xwagon 168 Posted June 14, 2019 Hello people, what diff ratio should a xd fairmont ghia v8 be? Is drum braked. Guy is going to look at tag but would like to know from you guys too. Thanks Share this post Link to post Share on other sites
gerg 10,871 Posted June 14, 2019 Should be 2.78 from memory, could also depend on if it's a 4.9 or 5.8. Edit: 4.9 got the 2.92 either manual or auto, 5.8 manual was 2.92, auto was 2.77 and some highway patrol cars got a very rare 2.53. Sent from my CPH1903 using Tapatalk Share this post Link to post Share on other sites
xwagon 168 Posted June 14, 2019 Thanks and its the 2.77 that wont fit the other housings? Looking to use the lsd in my valiant. Share this post Link to post Share on other sites
gerg 10,871 Posted June 14, 2019 The housing itself will tell you what series it is, unless it's a weirdo hybrid one (ie 75 series gears in 78 housing) Should be 0575 series with those ratios. You will find that on your tag, stamped on the centre somewhere and also on the gears themselves.Like this:Sent from my CPH1903 using Tapatalk Share this post Link to post Share on other sites
xwagon 168 Posted June 15, 2019 Thanks, will just have to wait till he tells me the ratio, only want the lsd for my ve val diff, if its the 75 series i cant use it i my 78 housing? Thats what someone told me? Share this post Link to post Share on other sites
gerg 10,871 Posted June 15, 2019 It's been too long so all that info isn't fresh in my head. It can be done, it's just the issue of pinion spacing in relation to the crown. There is a thick shim to do this that goes between the inner pinion bearing race and the back of the gear. I think it's something like 120 thou.I'll explain why: the difference between 75 and 78 housings is in the pinion depth, and is determined by how deep the step for the inner pinion bearing is machined. 75 has the pinion deeper into the crown, as the 75 crown wheel is smaller in diameter and the pinion needs to go deeper into mesh to meet it. Putting that shim in behind the pinion puts it into proper mesh with the crown and corrects the difference between housings.There is an instance where there is a different carrier used, on the 2.77 diffs they had a greater offset on the crown wheel to allow for larger diameter pinion gear. This centre is only compatible with those gears. In some rare instances, they've used that weirdo carrier with 2.92 gears and have a big shim under the crown wheel to space it back across to where it normally would be.All other centres should swap.But 25 spline centres won't work with 28 spline axles. The holes are too small for the axle diameter.Be sure to get the correct carrier bearings, as there are differences. Sent from my CPH1903 using Tapatalk Share this post Link to post Share on other sites
deankxf 20,288 Posted June 15, 2019 pretty sure it will be a 2.92 diff unless it's got a BW35 auto, might be a 2.77 then Share this post Link to post Share on other sites
351XD_Fairmont 604 Posted June 15, 2019 Weren't all v8's disk brake as standard in xd's or was that lsd? Share this post Link to post Share on other sites
gerg 10,871 Posted June 15, 2019 Weren't all v8's disk brake as standard in xd's or was that lsd?Disc brake and LSD as far as I know. I converted mine for this reason (was a mandatory option)Sent from my CPH1903 using Tapatalk 1 351XD_Fairmont reacted to this Share this post Link to post Share on other sites
xwagon 168 Posted June 19, 2019 So the guy has come back to me about this diff. Said is t is 2.9 ratio, so that must be the 2.92 one, said it is lsd, so my question is, will this centre work in my ve valiant. 25 spline is what i have. Share this post Link to post Share on other sites
deankxf 20,288 Posted June 19, 2019 32 minutes ago, xwagon said: So the guy has come back to me about this diff. Said is t is 2.9 ratio, so that must be the 2.92 one, said it is lsd, so my question is, will this centre work in my ve valiant. 25 spline is what i have. i would assume so if it's a 302. V8. i'd imagine it could be 28 spline possible for a 351. Share this post Link to post Share on other sites
xwagon 168 Posted June 19, 2019 My understanding was that 28 spline did not start till after the xf? And that all bw diffs before that were 25 spline. And apart from the 2.77 ratio. All the centres and gears were interchangable. Share this post Link to post Share on other sites
deankxf 20,288 Posted June 19, 2019 31 minutes ago, xwagon said: My understanding was that 28 spline did not start till after the xf? And that all bw diffs before that were 25 spline. And apart from the 2.77 ratio. All the centres and gears were interchangable. i am 99% sure if they had 351s they got 28 spline axles and 4 pin pre XF. no XF would have got 28 spline to my knowledge. Share this post Link to post Share on other sites