Best place for gearbox rebuild kit - plus taller 5th?

[Robbie Corbett]

Hi All,

My gearbox crunches going into 3rd, given how common this is i'm assuming 3rd gear syncro has failed or is on its way out. Fresh oil seemed to make no difference at all. All other gears are perfect, no horrid noises etc.

I am more than happy to give this a crack, I've rebuild several boxes in the past so feel fairly confident that I can get it apart and back together (famous last words). I also see that I can buy the bearing/syncro kit from Renault however people seem to say there are normally missing/wrong parts in the kit. I can also buy it from Pure at quite a premium over Renault however they claim that the kit is complete and checked.

What do people usually do here?

#2 - can I get 5th gear off without the official puller?

#3 - are there any options for a taller/longer 5th to drop cruising RPM?

Thanks very much!
Rob,

 

[Tim.]

@NorthloopCup is our resident gearbox professor.

 

[NorthloopCup]

You can get the gear off, but I’d imagine you’ll chip the teeth on 5th. Got one in currently that’s had the same treatment!!

Definitely options for changing 5th gear, but I’d need to look at ratios.

 

[Robbie Corbett]

@NorthloopCup is our resident gearbox professor.

Thanks mate, NorthloopCup comes up in nearly every gearbox post

 

[Robbie Corbett]

You can get the gear off, but I’d imagine you’ll chip the teeth on 5th. Got one in currently that’s had the same treatment!!

Definitely options for changing 5th gear, but I’d need to look at ratios.

Cheers mate, I'll check the 'old and never used' tool draw as I've got quite a few pullers in there, hopefully can find something which doesn't chip the teeth. The IB5 and BC boxes in old fords have a very similar 5th gear arrangement and I've had quite a few of those apart.

Just read a bit of blurb which suggests the cruise control will no longer work with altered 5th ratios

Any hints on a rebuild kit? And in your experience is it common to find damaged teeth on cars with a weak syncro?

Cheers
Rob,

 

[Robbie Corbett]

Hmm, just watched a video of a JC5 coming apart and the 5th gear arrangement does not look so much like the ford IB5 as I thought....

 

[Robbie Corbett]

Smaller of the two (the gear without the syncro ring) looks ok, pretty sure I can modify a puller to remove this without damaging the gear however the larger gear (which uses BVI 1170) looks like it will be a pain without the proper tool hmmmm.

@NorthloopCup would you be willing to either tell me where you buy your rebuild kit parts or sell me a rebuild kit?

 

[NorthloopCup]

Smaller of the two (the gear without the syncro ring) looks ok, pretty sure I can modify a puller to remove this without damaging the gear however the larger gear (which uses BVI 1170) looks like it will be a pain without the proper tool hmmmm.

@NorthloopCup would you be willing to either tell me where you buy your rebuild kit parts or sell me a rebuild kit?

The smaller gear is the one that needs the low profile pulled on it mate, and is the one that you can chip the teeth off. Lol! It’s quite tight on the shaft. The other gear with the synchro ring on is the easier of the 2, so looks can be deceiving.

Regards the wear on teeth etc, if it’s crunching, the dog teeth on the gear and selector hub will be rounded over, so you could try a new synchro, but I doubt it’ll last long. Selector hub is around £120, gear is about £65 and synchro ring is £30.

I get everything from Renault Wolverhampton, so you’re better off stripping your box and inspecting it to see what it requires.

 

[bloke]

pick a gear, any gear, look at it, don't let me see it and put it back in the box.....http://www.volvohowto.com/jc5-jb3-jb5-jb1-and-jb0-renault-gearbox-ratios-and-applications/

 

[Robbie Corbett]

The smaller gear is the one that needs the low profile pulled on it mate, and is the one that you can chip the teeth off. Lol! It’s quite tight on the shaft. The other gear with the synchro ring on is the easier of the 2, so looks can be deceiving.

Regards the wear on teeth etc, if it’s crunching, the dog teeth on the gear and selector hub will be rounded over, so you could try a new synchro, but I doubt it’ll last long. Selector hub is around £120, gear is about £65 and synchro ring is £30.

I get everything from Renault Wolverhampton, so you’re better off stripping your box and inspecting it to see what it requires.

Ahhh! Thanks ever so much mate. I know that you refurbish lots of these boxes, its nice that someone who makes money from this is also willing to give help to non customers. Much appreciated!

Rob,

 

[Robbie Corbett]

pick a gear, any gear, look at it, don't let me see it and put it back in the box.....http://www.volvohowto.com/jc5-jb3-jb5-jb1-and-jb0-renault-gearbox-ratios-and-applications/

Awesome link!

 

[bloke]

Just double check any ratios, not sure on that list but sure I found a couple of pdfs that have the wrong ratios on. Think they were on 5th and 6th so hopefully not any on that list but when you do a speed calculator the wrong ones are easy to spot!!

 

[DaveL485]

Just read a bit of blurb which suggests the cruise control will no longer work with altered 5th ratios

It won't. The system freaks out at any miscalibrations detected, it turns all the ABS and ESP off if you run different tyre profiles front/back for example.