HI folks

I'm looking for a little knowledge if there is anyone that can oblige.

I have a 2002 S60 2.4T with the auto tiptronic 5 speed box.

Unfortunately the car has been a little unloved by its previous owner, so limited funds spent on it in more recent years.

The issue I have is when driving the vehicle gently the 2nd to 3rd gear change is a little unusual. The change is slow with engine rpm rising by sometimes 1500 or so followed by a sudden bang in to third gear.

Not really noticeable when starting from cold though.

If I drive the car with a level of conviction there is no issue and if I floor the accelerator the car will go all through the gears no problem.

If I manually change; the issue is, there but if I change early (short shifting so to speak) no issue either.

The car is going in for a cam belt and water pump shortly and while there I will get them to change the gear oil and set to the correct level.

My question is,
is this an issue?
Is this possibly due to old gear oil,(being overly thinned!) possibly as old as the car (The car has only covered 60k but on a small island. Stop start stop start.)

Is it possible that new gear oil JWs3309 will sort the issue?

Any advice welcomed

Regards
M

 

have you looked at the color of the transmission fluid (should be reddish brown - not black) and confirmed the level is correct? (checking fluid levels can be tricky as the level changes as the transmission warms up). I think a drain/fill (or two) with fresh tranny fluid is a reasonable next step to see if it helps. Not sure why you suggested the old oil is overly thinned - had a prior owner had any servicing done to the transmission?

 

The oil is red-ish but getting dirty. (always difficult to tell the condition of gear oil when you only have the dipstick to go on, it contains so little that dirt seldom shows. draining is the real proof of condition.)

Level is a tiny bit low but not enough to bother it (I would think.)

To answer your question.
Oil has a viscosity level and this degrades over time from being worked, (or if you prefer sheared, over and over again.) And with heat. This causes thinning of the oil (aka loss in viscosity.) Which in turn lowers the oil pressure level.

When the car is driven with a little more conviction the engine rpm is slightly higher and thus so is the tranny gear oil pressure. (rpm related) (Hence the possible no issue when cold.)when the oil pressure drops, auto transmission can give issues. they rely on oil pressure to operate. No oil pressure, no drive.

My geographical location is one where the so called mechanics believe transmission and diff oils seldom require changing. National speed limit is outrageously slow, (to give you an idea, I could, if I wanted to, break the speed limit on a bicycle.) They are not taking in to account that wear takes place more-so while oils are cold and thus they neglect this area of a vehicle.

In all honesty, I very much doubt that the gear oil has ever been changed in its life of now 15 years. Hence the reason "I" will change it.

Just wondering if anyone knows if the issue is likely to disappear/relent once oil is changed?