What Renault gearbox

Hi all

I hope you can help me. I am trying to locate a Renault UN1 gearbox to mate to a sub 200bhp Rover v8. All of my local scrap yards don’t have any 21 turbos or R25 turbos but several do have the Renault 21 2.2 injection cars. Is the only reason the UN1 is specified is its increased power handling ability or are its physical dimensions different to those gearboxes used in the stand Renault 21?

Is there a way of telling what Renault has what gearbox other than grubbing around scrap heaps?

I have found getting hold of a UN1 is extremely difficult so any information offered on how to get round this problem would be gratefully received.

The R21T transaxle is now becoming increasingly hard to find. You may also need a Renault 30 bellhousing which are unfortunatley equally as rare.

Alternatively Renault 25 transaxles are perhaps more easily available. The only major difference is the final drive ratio, being somewhat lower in the 25 that the 21T.

In your case, with a 200bhp engine, you may struggle to pull the tall gearing of the 21T box. All UN1 boxes have the same power handling ability.

My GTD has a 302 & runs the lower geared box, which is fine up to about 140mph.

As brett points oput, Chris Cole may be able to help with either box. His number is 01952 222 155.
Thanks for that guys i will give him a call.
I have had absolutely no joy finding a box locally so last night i thought i would have a look on some French websites to see if it was possible to "achter un UN1 boite de vitesse" or buy a gearbox (i think) but without any luck. Now if i only new the French for scrap yard I’m sure i could find bucket loads of boxes..... Perhaps

Has anyone tried this route?
Jules be careful. I bought my car last year and am now on my 3rd renault box rebuild in 5000 miles - not fun. now i might just be unlucky but each time the shaft has snapped. you will find there is a welding mod that is meant to strengthen the box - but my last box had that done and still failed. likewise if the box is not centered dead on thru the adaptor plate you are in trouble. Topically a number of us are going with a special kit via derek bell whom is having the stuff made at quaiffe. use the search engine to find out more - or e- mail and i will send you details. the kit has been used in his lola - mated to a chevy with plus 300hp if i recall correctly.sounds like the long term fix.
Sorry just though - 1. You can buy one of my broken boxes and repair it!! Or better German/Swedish in Apsley Herts bizarrely sell Renault boxes ex stock for around 425 + vat guaranteed for 6 months - if you don't tell them what it is going in - unfortunately I did!!i think it's on an exchange basis so you might want to pay something stupid for one of my old ones after all. i am in kings langley herts.
Hi Keith + all -
The conversion Keith mentions is currently being used in Derek's GTD Lola T70, Roy Smart's GTD40 Mk1, Dave Parker's GTD R42 and Malcolm MacAdam's GTD40 Mk1.

Derek's Lola has a powerfull dry-sumped 350 Chevy which if I recall must be 450 to 500+BHP as its flippin fast!

Dave's R42 - Smart-Tech injected 350 Chevy currently puts out about 480BHP (550+ soon!)
Roy's Mk1 - Smart-Tech injected alloy 347 stroker - estimates range 450-550BHP

Even with these engines and after 2yrs+ of sprints, Hill-Climbs, Track days using Slicks and being double-driven - Derek's Quaife conversion has stood the pace.

Even when Dave's std diff exploded (now has Quaife ATB also) - the shaft remained good although the gearbox casing exploded. Once parts were fitted to new casings and ATB - all was well again!

Cannot praise this conversion enough really.

Enjoy yours when you get it Keith - you'll not be dissapointed.
There you go Jules! from a man that knows! Thanks Paul for the reassurance. After all the financial pain endured, it will be great to get a permanent fix

Howard Jones

Keith Are the boxes you broke R21 Turbo's or a different one? How much power do you have? Engine? Are you using slicks for tires? Drag raceing? How did they break? Your experience seams to be on the bad end of the known bell curve for the strenght of these gearboxes. Do you think that you sorce has been a bad one? Have all they been rebuilt?

Robert Logan

Defunct Manufactuer - Old RF Company
The Audi gearboxes are much easier to find, stronger (in standard form) and similar in size, so little modification to chassis if any.

Ken Saunders has one fitted to his car and as we all know is ALWAYS ready to help anyone who asks. I am sure he would be happy to hear from those with trouble finding an UNI box also as he now lives in France.

Good luck,

Howard, yes they have all been R21. I'm only putting out around 300HP. The car has only been run on the road. Each failure has come following a few repeated 'full on' blasts thru the gears. The worst when I had just seen off a new ferrari to the plaesure of my passenger - only for us to breakdown and be stranded for three hours!! not cool!

Howard Jones

I guess I'm have to take it easy with the gear changes. I am going to do the complete quafe internals and LSD at some point in the future. I am about 90-95% complete now and am hoping to go to the body/paint shop this Fall/winter. I want to drive it a little to sort out most of the bugs before I take it all apart to paint. Let us know how the quafe upgrade goes.
So KeithK tell me exactly what broke in your boxes?? I have 6 R21T boxes a couple of 30 4 and 5 speeds here in the workshop. Havent broken mine yet, but would be interested to know.