R25 Manual gearbox conversion

deja vu 25

deja vu 25

Active member
Fellow Frogger
Joined
Jan 22, 2002
Messages
657
Location
Canberra
Hi All,

Has anyone converted an auto R25 to a UN1 5-speed manual (the hydraulic clutch)?

After waiting almost 8 years, I have just acquired myself a manual gearbox and wish to do the job. I need to know if there is anything to be aware of, or any mods I may have to do. I am hoping that it is a straight pull off, put on sort of job?

Any hints/tips/info would be mucgh appreciated.

Many Thanks

Luke
 
Yes I have, did my wifes car a few years ago, drove it to work Saturday morning as an auto and drove it home Sunday night as a manual, completly on my own, the only hard part was the top bolt above the clutch pedal under the dash, I would have been driving it Saturday night if it wasn't for that one bolt.

David.
 
I don't have any tips for you Luke, but it will be interesting to hear what you come up against.

I assume you would need a different pedal box (or is the clutch pedal mounting bracket seperate?) plus of course gear lever, linkages, interior trim and gearbox mounting brackets - I wonder if the mounts themselves are different?

Let us know how you go!
 
Hi Luke,

How did you come upon the gearbox....how many toothless hens are in the Tuggeranong Valley?

Is that dud manual 25 still in Fyshwick?

Is the Pope a Catholic? does a R19 backfire in the woods???

Please answer these meaning of life questions...

That aside, it's great news that you have located a suitable box...now for that V6
 
Hi All

Thankyou for the advice, words etc.

I am glad to hear from Dave that it should not cause me too much grief. He is probably more experienced than I am though.

I will keep people updated with the progress. I have to buy a new clutch kit - does anyone know what they are worth? (it is Valeo)? And does this kit have all the seals/gaskets etc necessary for the job?

The dud manual is still out in Fyshwick, and it will stay there unless they are happy to take serious offers. I made the guy an offer on it and he said that his boss wouldn't let him do it. I said that I wanted no rego no warranty etc, just the car for $500! No go. So it still sits there!

Thanks again

Luke

PS - David, I have heard a rumour that I should fit an NG box to a later model R25, instead of the UN1? Why would this be? I believe that the UN1 is a far superior bax after doing a bit of research.
 
I dunno, at the end of the day there's not much difference really, they all bolt in the same, they all work the same and unless your using it in really adverse conditions one just as reliable as the other. A manual 25 is a bloody nice car regardless of what box your using.
From memory a Valeo clutch kit is approximately $300, I know there are cheaper ones but Valeo is Valeo.

David.
 
What sort of gearing do R25 manuals run? (my Fuego was doing 3100 rpm at 100 kph, My friends R21 4sp auto is doing a leisurly 2600 rpm, and my R25 auto is revving its head off at around 3200 rpm) If the R25 manual is simarly geared to the auto, I would go for a Fuego gearbox as it is geared for smaller wheels, hence would make for relaxed highway revs in an R25. Plus it still has the casting on the bellhousing for a hydraulic clutch slave cylinder and are plentiful.
The tricky bit is finding suitable pedals and gear levers (perhaps Fuego pedals and R19 (right style of knob)levers could be made to fit). The next tricky bit would be the speedo pickup.
 
Yes, I have heard that the driveshafts need to be changed if a Fuego box is put it, and that you will not have a speedo as there is no sensor to suit the R25's instruments.

The gear ratios are;
1st - 3.36
2nd - 2.06
3rd - 1.38
4th - 0.96
5th - 0.763

That is for the UN1 type gearbox. I am not sure what the NG3 type's ratios are.

Regards

Luke
 
Hey LukeCass, did you ever hear from James_Perth who posted in May. He had his R25 converted to Fuego box, but we never got the juicy details on things like speedo and d.shaft length etc.
 
LukeCass, did you get all the bits for the conversion from a manual R25 - just wondering what you are doing re. pedals, gear lever, gearbox mounts etc.
Also, how intergrated is the auto trans computer into the engine management system - is it a matter of merely unplugging everything auto related? Are reversing lights activated by the computer, or off a conventional switch?
 
Luke,

If you like, I can give you the number of my mechanic on the Gold Coast who performed the conversion on my R25 some years ago. I was not the owner at the time so am not privy to the finer details. It might save you a lot of wasted time in 'discovering' for yourself what not to do.

Skip.
 
Hi All,

Yes, I got the complete kit from a car that had been rammed in the butt. That included the pedal box, gear stick etc. AS I said it has taken me about 8 years to find a conversion.

Aparantely you can just pull all the auto electronic wizardry off, and things run OK. Again I am not sure about the reversing light. I think it plugs into the back of the 'box. I will have to have a look.

I keep emailing James_Perth, but I still have not had a reply about the Fuego 'box conversion. I was really interested at the time, as I never thought I would find an R25 'box.

Also I would be interested in finding out more about the conversion from the mechanic in Qld.

Thanks again guys

Luke
 
Just to add some hopefully helpful info to this debate in what you have to do to make an auto r25 into a manual. The questions seem to be focussed on two areas, pedals and driveshafts. As an owner of a R25 and 3 Fuegos my observations are as follows :-
1) Pedals are common or very similar on both cars allowing for year to year model changes
2) Brake and Clutch Pedals mount on a rod that passes through a mounting on the steering column support structure. This is held in place by spring clips on each end.
3) Remove the clips and the pedals and rod can be removed. replace these with the parts from the manual car. You will then have to fit the relevant clutch parts (cable or hydraulic)for the conversion
4) Driveshafts - because the R25 is a lot wider than a Fuego these won't match if you were planning on swapping these over from a Fuego. Perhaps David Cavanagh could add to this in terms of what he did or what the length of his are. I suspect the Autos are narrower across the diff area than a manual but don't quote me. If any one has access to a parts book they may solve the problem

regards

Renoman
 
Many moons ago when I was semi interested in buying one of the seemingly plentiful and cheap 25 Auto's with a blown trans, I sat down with a parts book to see how easy the conversion was.

There were plenty of differences between the Auto and Manual models, principal being the computer, wiring loom and driveshafts. I decided it wasn't really my bag and all a bit more than I was interested in carrying out. However many conversions seem to have been carried out with nobody indicating the driveshafts are different or for that matter any other problems being incurred, apart from ripping the slush box out and slamming the cog box in. But I think I'll just stick to refurbing cars how the manufacturer intended them to be. It makes it easier for me :)

Simon
 
Hi

Yes, I would be grateful for an answer on the driveshafts. I too have heard that the driveshafts need to be changed and that the auto ones cannot be used. Then I have heard that this is not correct?

WHat is the case?? Please, any info would be great - I have many auto R25 driveshafts, but no manual driveshafts.

Hopefully David will have the answers. I am using a UN1 - R25 box, not a Fuego box.

Regards

Luke
 
In regard to R25 loom, computer as mentioned by Simon in earlier post, the Gearbox computer and associated loom are separate to the rest of the main loom and all unplugs when you remove the slushbox, so don't let that put you off during conversion. Having replaced an Auto with another auto, they seem to prefer the computer that they came with rather than mix and matching.

Re driveshafts etc has any one got a parts book etc to see if numbers are the same for manual and auto on 25's ?
 
renoman:
the Gearbox computer and associated loom are separate to the rest of the main loom and all unplugs when you remove the slushbox, so don't let that put you off during conversion.

Re driveshafts etc has any one got a parts book etc to see if numbers are the same for manual and auto on 25's ?
Click to expand...
It wasn't just the looms that put me off, it was how all the other looms had different numbers too, where the auto looms went into. As well as the numerous other differences between the cars.

The manual & auto driveshafts are actually different numbers, it has been checked. But as other people have done the conversion the problems would not seem insurmountable, especially if you have a trashed but complete manual car to work from.

Technically 25's aren't really my bag, they are too modern and too luxo. I just wanted to point out that from my personal "text book" research it may not be as simple as replacing one trans with another one. However the auto/manual driveshafts may be of the same dimensions but different specs, just like those of a 1289cc engined R12 and a 17TS. They fit either car, just one is stronger than the other. Someone who has actually done the conversion may be able to help with that info.

Simon
 
Thansks again guys,

Yes, a confirmation on these driveshafts would be great.
Unfortunately I did not/was not able to get the driveshafts from the manual car I took the gearbox from.

Are you there Dave? It seems you will be able to set the record straight.

Thanks again guys

Luke
 
What about fitting a 4 sp auto from a Subaru or an Audi? If changing gearboxes is so much hassle anyway, why not put in some thing a little cheaper and smoother than the reno auto!
Engine - gearbox adaptor plates are fairly easy to get made up, and this way one wouldnt have to screw about with pedals and gear levers.
 
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