Differential case side bearings

[angelw]

Hello Colin,
Is your Gear Set a new, After Market set?

The backlash value engraved on an original Crown-wheel/Pinion set, out of a Salisbury diff, in my experience, is nearly always correct and is always very close, if not smack on, with regards to the witness mark relating to backlash.

Best regards,

Bill

[lowact]

Hello Bill, CWP is new, so there is no backlash etched on it. For the Salisbury’s you have reconditioned, what does the etched backlash values look like? On my OEM Salisbury CWP the head of the pinion is marked as per the workshop manual, the +9 being the pinion setting, 3116 the CWP matched set id number:

On the rim of the crown-wheel is the matched set id number (3116) and some indecipherable scrawling:


There is also some etching on the shaft of the pinion, I interpret “-5 N”. Searching for a question to this answer, there were 5 thou less shims under the diff non drive side brg ...


By comparison, here is my new CWP, only etchings are the matched set id numbers (202, not shown in photo):

Imo Quaife are excellent quality. Modern tech may be the reason it appears far superior; by comparison my 50 yo Salisbury is very ho-hum, e.g. here is close up of the pinion showing as manufactured sharp, chipped edges to the teeth. If SNGB had sent me this I would not have accepted it.

The only etchings (not in photo) on my Quaife CWP are the matched set id numbers (202) same as is stamped (as show in photo). I.e. there is no backlash value, maybe I’ll etch on after the diff’s told me what it needs, hopefully close to 0.1 mm

[Doug Buchan]

Hi Colin,
The Churchill SL 14-3 set of dies requires the SL 14 hand press... or at least the base for use with a shop press.
When Steve mentioned a clamshell type puller, I think he was referring to something like this.
Never tried one but they seem easier to use than the awkward Churchill set up.

[lowact]

Should I leave it or should I fiddle some more?
Diff renewal, new seals, brgs, cwp (crown wheel and pinion), is coming along nicely albeit slowly with covid delays.
Per the manual the backlash needs to be not less than 4 thou. inch; the actual value (consequence of the original setup) “should” have been scribed onto the gear.
As previously there is nothing decipherable as diff backlash scribed onto my oem cwp. Instead I am assuming my oem diff backlash was originally 7.5 thou inch, based on the tags that were attached to my diff , i.e.:


As previously I am interpreting that diff backlash is unique to each diff housing/cwp combination. Therefore, because I’ve changed my cwp, the recorded backlash is no longer applicable. Means I have to resort to a trial and error process until the tooth contact pattern is acceptable and the backlash is not less than the 4 thou minimum.
Trial #1 is with the original shims, 20 thou on the drive side and 15 thou on the non-drive side. Contact pattern looks good, backlash is 10 thou:


Job done, or is it?
Moving shims from the ND side to the D side would reduce the backlash and would also move the contact pattern closer to the toe, both notionally better, but not if I go too far …
Originally there were 3 thou shims available. now there are not. So, short of making my own shims, the least I can move is 5 thou, this may be too much …
Does anyone have any experience of the rate/extent that swapping shims changes the backlash and moves the contact pattern?
I reckon I probably should leave it …