Whining noise after towing the caravan?

[ywork Member Find all posts View Profile Close ywork]

My 4l V6 grande has now got 230000 on the clock and never missed a beat. Did full oil change 3000 km ago, all oils front / back diff and transfer case also the transmission oil done at Toyota?
We went away on holiday with the caravan for two weeks and had no issues at all with the Prado. But since we back, I have noticed a slight whining noise when accelerating in 1-2 gear. Seems to be loudest at the higher rev range and coming from the auto transmission. This is new and only since we got back from towing the caravan. Is this something to be concerned about? The caravan was well within the towing weight at around 1900kg and did not find the Prado to be laboring to tow it.

[cuda Advanced Member Find all posts View Profile Close cuda]

Have you been towing the caravan in D or 4th? Cant blame the tranny oil for being old since it was replaced.

[t303 Senior Member Find all posts View Profile Close t303]

Have you been towing the caravan in D or 4th? Cant blame the tranny oil for being old since it was replaced.

Good question Cuda.
Ywork, I'm not familiar with the auto; can you check the colour and smell of the fluid on the dipstick, or drop some out? Stuffed ATF will have a distinct burnt smell and will be dark.

[ywork Member Find all posts View Profile Close ywork]

Cuda, towing in D all the time my Prado is auto and only the 4 speed model. I checked the ATF it looks ok to me and no real smell that I notice its done 3000 km on the new ATF oil. Looks like a light red brown colour. May get someone to check the transfer box could this cause a whining noise at all..?

[t303 Senior Member Find all posts View Profile Close t303]

Cuda, towing in D all the time my Prado is auto and only the 4 speed model. I checked the ATF it looks ok to me and no real smell that I notice its done 3000 km on the new ATF oil. Looks like a light red brown colour. May get someone to check the transfer box could this cause a whining noise at all..?

Bit hard to tell when it is soaked into paper towel, but ATF that old I would expect to still be a red colour with no brown (assuming DEXII or III). Can you photograph a quantity on a piece of white plastic or something? If it was transfer I would expect to hear it in all gears. Was it hot weather towing? In any event I would be adding an oil cooler in front of the aircon condensor if you plan to tow regularly. I even have one fitted to the power steering circuit to stop the fluid going off and overheating the seals in the system.

[ywork Member Find all posts View Profile Close ywork]

Hi T303,yes my Prado has a small radiator in the front for the ATF and a warning icon that's only every come on once whiles beach driving on Fraser a few years back. Was not hot weather and the warning icon for AT temp did not come on. Im starting to think its not the ATR the noise is in all gears but worst on pull away
that's the only time you hear it clearly.

[t303 Senior Member Find all posts View Profile Close t303]

Do you know what oils were used in the diffs etc? A lighter weight oil might give you slightly more noise.

[ywork Member Find all posts View Profile Close ywork]

The Rear diff - CASTROL SYNTRAX 80W-140 Transfer -CASTROL SYNTRAX UNIVERSAL PLUS 75W-90 Front Diff - CASTROL AXLE EPX 80W-90

These were the oils used, just find it odd that the noise only started now as have towed my van and my boat a few times before hand.