• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Differential ident.

Share this page

M

MCS

Jedi Warrior
Offline
Hello,
Can anyone positively confirm that both of my sprite differentials are 4.22 ratio?
Here are the case numbers ATA 7335 and BTA 548.
I have looked in my Haynes restoration manual; it does have some case numbers but not my specific numbers.
Thanks Phil
 
Casting numbers are meaningless. There is a small pad above the mount for the rear brake line fitting, right side of diff. housing. On it are stamped two numbers. Divide the larger by the smaller to get the ratio that was originally installed.
A 4.22 is stamped 38/9.
This will only work if the original ratio is installed. The only ways to be positive are to either remove the center section and count the teeth on both the ring gear and the pinion, and do the math, or hold one side while turning an axle and counting the turns the pinion flange makes.
Jeff
 
Thanks for the info, the diff case numbers are listed in the Haynes restoration manual. I would think somebody must have a case diff number list.
Phil
 
MCS said:
I would think somebody must have a case diff number list.
Phil
Click to expand...

Phil, anything from a 3.5 to a 4.55 will fit into the same case, so the case numbers don't mean anything regarding the ratio.
Jeff
 
yeah I am aware of the case being all the same , just thought there might be a range of diff numbers for each ratio stamped on the case. I guess as you said the gears can be changed. I have 2 diffs both are stamped as 4.22 by there case number. Just to confirm your ident method, jack her up and hold one wheel stationary and turn the other and then count drive shaft revolutions. Was thinking a higher gear ratio might be nice for highway driving.What seems to be the perferd ratio with the 4 speed trans. Sure wish I could find a 210 trans at a ok price.
Thanks Phil
 
Gear info is stamped on the case as someone said, however the gears may have been changed in the last 40 years or so.
 
ok I will go look again
Phil
300 miles on my new engine it runs so nice if only I could get my Hap ported head, he is a very busy guy. Should be soon i hope
 
Back
Top