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nyk
18-11-2006, 01:15
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
18-11-2006, 11:19
I think its the circlips in the JB3's?

The Willy box's are a bit stronger though

wavy
18-11-2006, 15:39
I think its the circlips in the JB3's?

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

nyk
18-11-2006, 15:55
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
18-11-2006, 19:03
cant really strenghten the gearbox without stripping it down. then you can shot peen and polish the gear sets

nyk
18-11-2006, 21:55
it will be stripped down, thats why I'm asking which are the common parts that fail so I can replace it. :wink:

cliorod
18-11-2006, 22:49
Nyk,
At the risk of getting flamed :oops: , :( I have "Rallied" Renaults in various guises from about 1990,starting with a 5GT pushing out 200bhp :twisted: :roll: :twisted: ~~ 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 :oops: :oops: .We soon solved that :wink: :wink: ,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 :oops: :oops:
I will get all the details,and see if my mate has got some pics of the circlip mods
hope this helps
Rod

richy
18-11-2006, 23:07
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! :wink: 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
18-11-2006, 23:17
Cheers for that Richy,was expecting a torrent of abuse :( :roll: :(
I can get good prices on exchange genuine Renault boxes :wink: :wink:if anyone is interested ask Clio Pete :roll: :roll: ~ He has just got a JC5.
please feel free to PM me for details

richy
18-11-2006, 23:46
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!

nyk
19-11-2006, 00:06
cheers rod, thats really good advice.

The box I have is on about 40K, but you never know how they have been driven and always intended to get it rebuilt as dont really wanna be pullin it out again next year when it goes!!

Never actually had a gearbox go on me, but I know its a really common thing and just wanted to take every precaution I could on the track car as it will get some hammering.

I've got someone who is excellent to rebuild the box for me.

cliorod
19-11-2006, 00:38
Hi Nyk ~~ glad to be of help.
Although you have a mate who is going to sort your gearbox out.
for future reference and for other members who require gearbox rebulids.
The guy I have been using is happy to to knock a bit off for members. :wink:

He charged me £150 for a strip and rebuild on a JB3,and will do the same for others :lol: :lol:
Obviously any parts etc etc are extra,but he knows his stuff,can supply most of the LSD's available as well as gearkits on any gearboxes.
Could be worth your while giving him a bell to see what he recommends
His name is Keith,and contact details are below.www.kntransmissions.com
Rod.

cliopete
19-11-2006, 01:17
As Rod said I got a good deal on a genuine fully reconditioned Renault JC5 Williams gearbox from Kitchens in Burnley. I think all the internals are new on these boxes, only the old casings are reused.
The JC5 box has slightly wider/stronger gears, taper roller bearings instead of plain roller bearings but the best bit is that they did away with the circlip method of retaining the diff. I'm not sure if this method was brought in as a running change or is the same on all JC5 boxes, but the diff is now retained by a metal plate bolted to the crown wheel....... so no popping circlips. You also get a full 12 month guarantee. Peace of mind :lol: :lol: Should be good for another 100,000 miles if the rest of the car lasts that long. :twisted: