Jump to content
Click here if you are having website access problems ×

diff fitting on new SLR

Julian Thompson

Recommended Posts

Wonder if anyone has any thoughts on this one:


I fitted the propshaft first then bolted the diff up and torqued the blue bolts in situ - seemed a lot easier becuase that propshaft is damn close!


Anyway - got an issue with alignment on the diff. Done the spacer washers on the bottom first as suggested - got to + 2mm towards the RHS with 3 thick and 2 thin washers both sides. The top bolt is tight - a real tinker to get in and there is a visibly bigger gap on the LHS - we are talking + 5mm to the RHS.


Should I;


1) Remove some LHS washers on the lower mount - result will be lower mount - 2mm to the LHS overall and this will give + 3mm to the RHS at the top. Ie a bit of twiddling should see me within tolerences.


2) Leave the bottom or adjust to 0mm tolerence and then twist the diff to the LHS by say 3-5mm at the top to get 0mm at the top but in doing so pre load the bushes a lot - surely a bad idea.




Any thoughts?

Link to comment
Share on other sites



First of all, congrats on the new baby!


It's some 18 months back I built my de dion car but the diff was a bugger. I don't remember us having horizontal alignment problems but then I recall we only measured from the chassis tubes that pass under the DD tube to somewhere identical on either side of the diff, but I think it was at the bottom of the diff. If any of that makes sense!


Basically I don't remember us worrying about centering the top, we just centered the bottom.


Fitting the top bolt was a real pain though - after feeding through from the right it missed the holes on the left of the chassis / diff by some 5mm. Some gentle persuasion was required but I have had no problems in 13,500 miles so far (and that includes the Academy last year and 5 sprints so far this year). Keeping the bottom bolts loose-ish helps a lot.


Good luck!


NN blush.gif

Lotus @ Herts


Edited by - No Nuts on 14 Jun 2002 10:06:11

Link to comment
Share on other sites

Fitting the propshaft first is absolutely the only way to do it. thumbsup.gif


I normally space the top bolt first, with the bottom bolts loosely in place but allowing side to side movement this lets the diff hang from the top bolt. A spray of WD40 should help test assembly of the top bolt.


Are you measuring from the output flanges to the inside of the side chassis rails? This is the important measurement - ignore spacing in the mountings themselves.







253 BHP K-seriesteeth.gif, no gearboxbum.gifid=red>

Link to comment
Share on other sites

When I look at my diff (de dion) from above (or below) the two output flanges are not the same dimension from the centre line of the diff and indeed the two driveshafts are different lengths.


So what exactly needs to be centered and why is it critical to 1mm? The driveshafts (with the LSD) are free to plunge (more than 1-2mm) in the diff output flanges and as long as the profshaft does not foul the chassis in the tunnel, surely one or two spacer washers either way will not make a difference.

If the measurement to centre the diff is critical, there is a casting fillet on top of the diff that runs from the nose to the back of the diff. Is this what needs measuring from each chassis rail?

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...