with finger raised, how was it towed?
The ensuing discussion again highlighted the vital importance of the fact that a car with automatic transmission should only be towed if the drive wheels are lifted clear of the ground, or, in the case of a rear-wheel-drive vehicle, if the propshaft has been disconnected.
Even a low-speed tow of 20km can wreck the lubrication-starved planetary gears.
The same guy observed that if ATF has leaked into your engine coolant, you will have to clean out the cooling system. He recommended using a well-known green-coloured detergent because it will not degrade the rubber components in the cooling system.
One also has to ask why rust occurred in the ATF cooling coils, and I can only surmise it is because the correct amount of anti-freeze and anti-corrosion additive was not used in the engine coolant.
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