Gearbox issues??

[nyk]

I asked this question last week but dont know if anyone read it or not cos it was at the end of a waffle on carbs.

Does anyone know which actual component is the faulty bit that causes the gearboxes to fail so much??

I was told it was a bearing that makes the shaft loose an thus makes the gears tear each other apart. But not sure how accurate it is.

With these gearboxes failing sooo much it must be a common component that is just not strong enough.

Anyone know or ideas???

[Andy P]

I think its the circlips in the JB3's?

The Willy box's are a bit stronger though

[wavy]

I think its the circlips in the JB3's?

yep apparently they pop off and are never as strong once fixed

[nyk]

I've got a willy box for the track car, but wanna strengthen it best I can so no chance of it fallin to bits.

[MAXIBOY]

cant really strenghten the gearbox without stripping it down. then you can shot peen and polish the gear sets

[nyk]

it will be stripped down, thats why I'm asking which are the common parts that fail so I can replace it.

[cliorod]

Nyk,
At the risk of getting flamed , :( I have "Rallied" Renaults in various guises from about 1990,starting with a 5GT pushing out 200bhp ~~ Flywheel power,right upto my current Clio,All have had either a JB3/5 boxes in them ~~ albeit latterly I have fitted an LSD.but I have only ever had problems once ~~ in probably over 70/80 Rallies.In my experience over these years,Start of with a good /refurb unit,ensure the gearbox mountings are in a good condition,and now the slightly contentious bit :o .FULL revs and dropping the clutch ????,ok if you have the Grp"A" mounts or Gunners R19 conversion,where ther is not movement in the engine/gearbox. I always used to get the car rolling,and then floor it ~~ like I say,that is how I have driven ~~ On a dragstrip,I understand the need for instant power/grip ~~ On a rally you have 3/4 miles to make up the odd tenth/second you loose at the start.
The only problem,I had on a rally,was when the dropped the near side wheel into a ditch,under power and that B**tard circlip popped out .We soon solved that ,we put three dowels/screws in to hold it in place.I am told by the ex-racers this was a common problem,with drivers "riding" the "rumble strips" on circuits,the wheel would lift off,and when it "dropped" back onto the track,the backlash/play through the diff would pop the circlip ~~ instant no drive
I will get all the details,and see if my mate has got some pics of the circlip mods
hope this helps
Rod

[richy]

as rod says get a good rebuilt or new box first, and having the '4th' mount is a great help, fitted mine after a mount snapped and messed up the diff/shaft couple of year ago! lol

i got a box from reno the other year and only done 6k on it, first thing i did was trackday it lol not had any problems with the box itself! JC5 btw

[cliorod]

Cheers for that Richy,was expecting a torrent of abuse :( :(
I can get good prices on exchange genuine Renault boxes if anyone is interested ask Clio Pete ~ He has just got a JC5.
please feel free to PM me for details

[richy]

yeah i got mine through work at a good rate!

also fitted the '4th' mount at the same time, i always try to get mine rolling first before flooring it after destroying the original box!