Renault UN5 Trans

I got a mate,-- right ! Maybe an equal alternative to the becoming scarce G50 . Reportedly, used extensively in off road applications (dune buggies) where they endure some severe shock load treatments.
Just gotta do up a pattern for the various bell housings

Chris,
Do you know what its rated at by Renault?

Brett

Aah! nope, don't know much about them at all --But they look pretty tough and these are fitted with a 3.44:1 4 pinion diff and the gear shifter is nice and simple as well

What donor vehicle do they come from and how plentiful are they? What is the going price for one of them?

In the UK they were fitted to the Vans


Renault Master FWD 2.5 Diesel (R5) (UN5 Gearbox) 2499cc 235 3/89-98

Renault Master FWD 2.5 Turbo Diesel (R5) (UN5 Gearbox) 2499cc 235 3/89-98
They have been used for quite some time by off roaders

Cheers

Hmmmm whats that adjuster nut or whatever it looks like just behind the output shaft on the lefthand side???

A piece of Aussie ingenuity, that -- found to be particularly useful in the off road applications where a bit of crown wheel flexing seemed to be apparent after an airbourne manoeuvre in rough terrain. ( simply a bronze bump stop )Probably not needed for a GT40

The 3.44 ring and pinion sounds good. Does anyone know what the other gear ratios are? Also, are these available in the U.S.?

sorry to dig up an old thread but just found the ratios for this box

The Standard Gear Ratio's are:

• 1 st 4.45
• 2nd 2.43
• 3rd 1.48
• 4 th 1.03
• 5th .820 or .868

Ring and Pinion ratio is 5.85



and the box is 710 mm long

With a 26.5-inch tire height, and those gears, .82 5th, and a R&P of 5.85, you will have a top speed of 115 MPH @ 7000rpms

Guess that took a while to calculate.

Here are all the R-21 ratios. The R21 turbo is the one you want to start as a base for modification. If you do the 1 piece input shaft you can change the 1st gear to a more suitable ratio. Off the top of my head, it was about 2.6. While you are at it install a Qauife type TBD. Both my gearboxes have Quaife Torque biasing differentials in them. HUGE improvement!


UN1 gear ratios:
............ .21 Turbo ... Esprit GT3 ... Esprit SE, S4, S4s, V8
........... .UN1-013 ... UN1-028 .. ... UN1-016 026 & 027
1st ...... 3.364 .......... 3.364 ........... 3.364
2nd ..... 2.059 .......... 2.059 ........... 2.059
3rd ...... 1.381....... .... 1.41 ?? ........ 1.381
4th ...... 1.03 ............. 1.037 .......... 1.037
5th ...... 0.8205 ......... 0.76 ............ . 0.8205 ... (V8 = 0.76)
Final ... 3.44 ............ . 4.11 ............ . 3.89

1st, 2nd & 4th gear ratios are the same between the GT3 and Renault 21 Turbo versions, but 3rd, 5th & the final drive ratios are different. The final drive is very different, and that would make a huge difference in all the overall ratios (individual ratio X final drive ratio = overall ratio)

1st Gear ......... Overall
3.364 x 3.44 = 11.5722 21 Turbo
3.364 x 3.89 = 13.0860 Esprit SE, S4, S4s, V8
3.364 x 4.11 = 13.8260 GT3


3th Gear ......... Overall
1.381 x 3.44 = 4.7506 21 Turbo
1.381 x 3.89 = 5.3721 Esprit SE, S4, S4s, V8
1.41 x 4.11 = 5.7951 GT3

5th Gear ........... Overall
0.8205 x 3.44 = 2.8225 21 Turbo
0.7600 x 4.11 = 3.1236 GT3
0.8205 x 3.89 = 3.1917 Esprit SE, S4, S4s, V8


I copied the above data from an old thread. You can find just about everything known about Renault Transaxles If you search "Renault UN1 transaxle, everything"

Howard- I believe it was just humor, in reference to the date of the post to which you replied- Oct 9, 2006.

Hummm.........No Chris, and you too Brian. I get it now! But I do wonder how long that guy's engine lasted...............I'm just getting old I guess. Merry Christmas ya all.