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[Steve B]

looking for feedback from anyone who has ever experienced these faults with a autobox,

surely im not the only one to have this problem ar25 auto box


i need to point out that the fluid was fully replaced within the last 48 hours

when the fluid was taken out iirc there was approx 4.5ltrs when it was refilled i think 6.5ltrs went

in..therefore it was clearly low


the firmware in the box is fully up to date within the last 48 hours

the car is a 2.2cd petrol with 53 on the clock


i need to point out that the 2 faults were there before the atf was change and updates were done.

and it is not the gear selector on the side of box.

there are no fault codes at all i am fully clean (no eml)

and here is the prob.....

(1)going along 20 mph ,foot lightly on throttle..lift it off and then(thud) a kick in the back...(feels like you

have just been hit from behind..IE (slight hit)

(2)going along 20mph foot lightly on throttle....then suddenly car revs like it has just had clutch dipped,
take your foot off gas pedal and all is normal again(but its a auto)

HAS ANYONE EVER HAD ANY OF THESE PROBLEMS......

[Steve B]

.

[The Red Baron]

looking for feedback from anyone who has ever experienced these faults with a autobox,

surely im not the only one to have this problem ar25 auto box


i need to point out that the fluid was fully replaced within the last 48 hours

when the fluid was taken out iirc there was approx 4.5ltrs when it was refilled i think 6.5ltrs went

in..therefore it was clearly low


the firmware in the box is fully up to date within the last 48 hours

the car is a 2.2cd petrol with 53 on the clock


i need to point out that the 2 faults were there before the atf was change and updates were done.

and it is not the gear selector on the side of box.

there are no fault codes at all i am fully clean (no eml)

and here is the prob.....

(1)going along 20 mph ,foot lightly on throttle..lift it off and then(thud) a kick in the back...(feels like you

have just been hit from behind..IE (slight hit)

(2)going along 20mph foot lightly on throttle....then suddenly car revs like it has just had clutch dipped,
take your foot off gas pedal and all is normal again(but its a auto)

HAS ANYONE EVER HAD ANY OF THESE PROBLEMS......

could it be the dreaded thrust washer thats fell into the sump in bits.

[Steve B]

why do you say that red baron

[The Red Baron]

im no auto box expert but im pretty sure that a rather common thing is that the thrust washer fails, giving you the thump, the bits are usually found in the sump area of the box. no doubt others will confirm/deny.

[JamesV6CDX]

We drained the oil using sassanach's method - EG pumping out of the cooler pipe, filling with new, pumping again, until it ran red - to flush it all through, and replace the oil in the TC, Gearbox cooler etc as much as possible.

The box was desperately low on oil - by about 2 litres.

Whilst I agree that the thrust washer can sometimes cause the thud (it didn't on mine, though!) I can't see this cuasing the loss of drive at 20mph when accelerating.

I can only imagine this could be the torque converter  maybe damaged through low fluid?

This box has historically leaked from the prop seal..  which I would imagine would account for why the fluid was so low when we looked at it.

[amba]

I have the exact same problem with mine..Also the AR25...fluid has been replaced by dropping both sumps and renewing filter screen and getting back in around 6 ltrs of Dexrom III.No eveidence of amything was found in either sump.

After fluid change box was smoother but seems to hang in the change between 2-3 more often coming down the box,but does also do it sometimes going from 2nd into 3rd automatically..This can be confirmed by putting box manually into 2nd and then at around 2500rpm,s changing into 3rd manually.It seems to hold 2nd then "thud" from the rear end when 3rd eventually engages.

Have also had the "lost drive effect" where no drive is found then engine revs wildly .This can be restored by lifting of and coasting until enaged again.I have also syringed off a further 2 ltrs of fluid and replaced with new again in the hope that it may have been low but this has had no efect either.

It was suggested that it could be a solenoid possibly the 2/3 which a very kind OOF member has supplied me with a full set from and old box,however as yet due to weather and work commitments I have not had the opportunity to replace but am still undecided as it has only ever registered a "Gearbox Fault" a couple of times and with the extra cost of a further 10ltrs of AFT I am still deciding the best cours of action.

Car has covered 205k and has been maintained to a high standard. ATF has been replaced twice in my 140k ownership and each time Dexron III has been used and no sump contamination or debris has been found.

Will follow this post progress with interest 

[kcl]

What version of software is installed to gearbox ECU?

[Kevin Wood]

Any codes present in the gearbox ECU?

Torque converter is just a couple of turbines in a housing, so very unlikely it has a problem. Sounds like a hydraulic / electrical issue to me. Intermittent electrical connection or failing solenoid perhaps?

[amba]

Firm wear in my box was done by Kevin about 3 years ago shortly after it had a previous fluid and filter change at around 135k.

Problem with mine has been getting progressively worse although it doesn,t do it all the time ,but perhaps I have just got used to driving it to stop the problem with engine /speed changes.

Assume that it is possible to identify if a solenoid is playing up via Tech 2.Have had "Autogearbox Fault " warning appear around 3-4 times over the last year and then goes straight to limp mode so imagine something registered would be stored somewhere.

Box is smooth through gears and has no noises when changing.Have noticed,and this may be complety unrelated but when braking hard from say 30 ish get a noise like..." somebody is holding an old fashion spinning top and slowing it by hand" is the best way I can describe it or like being slowed by something holding it....if that makes sense.

Not sure if Bigtimecube has experienced similar issues with his AR25 as don,t want to appear I am hijacking his original post although our symptoms sound similar.

[Marks DTM Calib]

Just to add, software was updated from 4 to 10 and no fault codes are present. My thoughts were a sticking 2-3 solenoid or failed thrust washer giving reduced oil pressure.

[JamesV6CDX]

Just to add, software was updated from 4 to 10 and no fault codes are present. My thoughts were a sticking 2-3 solenoid or failed thrust washer giving reduced oil pressure.

When we pumped out the oil it was certainly under a lot of pressure - and given the lurch on slowdown at 20mph odd, I am leaning towards the solenoid....

[JamesV6CDX]

I would add though mate, get the MOT done, and anything required for that... worry about the autobox afterwards

[Steve B]

I would add though mate, get the MOT done, and anything required for that... worry about the autobox afterwards

i agree james.....and that is at 2pm today

hate going to mot,s you never no what your gonna get

[JamesV6CDX]

I would add though mate, get the MOT done, and anything required for that... worry about the autobox afterwards

i agree james.....and that is at 2pm today

hate going to mot,s you never no what your gonna get

Keep us updated as to the result mate