34 replies to this topic

[Ian91]

Thanks jack

[bazeng]

Just buy mine.... 150 shipped! No cvs

[25gtv]

Bazeng, is that $150 shipped for the same centre diff spool thats in the ebay ad? Im keen

[Ian91]

He said its not but it's been made by a gearbox guru, but it's gone I just put money in his bank

[25gtv]

Ah dam, Oh well Im still winning it on ebay!

[Ian91]

Ah dam, Oh well Im still winning it on ebay!

Did you end up winning it? Or someone else get in at the end?

[25gtv]

Na someone else got it...

Edited by 25gtv, 09 August 2012 - 01:18 PM.

[Ian91]

Ive got one of those spools (viscous coupling eliminator) at home just in case I ever need to use a 2wd dyno lol. But yeah, never used it.
However I thought mine was a PPG billet item? (see pics)  Solid piece of gear and weighs a tonne.

As Tim mentioned, for a quick switch to rwd without anything other than opening the end case on the gearbox, then u can use the spool but you risk smashing the centre diff and risk damaging other gearbox internals in the process.

But if you want to do rwd the proper way and have a much safer and stronger box, youre better off opening the box up and swapping the centre diff out for a welded one. Then your only worries are smashing the transfer case or rear axles. Their still easier and cheaper to replace than a gearbox!! Lol

that is what the one I bought off baz looks like, is a centre diff hard to get a hold of? and is it hard to replace?cheers

[Evo-00x]

Well you wouldnt weld a good, functional and internally structurally sound AWD centre diff if you can help it from a normal working gearbox.
Lots of guys blow centre diffs and even though internally they are ratshit with scrapes and gouges taken out of the housing from failure, as long as the outer housing drive gear teeth and the lower pinion at the bottom of the housing is in one piece then thats what's important for a welded centre diff. ie you dont need the guts of the centre to be good, you dont need the cross-shaft and you dont need the spider gears. Problem is, moost of the time the lower pinion also shatters in a blown centre diff so its the luck of the draw.

Your perfectly good working centre diff can be used for normal AWD purposes if you ever want to go back to an open AWD (not welded/locked) centre in future. Or it can be sold off if you dont need it and intend to stay FWD/RWD/constant 4WD.

To get to the centre diff you need to remove the gearbox rear cover, the VCU, the end nuts on the shafts, 5th/reverse etc then the sandwich plate of the casing to expose and pull the centre diff out.

At one stage here I had 4 broken centre diffs and only 3 were welded up and made their way into FWD or RWD conversions. A guy went to weld his own up but he welded the lower pinion on a tad bit of an angle and not sitting flush in the base of the housing. Therefore the centre diff sat on a bees doodle of an angle and was a tight squeeze when lowered onto the output shaft in the casing. I helped the guy out by getting Frankie to weld my last spare damaged centre diff and gave it to the guy at no cost. Ive still got his old one here that Im thinking whether or not I can remove some of the welds and knock it flat to reseat the lower pinion properly.... it was only about a mm off being dead flat and useable. (see attached pic)

Rule #1 for welding centre diffs yourself is to make sure the pinion is dead flat. After the first tack weld it will lift the opposite side up, something that the guy didnt realise, so you need to knock it back down and ensure a dead flat fit before continuing to weld a second and third spot weld, then test it in the gearbox to make sure it slides onto the output shaft easily. After that its a case of knowing when to walk away and let it cool down, then come back and weld some more, walk away, then come back etc. You dont want to be welding/heating the housing up for a prolonged period of time, so know to walk way, let it cool and get back to it. Let it cool down by itself at room temp. Oh, and dont let splatter get into the inside of the lower pinion where the output shaft slides into. I usually use a big washet and nut and bolt to hold the pinion flat and protect the inner diameter of the lower pinion from splatter

Attached Thumbnails

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[jack be nimble]

pretty easy thing to make from a worn out visc.......I think I did the last one I made in half and hour...was ugly but worked.

Is that the one I have now? Lol

[Ian91]

Well you wouldnt weld a good, functional and internally structurally sound AWD centre diff if you can help it from a normal working gearbox.
Lots of guys blow centre diffs and even though internally they are ratshit with scrapes and gouges taken out of the housing from failure, as long as the outer housing drive gear teeth and the lower pinion at the bottom of the housing is in one piece then thats what's important for a welded centre diff. ie you dont need the guts of the centre to be good, you dont need the cross-shaft and you dont need the spider gears. Problem is, moost of the time the lower pinion also shatters in a blown centre diff so its the luck of the draw.

Your perfectly good working centre diff can be used for normal AWD purposes if you ever want to go back to an open AWD (not welded/locked) centre in future. Or it can be sold off if you dont need it and intend to stay FWD/RWD/constant 4WD.

To get to the centre diff you need to remove the gearbox rear cover, the VCU, the end nuts on the shafts, 5th/reverse etc then the sandwich plate of the casing to expose and pull the centre diff out.

At one stage here I had 4 broken centre diffs and only 3 were welded up and made their way into FWD or RWD conversions. A guy went to weld his own up but he welded the lower pinion on a tad bit of an angle and not sitting flush in the base of the housing. Therefore the centre diff sat on a bees doodle of an angle and was a tight squeeze when lowered onto the output shaft in the casing. I helped the guy out by getting Frankie to weld my last spare damaged centre diff and gave it to the guy at no cost. Ive still got his old one here that Im thinking whether or not I can remove some of the welds and knock it flat to reseat the lower pinion properly.... it was only about a mm off being dead flat and useable. (see attached pic)

Rule #1 for welding centre diffs yourself is to make sure the pinion is dead flat. After the first tack weld it will lift the opposite side up, something that the guy didnt realise, so you need to knock it back down and ensure a dead flat fit before continuing to weld a second and third spot weld, then test it in the gearbox to make sure it slides onto the output shaft easily. After that its a case of knowing when to walk away and let it cool down, then come back and weld some more, walk away, then come back etc. You dont want to be welding/heating the housing up for a prolonged period of time, so know to walk way, let it cool and get back to it. Let it cool down by itself at room temp. Oh, and dont let splatter get into the inside of the lower pinion where the output shaft slides into. I usually use a big washet and nut and bolt to hold the pinion flat and protect the inner diameter of the lower pinion from splatter

. thanks for the write up mate, I probly wouldn't do it myself as I don't have a welder or a spare centre diff, if you did fix the wonky one would you sell it? or can you get me one? you seem to be the guy to see about gearbox stuff from what I've read

[Evo-00x]

Not only me... there's other knowledgable blokes on here too but they are probably smart enough not to talk as much about gearboxes lol
If I do end up fixing it, (but chances are its non reversible) I think I will probably keep it though as Im all out of centre diffs unfortunately... plus my brother needs a centre diff anyway to convert to 4-spider or weld up yet lol

[BMGTZ]

Is that the one I have now? Lol

were did you get it?

Ive made a lot....for various people.

[Cranked]

I blew my centre diff, 2nd launch on the strip after dropping tyre pressures. Loaded the car onto the trailer, took it home, stripped the box welded the centre diff and went back the next week to run a PB. I also feel as though my duck in on corners became alot tighter. Alternatively vcu eliminators are quite simple to make with a drop saw, grinder and welder.

Edited by Cranked, 16 September 2012 - 09:53 AM.

[bazeng]

Anybody here still do the 4 spider conversion?

I may need one....... For a friend...