General Car Related Discussion. To discuss anything that is related to cars and automotive technology that doesnt naturally fit into another forum catagory.

Cosworth 7” rear diff backlash

Thread Tools
 
Search this Thread
 
Old 16-10-2017, 07:51 PM
  #1  
McCloud 85
PassionFord Regular
Thread Starter
 
McCloud 85's Avatar
 
Join Date: Oct 2004
Location: Gatwick
Posts: 365
Received 12 Likes on 11 Posts
Default Cosworth 7” rear diff backlash

Has anyone got any knowledge on acceptable back lash on the standard 7” LSD rear diff?

I have 18’s fitted to my car and when both rear wheels are lifted off the ground you can turn one wheel around 10cm on the outer circumference before it engages the other wheel. Is this to be expected?

Be interested to know if I should expect the same on the front diff.

I do have videos but have no idea how to upload them!
Old 16-10-2017, 08:05 PM
  #2  
Caddyshack
10K+ Poster!!

 
Caddyshack's Avatar
 
Join Date: Mar 2013
Location: Guildford
Posts: 10,841
Received 1,031 Likes on 944 Posts
Default

Is the front diff lsd as standard? A lot of cossie diffs don't lock well when tired according to threads I have seen.
Old 16-10-2017, 09:08 PM
  #3  
McCloud 85
PassionFord Regular
Thread Starter
 
McCloud 85's Avatar
 
Join Date: Oct 2004
Location: Gatwick
Posts: 365
Received 12 Likes on 11 Posts
Default

Front is just a open diff standard. No LSD as far as I know.
Old 17-10-2017, 09:27 AM
  #4  
Marc sierra
Advanced PassionFord User
iTrader: (1)
 
Marc sierra's Avatar
 
Join Date: Oct 2006
Location: Netherlands
Posts: 1,889
Received 157 Likes on 143 Posts
Default

I think this is also due to play in the CV joints. In total there are 4 in between the wheels and each one doesn't need that much play to get 10 cm on circumference of the wheel. You could check by looking at how much the driveshafts and diff stubshafts turn compared to each other.

Last edited by Marc sierra; 17-10-2017 at 09:28 AM.
Old 17-10-2017, 04:49 PM
  #5  
Caddyshack
10K+ Poster!!

 
Caddyshack's Avatar
 
Join Date: Mar 2013
Location: Guildford
Posts: 10,841
Received 1,031 Likes on 944 Posts
Default

I have a quaife front diff and when you park the car it feels have the handbrake on, I am pretty sure it would do as well in the snow as my Range Rover with the way the 4 wheels all lock up.
Old 17-10-2017, 06:11 PM
  #6  
McCloud 85
PassionFord Regular
Thread Starter
 
McCloud 85's Avatar
 
Join Date: Oct 2004
Location: Gatwick
Posts: 365
Received 12 Likes on 11 Posts
Default

The majority of not all the ‘slack’ seems to be in the diff, i.e movement between the stub axles turning to the prop then turning.. which I’m assuming is the sock in the crown and pinion gears. Doesn’t affect the driving at all and it doesn’t bother me as long as it’s not a sign of something needing attention.
Old 18-10-2017, 10:33 AM
  #7  
20/20 vision
Regular Contributor
 
20/20 vision's Avatar
 
Join Date: Nov 2007
Location: it's not where you are, it's where you've been and where you hope to be
Posts: 267
Likes: 0
Received 16 Likes on 16 Posts
Default

it can be difficult to determine where the play is coming from but clamping big mole grips around the drive shafts then jamming those up against a chassis / wishbone thingy then turning another thingy like wheel or diff drive-flange helps to isolate the cause.




All times are GMT. The time now is 01:04 PM.