VW Golf 2001 Mk4 1.6 - Auto Box slipping

[Transmitter Man]

My wifes grocery getter changes gear fine but in top above 2,000 rpm the engine starts to rev and gives the impression there's suddenly no drive between auto box and wheels!

Is it common for 3rd gear clutches/bands to wear out with 1st & 2nd still reasonably OK.

Could this be low fluid?

Are the clutch bands adjustable externally and would this help at all?

Or, am I looking at a box rebuild?

Your thoughts please?

Phil

[E-bmw]

Start with a fluid/filter change on the transmission.

[Transmitter Man]

Thanks.

Planning that in the next couple of days.

[hedges88]

Transmitter Man said:

My wifes grocery getter changes gear fine but in top above 2,000 rpm the engine starts to rev and gives the impression there's suddenly no drive between auto box and wheels!

Is it common for 3rd gear clutches/bands to wear out with 1st & 2nd still reasonably OK.

Could this be low fluid?

Are the clutch bands adjustable externally and would this help at all?

Or, am I looking at a box rebuild?

Your thoughts please?

Phil

So from what I remember they are a pretty simple old 3 speed and overdrive slushy, A0? maybe

As said checking fluid levels and quality is your first priority, I don't know if they have a dipstick located under the bonnet. If it does the manufacturer might want the level checked in various ways, for example some want the box to be hot and in N, not P for checking the fluid level. Dipstick or not, fluid levels and quality will be the focus of your attention for now. The fluid is supposed to be nice and red. On an old and worn but well maintained auto you should at least expect it to be pinky with a minimal amount of darkening. If the fluid is extremely dark and has a large amount of deposits in it then a complete change of fluid could potentially be the end of the gearbox as essentially if the brake bands and clutches are very worn the friction material in the ATF fluid might be all that's helping them hold. Also fluid changes are a problem, even if you drop the pan there's still so much fluid held in the converter and if there's no drain plug you essentially renew the fluid over the course of hundreds of miles by draining and replacing time and again. There's also usually a magnet in the pan which should be inspected for metallic deposits (a small amount is normal) before being cleaned. If you do end up doing a fluid change in the way I've described use cheap (but manufacturers spec!) ATF fluid and cheap pattern part filters before going for the real good stuff and OEM filter on your final dilution based renewal of the fluid.

In answer to your other questions, firstly you'd expect slipping between first and second and problems with no drive in reverse gear to rear their head first. The third gear though has the stress of dealing with being paired with the overdrive unit and over the years that can take a toll. Brake bands and clutches are internal and nothing is really adjustable from the outside of the unit. Problems with momentary slipping into third gear but no problems with reversing, no knocking or banging or jerky shifts in other gears could hopefully just be poor fluid quality or level causing problems with actuation of the valve body rather than serious internal wear to the bands and clutches hopefully!

If the fluid is nasty and contaminated, bearing in mind the age and value of the vehicle is see how far you get with using a product called Lucas Stop Slip. It's held the autobox in the family pool Hyundai together for about 3 years 😅. A 3 speed box with such a small engine in a fairly heavy car is going to be relying on using the converter a lot for torque multiplication because there's just not enough ratios to play with for daily driving. That point of where the engine speed is advancing ahead of the road speed is where the fluid is subjected to high temperatures and forces so unfortunately you can expect that box to be in a bad way if it's never been properly serviced. Also if you're wife is doing the groceries in it then the low speed urban traffic amplifies the problem of the stress of being in that state, as well as continually being in a situation of being stationary where the fluid is being thrown from the turbine, meeting a stationary impeller and being forced back through the stator. Lots of heat, lots of pressure, lots of stress thus lots of burning fluid that breaks down and looses it's properties.

Seeing if VAG were still putting an ATF dipstick under the bonnet in the early noughties is what I'm waiting to hear on 👍 Maybe the sealed for life planned obsolescence hadn't started by then 😅

[Transmitter Man]

OK, thanks for your patience :-)

After a filter and fluid change in the 4-sp (or 3 + OD) auto it's better but only by 10% and still has the effect of jumping out of 4th with the rev's increasing.

I get the impression it's the first ATF change and or top-up in a very long time.

As this work was carried out by one of the local indies prior to your post I was unable to pass on your thoughts. I hear what you say regards typical use of this box in a shopping car for constant stop & start use. There is no external dipstick.

So, it looks like a good used replacement or a rebuild kit and therefore a complete stripdown. In situations like this buying a used box I think is falsev economy as what guranteev is there it's not a lemon - none.

A local dealer has one with 85K on it. I don't believe that figure and he's asking 550. Which of course is whole deal lesss costly that a replacement box 3K. So, that just leaves a full rebuild kit. Circa 400 quid + I'm sure at least 500 for the labour. but one has to ask how good are these kits compared to those in the original factory build? Best try to find a half decent rebuilder?

Or, any further thoughts?

[Chiswickboy]

Seeing if VAG were still putting an ATF dipstick under the bonnet in the early noughties is what I'm waiting to hear on 👍 Maybe the sealed for life planned obsolescence hadn't started by then 😅

My 1999 Golf does not have a dipstick. The ATF is checked via a level plug in the centre of the drain plug.

From memory, the car needs to be driven to warm up the fluid, then the level plug is removed and fluid should drip out if the level is correct. If no fluid drips it needs topping up (or better still, draining and refilling with new) and if it runs out there is too much.

These boxes are "sealed for life" which is sales speak for not being a routine / scheduled service item. The sump contains a filter which should ideally be changed and also a magnet to collect particles which should be cleaned when doing a fluid change.

Edited by Chiswickboy on Tuesday 10th August 13:40

[Transmitter Man]

Bit of a delay in responding but here goes. No ATF dipstick on the car. Have changed fluid & filter, unfortunitely to no avail. The problem persists and even when driven from cold it will jump out of O/D within 5-10 minutes max. Will a diagnostics pickup anything such as a sticky valve in the valve body? I imagine one would have to take it for a drive with the indy's computer plugged in for anything to show? At this point it is looking at a gearbox out job. I don't like to be beaten and would prefer to persevere to sort this out and get a few more years out of the old girl - even if it costs. Your further thoughts as to the next step? Thanks.

[GreenV8S]

If you can find a transmission specialist it would be worth getting their take on it. I know that some problems like this can be fixed by dropping the sump and servicing the valve assembly without removing the transmission, but I have no idea whether that's possible or worth trying here.