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[Shackeng]

Thanks to BigGriffin, I have sourced a brand new AR35 which was purchased some (6?) years ago to fit to a Senny. This is going on my TD to replace the, supposedly, re-furbished one that ate its thrust washer. Apart from the bell housing and torque converter, are there any other Senny only bits which will need swapping?
Also, as this box was bought from Germany at a cost of £660, this suggests that it may be older than 6 years. If so is it likely to have been fitted with the later, more robust thrust washer?
I am thinking that it may be sensible to strip and fit a Sonnax washer before fitting.
Any thoughts?

[Kevin Wood]

I have a recollection that the wiring is all different on the Senator, so probably worth keeping the internal looms and connectors from the old one. Not sure on the thrust washer, but if you've got to swap bellhousings anyway, you might as well, IMHO.

[biggriffin]

Deleted due to writing piffell 

[Diamond Black Geezer]

I know preventative maintenance is often a hugely useful thing, but surely having acquired a brand new box, you should be trouble free for a great many years to come. I completely take your logic, but I'd say fit and forget. But, it won't do any harm to fit one, of course. When I fitted brand new wishbones, I gave them an extra couple of coats of paint, no reason, other than 'why not? can't hurt'

[Shackeng]

Those are my thoughts also, as the bellhousing has to come off anyway, its not much more to replace the thrust washer, and, I have an unwanted AR25 on which I can practice first!
 Kev, I'm trying to remember what electrickery, apart from the selector which will have to be fitted, is involved. I certainly will be concerned if I have re-build the internal electrics.

[Shackeng]

From what Kevin says above, it seems that the box may be somewhat different internally. I am now getting cold feet.

[Diamond Black Geezer]

As I understood it, though annoyingly both called AR25 / AR35, the Omegas AR25/35 is slightly different (the wiring etc you mention) and fitting the one in the other is a pita... I'm assuming you've got some extra info over me with regard to fitting them? If so would perhaps be nice to see a howto appear in the future? (Not that many people finding NOS Senny gearboxes for their Omegas, but the practice in reverse may be of great use to Carlton / Senator owners) ? 


Edit: don't get cold feet, it's doable as far as I've heard, just requires some research and 'measure twice cut one' methodoly 

[Shackeng]

As I understood it, though annoyingly both called AR25 / AR35, the Omegas AR25/35 is slightly different (the wiring etc you mention) and fitting the one in the other is a pita... I'm assuming you've got some extra info over me with regard to fitting them? If so would perhaps be nice to see a howto appear in the future? (Not that many people finding NOS Senny gearboxes for their Omegas, but the practice in reverse may be of great use to Carlton / Senator owners) ? 


Edit: don't get cold feet, it's doable as far as I've heard, just requires some research and 'measure twice cut once' methodoly 

I agree with your last comment. The current box in my TD is an AR35, and was a direct swap for the old 25 sitting sadly under my bench. Nothing at all was required electrically, it was a straight swap, with just the bell housing and torque converter required. Box has worked OK for the 17k since fitting until acting strangely recently which turned out to be the thrust washer. Annoyingly it was sold to me as 'Refurbished 12k ago'. Hmmm, must have been a very hard 12k.
I'm now wondering if even the gear ratios are likely to be the same, or are these determined by the electrickery? (Shows how much I know about auto boxes  )

[Diamond Black Geezer]

Seem to think the ratios are identical, sadly my brochures are all packed away at my parents, but have a neb at the ABS website, they have some detail info from the brochures. 

[aaronjb]

I'm now wondering if even the gear ratios are likely to be the same, or are these determined by the electrickery? (Shows how much I know about auto boxes  )

Ratios are determined mechanically via the planetary gear sets, which gear you are in is determined by the solenoids 'locking' gear sets via brake bands.

This video should explain everything*: https://www.youtube.com/watch?v=-FyC3dn3HJY

*It won't, it really won't, but it's very neat nonetheless. Automatic gearboxes are still magic and fairydust to me.

[Shackeng]

Seem to think the ratios are identical, sadly my brochures are all packed away at my parents, but have a neb at the ABS website, they have some detail info from the brochures. 

Just checked, they are the same except
Reverse: Omega=2.00:1, Senny 1.92:1

I don't see that as a problem.

[Shackeng]

I'm now wondering if even the gear ratios are likely to be the same, or are these determined by the electrickery? (Shows how much I know about auto boxes  )

Ratios are determined mechanically via the planetary gear sets, which gear you are in is determined by the solenoids 'locking' gear sets via brake bands.

This video should explain everything*: https://www.youtube.com/watch?v=-FyC3dn3HJY

*It won't, it really won't, but it's very neat nonetheless. Automatic gearboxes are still magic and fairydust to me.

This is the bit that concerns me, as presumably given the different power outputs of Senny straight six vs Omega V6 this may affect speeds at which gears change. Having said that, the Ar35 in my TD appears to behave the same as the old AR25 I took out.

[Steve B]

Just a thought.. you could give this bloke a ring and see if he can shine any light on your thoughts.
I was in there a few years ago talking to him about AR25 and solenoids and he seemed clued up on the omega box...

http://www.mechanicalworkshop.co.uk/

[aaronjb]

This is the bit that concerns me, as presumably given the different power outputs of Senny straight six vs Omega V6 this may affect speeds at which gears change. Having said that, the Ar35 in my TD appears to behave the same as the old AR25 I took out.

IIRC the speed of change is related to the hydraulic pressure routed to the brake bands via the solenoids; that should be a function of both pump and software (the solenoids are likely PWM'd).. a bigger concern would be whether the pressure applied would be enough to lock the gearset and whether the brake bands are capable of doing so..

IIRC the 24v was pretty comparable to the later V6 though in power and torque?

[Kevin Wood]

The shifting behaviour is all electronically controlled by signals to the solenoids, as said, and you'll be keeping the Omega's ECU, so no problems there.

What you might find is that some of the connectors and wiring are different. You'll have everything you need on the old box and I'd imagine it'll swap straight over. All I'm reporting is heresay, however, so please don't take it as gospel. Autobahnstormers would probably be the place to ask for definitive information.