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Omega Help Area => Omega General Help => Topic started by: Rog the Dodge on 22 February 2010, 23:03:01

Title: ex plod manual gearbox
Post by: Rog the Dodge on 22 February 2010, 23:03:01
It is looking like i need to replace my gearbox very soon .
The box in it is a R25 R28 , i have seen that there are a few around ,but i think i read somewhere on this forum that plod had something different ,my question is can i put a replcement R25 R28 straight in ???
Title: Re: ex plod manual gearbox
Post by: tunnie on 22 February 2010, 23:08:14
R28 & R25's are separate boxes, the box in yours will be an R28, R25 is fitted in 2.5's 2.0's

Any R28 should be ok  :y
Title: Re: ex plod manual gearbox
Post by: Rog the Dodge on 22 February 2010, 23:15:09
ok, i am sure when i looked it had both written on the side of the box, but it was dark and bloomin cold.and my candle did keep flickering ,lol
So need to find a R28,what other vauxhalls was this box in?
Title: Re: ex plod manual gearbox
Post by: tunnie on 22 February 2010, 23:19:25
not many, Veccy had F28 (front wheel drive), sourcing an Omega one is your best bet
Title: Re: ex plod manual gearbox
Post by: Rog the Dodge on 22 February 2010, 23:25:30
ok thanks for the info, i can now search for the correct gearbox, not many 3.2 manuals around in the scrap yards???
Title: Re: ex plod manual gearbox
Post by: Rog the Dodge on 22 February 2010, 23:35:50
i have just seen this one on ebay,380181947390, is that the correct one for mine ?
Title: Re: ex plod manual gearbox
Post by: RobG on 22 February 2010, 23:38:23
Nope. That`s the R25 Rog. If you give the chap a ring (Steve) tell him your from OOF he may be able to source one for you.
Title: Re: ex plod manual gearbox
Post by: Rog the Dodge on 22 February 2010, 23:46:19
ok Rob, cheers for that, i was a little unsure with the listing when it said R25 - R28 ???
I will give them a ring in the morning ,i may get mine rebuilt,at least then i know its the correct one,lol
Title: Re: ex plod manual gearbox
Post by: serek on 23 February 2010, 00:02:56
Quote
It is looking like i need to replace my gearbox very soon .
The box in it is a R25 R28 , i have seen that there are a few around ,but i think i read somewhere on this forum that plod had something different ,my question is can i put a replcement R25 R28 straight in ???
why you think your gearbox need replace???
Title: Re: ex plod manual gearbox
Post by: U on 23 February 2010, 08:00:25
for exploded view - just take a look at EPC.
Title: Re: ex plod manual gearbox
Post by: Rog the Dodge on 23 February 2010, 08:40:15
Really noisey in 1,2 and reverse, getting worse with every mile, so i think i am on borrowed time.
Took it to my local triendly garage who confirmed it is an issue within the rear of the gearbox.
I have made a few calls but it seams like they are like hens teeth.lol
Title: Re: ex plod manual gearbox
Post by: Rog the Dodge on 23 February 2010, 21:50:23
After a few phone calls today, and a visit to my freindly vx dealer, i have learnt that a gearbox from a DTI diesel 2.2(which also has the R25-R28 on the side of the housing!!!) will also fit my car, all i need to do now is find one ???
Title: Re: ex plod manual gearbox
Post by: tunnie on 23 February 2010, 21:55:51
Quote
After a few phone calls today, and a visit to my freindly vx dealer, i have learnt that a gearbox from a DTI diesel 2.2(which also has the R25-R28 on the side of the housing!!!) will also fit my car, all i need to do now is find one ???

How aggressive do you drive? You do really need an R28, but an R25 would cope.
Title: Re: ex plod manual gearbox
Post by: Rog the Dodge on 23 February 2010, 22:03:41
Not that aggresive,lol
But if thats the box it should have, then thats the box it will have, when i find one !
Title: Re: ex plod manual gearbox
Post by: tunnie on 23 February 2010, 22:07:29
Quote
Not that aggresive,lol
But if thats the box it should have, then thats the box it will have, when i find one !

I have in the past said always go R28, but because a manual (unlike an auto) only needs to change gear for just a second, you can get away with a weaker box.

AR25 will be shreded by a 3.0 in seconds, but R25 would last ok. (unless on a track)

They are separate boxes though, not sure why they are labeled 'R25 R28'  :-/
Title: Re: ex plod manual gearbox
Post by: tunnie on 23 February 2010, 22:41:39
looks like Darth still has one for sale....

http://www.omegaowners.com/forum/YaBB.pl?num=1266936728
Title: Re: ex plod manual gearbox
Post by: Rog the Dodge on 23 February 2010, 22:46:44
will that fit in mine then ?
Title: Re: ex plod manual gearbox
Post by: MutantCav on 23 February 2010, 22:47:58
I have one here (R28). Just about to break my manual 3.0 estate...never worked out myself why the R28 boxes have as you say r25/r28 on them...very confusing!
Title: Re: ex plod manual gearbox
Post by: Rog the Dodge on 23 February 2010, 22:55:14
when are you looking to break it?
Title: Re: ex plod manual gearbox
Post by: JasonH on 23 February 2010, 23:03:07
The outside of the gearbox is the same moulding for an R25 or an R28 so that's cast into the housing, i.e. this can be an R25 or an R28. There's no obvious clue to which one it actually is.
Title: Re: ex plod manual gearbox
Post by: Rog the Dodge on 23 February 2010, 23:14:23
i knew there had to be an explanation,thanks for that info, so the next question is how are you going to know what is in what???
That would explain why some of the breakers that i have emailed might not be answering due to the fact that they dont know either, well maybe,they could just be busy lol
Title: Re: ex plod manual gearbox
Post by: ffcgary1 on 24 February 2010, 00:31:56
you have pm :y
Title: Re: ex plod manual gearbox
Post by: MutantCav on 24 February 2010, 07:26:52
Will be breaking it this week mate :y
Title: Re: ex plod manual gearbox
Post by: tunnie on 24 February 2010, 09:40:03
Quote
The outside of the gearbox is the same moulding for an R25 or an R28 so that's cast into the housing, i.e. this can be an R25 or an R28. There's no obvious clue to which one it actually is.

The true ident is on a metal plate, passenger side front of the box up quite high, looks almost like a dog tag  :y
Title: Re: ex plod manual gearbox
Post by: Rog the Dodge on 24 February 2010, 11:00:27
Thanks mate, thats the info i really needed, i take it then that once i have all the info off the dog tag look a like i can then match it up, all the boxes i have found(from breakers!!!) just say its a R25-R28 ,and it SHOULD fit.
Dont suppose you would happen to know what my plate should read, as i am at work at the moment,cant check it until later
Thanks in advance.
Title: Re: ex plod manual gearbox
Post by: 2woody on 24 February 2010, 20:54:09
just for reference, both the R25 and the R28 are actually Getrag 240 transmissions made for GM.

I think the difference is probable shot-peened gears for the R28. Based on a whole lot of research I did a while back. Theoretically, the R28 is able to handle more torque, but both the bearings and the synchros are the same. So it looks like shot-peening the gears must be the only thing that could have been done to improve the capacity.

I have a standard 2-litre gearbox in a 3.0 V6 track-day car that has withstood these loads for five years now, so I think youll be fine with either, provided you don't do a lot of maximum trail-weight towing