Diff Centres And Final Gears

[salad]

hey guys/girls

ive got an R32 gts-t with a different final gear but stock viscous diff. from my calculations, it is ~4.766.

my friend has an R32 also, and has a cucso 2 way diff but stock final gear.

she wants to swap her diff with me cos she doesnt need it and i do.

my question is, is it hard to swap the diff centres but keep the final gears as they are? as i really want to keep my shorter final gear.

is there anything like preload or anything else like that that needs to be done, as a mate of mine mentioned this, but i always thought that diff centres were pretty much interchangable pretty easily.

and the final gear is just attached to the diff centre isnt it?

cheers, showza

[FATGTS-R]

I apoligise to go slightly off topic but can you tell me what rpm you sit at when doing 100km/h with the shorter gearing?

[salad]

in 5th i sit at ~3050rpm

in 4th i sit at ~4000rpm

stock gearing suggests i should sit at ~2750rpm in 5th and ~3600rpm in 4th

i have checked my numbers thouroughly and can only bring it down to a ~4.766 final gear

Edited January 17, 2006 by salad

[Cubes]

Is that going by the tacho?

Going by the tacho my stock diff gering has it sitting on 2980rpm or there abouts, basically 3000rpm at 100km/h.

On the PFC H/C its ~2800rpm. I'll grab the exact figures today as I forget.

[TokyoTaxi]

It's not a big deal to swap diff center's but should be done by someone who knows what they're doing. There are things that need to be done like setting up the heel & toe & backlash etc and that requires a magnetic base dial inicator and bearing blue etc etc so best left to the professionals. Swapping the center will not change the final drive ratios since they are controlled by the crownwheel & pinion gear which you are not changing.

[salad]

yeah, thats good.

the crown gear is held onto the diff centre though isnt it?

and how is it held on there? is it hard to take the crown gear off?

and i checked the speed and rpm with the taco and a GPS and my speedo was spot on

[salad]

anyone else know much about diffs?

if this sorta stuff has already been posted up before, please point me in the right direction

cheers

[TokyoTaxi]

Taking the diff center out and re-installing it into the crownwheel is not an easy thing to do properly without tooling to hold everything in place. I did a diff center replacement at home once and I would not recommend it as a DIY unless you have no other options.

If you MUST do it yourself, just be carefull to keep the backlash shims in their removed order / postion and re-install them as they came out. You'll also need 2 pretty strong people for this job, one to hold the crownwheel and the other to do the breaker bar / socket / torque wrench duties Oh and keep everything clean while doing the job. Would be a shame to do all that work and have a bearing failure

[TokyoTaxi]

Oh and to answer the other question, the cover has like 8, 12 or 14mm bolts, then the crownwheel and diff center cradle is held in place with 4 19mm bolts, then the center is bolted to the crownwheel with a bunch of 17mm bolts. I may be a bit off on the head sizes since it's been a while.

[salad]

ah k, awesome, cheers fat32.

might just take the 2 diffs out and give it to someone to do...