Classic Audi Technical Mech/Tech Transmission » CQ rear diff stuck on....

Reply
 
Thread Tools Display Modes
Old 14-06-17, 02:15 PM   #1
MS-L
Grown up member
 
Join Date: Jan 2016
Posts: 70
Default CQ rear diff stuck on....

As above.
I've not driven the car for ages and took it for a little spin to today to check everything works ok before I put it up for sale.
Anyway the rear diff engaged as normal but wont disengage.
Any thoughts?
Something stuck maybe?

Thanks
MS-L is offline   Reply With Quote
Old 14-06-17, 03:19 PM   #2
Hanuman
Trickster
Classic Audi Club Member
 
Hanuman's Avatar
 
Join Date: May 2009
Location: Heckling from the cheap seats
Posts: 6,646
Default

The locking mechanism is vacuum operated. It's possible that it can't move against a build up of crud around the shaft.

Is the operating rod intact? Due to the build up of crud, the shaft can be prone to rotting through.

(The two above are easily checked within a couple of minutes on ramps)

Sticky internals. I've not come across a rear diff doing it, but several centre diffs had played up unlocking, until the transmission is unloaded. Usually going in reverse a few feet.
__________________
enjoying a curry and a tiger beer
Hanuman is offline   Reply With Quote
Old 14-06-17, 03:32 PM   #3
MS-L
Grown up member
 
Join Date: Jan 2016
Posts: 70
Default

Thanks. I'll have a crawl about underneath later and see if the rod is stuck.
It engaged ok but won't free off.
MS-L is offline   Reply With Quote
Old 15-06-17, 09:12 AM   #4
MS-L
Grown up member
 
Join Date: Jan 2016
Posts: 70
Default

Right then.
The lever moves back and forth but is rather stiff. I'm assuming that with the switch set to off the vacuum fades away and the lever moves back to off under it's own steam as it were, or should the vacuum pull it back?
There is loads of pressure to push it into the on position but nothing pulling it back.

Any ideas?
MS-L is offline   Reply With Quote
Old 15-06-17, 09:22 AM   #5
msh
4 ring whore!
 
msh's Avatar
 
Join Date: Jun 2008
Location: Rucava, Latvija
Posts: 3,803
Default

Quote:
Originally Posted by MS-L View Post
Right then.
The lever moves back and forth but is rather stiff. I'm assuming that with the switch set to off the vacuum fades away and the lever moves back to off under it's own steam as it were, or should the vacuum pull it back?
There is loads of pressure to push it into the on position but nothing pulling it back.

Any ideas?

Yes. After all, there is no spring pulling it back, both outside and internally, so it's up to actuator to do that. Check the switch and hoses, presuming we're talking about B2.
msh is offline   Reply With Quote
Old 15-06-17, 09:26 AM   #6
MS-L
Grown up member
 
Join Date: Jan 2016
Posts: 70
Default

B2. Yes.
Thanks. So the actuator pushes and pulls? I think mine may have stopped pulling.
Plenty of push but no pull.
MS-L is offline   Reply With Quote
Old 15-06-17, 03:45 PM   #7
msh
4 ring whore!
 
msh's Avatar
 
Join Date: Jun 2008
Location: Rucava, Latvija
Posts: 3,803
Default

Actuator has two hoses connected because each is connected to one side of diaphragm or whatever is inside. Like I said, check if the diff lock switch puts vacuum to correct output when lock disengaged and if there isn't a leak in the hose between switch and actuator.
msh is offline   Reply With Quote
Old 15-06-17, 03:59 PM   #8
MS-L
Grown up member
 
Join Date: Jan 2016
Posts: 70
Default

Thanks.
I'll check to see if all the pipes are still in one piece. It has only just started doing it after quite a long lay up.
MS-L is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT. The time now is 06:08 AM.

Powered by vBulletin®
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright ©2007-2008 Classic Audi | Site by Roadrunna