fuel Posted January 9, 2009 Share Posted January 9, 2009 Hey guys, just in a bit of a pickle with my diffs. My original diff is 3.545 ratio non-LSD, while the diff I put in a year ago is 3.909 ratio with LSD. I'm pretty happy with the LSD but I can't help but feel the 3.909 is making the engine rev too high at 100km/h (which is actually about 120km/h indicated on the speedo), so I'm wanting to basically make a 3.545 LSD diff. Now I'm not too up to the play regarding diffs, especially with things like backlash, preload etc to consider. I just pulled the diff nugget from the 3.545 diff out from the casing, and I thought probably the easier way would be to use the original 3.545 casing (and pinion gear) with the 3.545 crown wheel and the LSD centre from the 3.909 diff. However I realised the diff centres have the bearings attached on them (along with their accompanying shims), I know the bearings can be pulled off - but would it be absolutely vital to use the original bearings and shims from the 3.545 diff centre on the 3.545 diff housing? Or could I get away with leaving the bearings on the 3.909 LSD centre and use the shims from the 3.545 diff? I don't exactly have the tools to measure pre-load, backlash etc so really don't want to mess something up that I shouldn't be. Cheers Quote Link to comment Share on other sites More sharing options...
Ke36 Posted January 9, 2009 Share Posted January 9, 2009 your guna have to pull them apart completely to do the swap will envolve redoing the backlash and preload same reaosn my hilux diff is still 4.3 and no 3.9,(an u think 3.9 is bad ) Quote Link to comment Share on other sites More sharing options...
Jase Posted January 9, 2009 Share Posted January 9, 2009 are they the same nugget between 3.5 and 3.9 ie same widths and bearings? or did you swap the whole housing? if you're using the o.g housing with a new nugget best bet is to take it apart and make sure your crown wheel and pinion are going to bolt to the lsd center then take it to a pro to be shimmed and adjusted as i wouldn't think lsd's are too easy to find for your stz and blowing one coz a mate of a mate said he had done a few before would suck Quote Link to comment Share on other sites More sharing options...
fuel Posted January 9, 2009 Author Share Posted January 9, 2009 your guna have to pull them apart completely to do the swapwill envolve redoing the backlash and preload same reaosn my hilux diff is still 4.3 and no 3.9,(an u think 3.9 is bad ) How come I'll have to pull both diffs completely apart to do the swap? I want to use the original diff housing (remember this is for an IRS diff) so I don't have to mess about with taking the pinion gear out, so effectively I'll be using the original 3.545 pinion in the original diff housing with the original 3.545 crownwheel, but using the LSD centre from the donor 3.909 diff, which has the bearings attached to the centre, and with the side shims from the 3.545 diff. Make sense? Quote Link to comment Share on other sites More sharing options...
fuel Posted January 9, 2009 Author Share Posted January 9, 2009 are they the same nugget between 3.5 and 3.9 ie same widths and bearings?or did you swap the whole housing? if you're using the o.g housing with a new nugget best bet is to take it apart and make sure your crown wheel and pinion are going to bolt to the lsd center then take it to a pro to be shimmed and adjusted as i wouldn't think lsd's are too easy to find for your stz and blowing one coz a mate of a mate said he had done a few before would suck Yeah everything is the same between the diffs apart from the different crownwheel and pinions for each ratio. Yeah might get my LSD looked at while it's out too, you're right starion LSDs aren't easy to find and are usually expensive and are only the clutch pack type so wear out over time. Quote Link to comment Share on other sites More sharing options...
HUNTD Posted January 9, 2009 Share Posted January 9, 2009 what i done when i changed my open diff to my trd one on my chaser was this pulled the bearings off using a modded gear puller ( had to due to were the bearings sat ) when i pulled the shims out i made sure they went back in on the correct side changed centers over ( easy also used new crown wheel bolts ex toyota ) when it came to re-assembly of everything i sat the diff in the craddle, making sure it was meshhing correctly, placed the shims/washers in on there correct side's. torqued the bolts up on the caps then got engineers blue and chucked it on three of the crown wheel teeth rotated the crown wheel in till the ink came back around and used that to check for meshing probs as the crownn wheel turns and meshs with the pinon it whips the ink off on the surfaces that touch each other and you can tell weather or not you have good teeth contact most bearings now days you can get about 100k kms out of ( un opened of coarse ), but if i were you man i would change them, regardless if there notchy or not, just for peace of mind tell me what the bearing numbers are and i can get them at cost + 10% Quote Link to comment Share on other sites More sharing options...
HUNTD Posted January 9, 2009 Share Posted January 9, 2009 rgds jarred lol Quote Link to comment Share on other sites More sharing options...
HUNTD Posted January 9, 2009 Share Posted January 9, 2009 oh yea if you want pre load dailed in correctly we can do that at my work providing you have shims etc jarred Quote Link to comment Share on other sites More sharing options...
Hemi Posted January 9, 2009 Share Posted January 9, 2009 if your pulling the lot out aka removingthe nugget with crown wheel then reoveing crownwheel from siad nugget and bolting the crown onto the lsd carrier , i cant see why it would need to be preloaded again, if you have to take the bearings off to get the crownwheel off then yes you would be wise to take the lot into someone with tools and get it done there . i know from personal experiance that diffs that are loaded properly tend to take the hardening off everything and self destruct :S Quote Link to comment Share on other sites More sharing options...
fuel Posted January 9, 2009 Author Share Posted January 9, 2009 sweet well that's a bit re-assuring. I don't need to remove the bearings to get the lsd centre out, so was hoping to just keep the bearings on the lsd centre from the 3.909 diff and use them in the 3.545 housing. jarred I read about that machine blue ink in the conquest/starion workshop manual so will give that a go to see if it's all meshing sweet. bearing number is 18731. chur Quote Link to comment Share on other sites More sharing options...
FLAWLES Posted January 10, 2009 Share Posted January 10, 2009 you sure thats the bearing number? should be a number on the inner race and outer shell? that engineers ink is a good trick to remember Quote Link to comment Share on other sites More sharing options...
fuel Posted January 10, 2009 Author Share Posted January 10, 2009 Sorry I think it's 17831, NSK bearing. Quote Link to comment Share on other sites More sharing options...
forced Posted January 11, 2009 Share Posted January 11, 2009 I'd have thought you'd be better off to just get hold of a 3.545 LSD from a VR4 or a GTO and make it fit. The basic construction shouldn't be too much different. Steve Quote Link to comment Share on other sites More sharing options...
fuel Posted January 11, 2009 Author Share Posted January 11, 2009 Are you meaning the whole diff, or the diff centre by itself? I very much doubt a complete VR-4/GTO diff will fit, they are completely different. Quote Link to comment Share on other sites More sharing options...
Ke36 Posted January 11, 2009 Share Posted January 11, 2009 hmmmmmmmmmmm irs diff forgot about that in that case i have no idea, never had a play with one maybe have an ask on projectzerog? theyl porbly set u right and maybe even know some larger upgrades etc Quote Link to comment Share on other sites More sharing options...
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