Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: Shackeng on 02 July 2016, 15:26:44

Title: Autobox thrust washer failure.
Post by: Shackeng on 02 July 2016, 15:26:44
Removed the sumps on the TD to clean the filter and change the oil due to unwelcome gear box performance, in the front sump I discovered what I assume are the remains of the thrust washer. I am very disappointed as this AR35 has only done 15k in my ownership, and I was advised that it was originally an AR25 that had been rebuilt as an AR35.
What causes these washers to fail, given that I cannot be accused of thrashing the car?
My AR25 did 115K without any problems, and I may have to refit it if replacing the washer is a task too far.
Any comments on the above from those with experience of this failure welcome.
Title: Re: Autobox thrust washer failure.
Post by: Andy H on 02 July 2016, 16:08:05
I think the original washers were plastic and the revised washers are metal. Do you know if the revised washer was fitted to yours when it was rebuilt?

If you still have the plastic one I am guessing that age and heat are significant factors in when the washer disintegrates :-\

I have a 2003 V6 2.6 with what I assume to be the original AR25. At 190,000 miles reverse started to get slow to engage. I dropped the sumps but didn’t find anything untoward (no washer fragments and the fluid level was OK) so I cleaned the sumps, fitted a new filter and filled up with new fluid. It didn't make any difference to the changes. The car passed 210,000 miles yesterday. Reverse is slower to engage now but it still works (eventually) so I think my AR25 is pretty well worn out.

I assume that the Diesel exerts greater shock loads through the drive train & the plastic thrust washer is the weakest link :-\
Title: Re: Autobox thrust washer failure.
Post by: Shackeng on 02 July 2016, 16:14:35
Thanks Andy, yes, slow engagement of movement in reverse is one of my symptoms, but as I said above, this seems very strange to fail after 27k, given my sedate driving style, even with the chipped ECU. I doubt I have floored the pedal half a dozen times in the last five years.  It is a beige plastic type washer, and came out in several bits. What damage is likely to occur if driven without the washer? Given that I have no idea how long it has been failed, although it has only been dubious in operation for 6 months or so.:-\ :-\ :-\
Title: Re: Autobox thrust washer failure.
Post by: Shackeng on 02 July 2016, 16:30:49
The sumps will have to go back until I decide what to do. Since it still worked, if not brilliantly, before I took them off, it should still work for a bit longer. :y
Title: Re: Autobox thrust washer failure.
Post by: biggriffin on 02 July 2016, 16:32:30
I don't know if the updated washer is available (sonnax)
Title: Re: Autobox thrust washer failure.
Post by: steve6367 on 02 July 2016, 17:17:57
I don't know if the updated washer is available (sonnax)

When I did mine recently I could not get it in a sensible time scale so fitted a new plastic - I decided that if the original lasted 14 years and 100K a new plastic would do me  :y
Title: Re: Autobox thrust washer failure.
Post by: Scatmancraig on 02 July 2016, 18:01:17
I have a 2.5 TD (standard ECU) with AR25 fitted, the car is on 163k but the gearbox is on about 90k as the original was replaced when it was still a company car.  Mine is slow to engage reverse too, but goes forward ok.  I'm going to change the fluid and filters on my box in the next few weeks, so I'm hoping I don't find any bits in the sump!! 
Title: Re: Autobox thrust washer failure.
Post by: Andy H on 02 July 2016, 19:22:42
Jpat http://www.jpat.co.uk/Products.html (http://www.jpat.co.uk/Products.html) used to be the recommended supplier and they still list Sonnax as being one of their suppliers.

This www.sonnax.com/parts/2182-thrust-washer-shim-kit (http://www.sonnax.com/parts/2182-thrust-washer-shim-kit) appears to be the kit you require.
Title: Re: Autobox thrust washer failure.
Post by: steve6367 on 02 July 2016, 19:44:17
Jpat http://www.jpat.co.uk/Products.html (http://www.jpat.co.uk/Products.html) used to be the recommended supplier and they still list Sonnax as being one of their suppliers.

This www.sonnax.com/parts/2182-thrust-washer-shim-kit (http://www.sonnax.com/parts/2182-thrust-washer-shim-kit) appears to be the kit you require.

JPat could not supply when I asked - they did supply the plastic though and I don't expect the car to still be functioning in another 100K
Title: Re: Autobox thrust washer failure.
Post by: Andy H on 03 July 2016, 08:28:09
I thought there was a thread describing what happens when the thrust washer fails but I haven't found it. :-\

What I have found is a guide to fitting a new one Autobox - THE dreaded thrust washer explained (http://www.omegaowners.com/forum/index.php?topic=90554.msg1155422#msg1155422)
Title: Re: Autobox thrust washer failure.
Post by: steve6367 on 03 July 2016, 08:42:27
I thought there was a thread describing what happens when the thrust washer fails but I haven't found it. :-\

What I have found is a guide to fitting a new one Autobox - THE dreaded thrust washer explained (http://www.omegaowners.com/forum/index.php?topic=90554.msg1155422#msg1155422)

Ones the whole washer disintegrates I would imagine to the 2 metal surfaces contact each other and its game over fairly quickly!
Title: Re: Autobox thrust washer failure.
Post by: Shackeng on 03 July 2016, 10:18:19
I thought there was a thread describing what happens when the thrust washer fails but I haven't found it. :-\

What I have found is a guide to fitting a new one Autobox - THE dreaded thrust washer explained (http://www.omegaowners.com/forum/index.php?topic=90554.msg1155422#msg1155422)

Thanks, it was the first thing I read. :y
Title: Re: Autobox thrust washer failure.
Post by: Shackeng on 03 July 2016, 18:02:00
Test drive today, box now behaving perfectly.??? :-\ However, given that it is now running without a washer, I have located an AR35 locally, so the plan is to buy that, £150, replace the thrust washer, hopefully with the later Sonnax type, and get my local friendly garage to swap it into the TD. I can then replace the washer on the one currently in use, and keep it as spare. :y
Title: Re: Autobox thrust washer failure.
Post by: RobG on 03 July 2016, 18:44:43
Thanks Andy, yes, slow engagement of movement in reverse is one of my symptoms, but as I said above, this seems very strange to fail after 27k, given my sedate driving style, even with the chipped ECU. I doubt I have floored the pedal half a dozen times in the last five years.  It is a beige plastic type washer, and came out in several bits. What damage is likely to occur if driven without the washer? Given that I have no idea how long it has been failed, although it has only been dubious in operation for 6 months or so.:-\ :-\ :-\
Pump face will need machining if driven for long periods plus the extra play in input shaft would possibly damage other internal components.
Title: Re: Autobox thrust washer failure.
Post by: Shackeng on 03 July 2016, 22:28:17
Thanks Andy, yes, slow engagement of movement in reverse is one of my symptoms, but as I said above, this seems very strange to fail after 27k, given my sedate driving style, even with the chipped ECU. I doubt I have floored the pedal half a dozen times in the last five years.  It is a beige plastic type washer, and came out in several bits. What damage is likely to occur if driven without the washer? Given that I have no idea how long it has been failed, although it has only been dubious in operation for 6 months or so.:-\ :-\ :-\
Pump face will need machining if driven for long periods plus the extra play in input shaft would possibly damage other internal components.

Thanks Rob, plan to replace it in hand. :y