timfreecom
Active Member
hi guys,just to say my vans done 140k mainly driven motorway miles,original vcu ,its 5 years old,thinking time might be a factor on vcu wear ? tim.
When I test drove the 2002 TD4 Auto I've just bought, being mindful of this 70 000 mile figure,( its done 72K,) I'd read about here and elswhere, I did a few full lock turns at tickover speed both forwards and reverse. I could only detect the slightest braking effect which vanished as soon as the steering lock was reduced.
I guess that the loss of flexibility in the coupling is gradual, the stiffness gets worse with time and milage? As I have to use full lock whilst reversing, daily, to get into my parking space at home, perhaps noticing a gradual increase in this braking effect with time could be used as an indication of failure? How stiff is dangerous to the IRD/Diff I wonder?
I guess that the loss of flexibility in the coupling is gradual, the stiffness gets worse with time and milage? As I have to use full lock whilst reversing, daily, to get into my parking space at home, perhaps noticing a gradual increase in this braking effect with time could be used as an indication of failure? How stiff is dangerous to the IRD/Diff I wonder?
Harold 4x4
Active Member
As a general observation, having read the plethora of information on here and having spoken via telephone to various land rover specialists.... bearing in mind I am nothing more than a hobby-mechanic at best.
A torque test of any kind will only give you a 'number' which is relative to.... nothing!
Even if you had the original torque from a brand new vcu and then compared it to the torque of various other 'used' vcu's it would simply be another number on a wrench. No more no less.
It doesn't help with warning you of an imminent 'breakdown', or catastrophic failure, or help with diagnosing any other drivetrain issue.
As a test it would simply be a comparison of torque numbers without any relative consequence.
Just my twopenceworth.
Thanks for all the responses.
A torque test of any kind will only give you a 'number' which is relative to.... nothing!
Even if you had the original torque from a brand new vcu and then compared it to the torque of various other 'used' vcu's it would simply be another number on a wrench. No more no less.
It doesn't help with warning you of an imminent 'breakdown', or catastrophic failure, or help with diagnosing any other drivetrain issue.
As a test it would simply be a comparison of torque numbers without any relative consequence.
Just my twopenceworth.
Thanks for all the responses.
ming
SPACE TWOT
Yer all talk you is. . . . .
Just put viscous 70000 miles in google. Plenty of RECOMENDATIONS on there. Like Harold said. i would rather listen to someone in the know and who makes a living from refurbishing these units than someone on a forum who thinks they may know. Just like car manufacturers recomend a service every so many thousand miles. Most people dont service theire car at the recommended mileage due to one reason or another. But the service interval is still recomended. So once again you seem to have twisted my answer to Harolds question as it was the word RECOMENDED that i used and not, "you must".
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ming
SPACE TWOT
FFS calm down will yer ,if yer that worried just fit a new wun, flippy man was only giving his opinion ,if you dont like the thoughts and help on this forum then feck off. . . .
FFS calm down will yer ,if yer that worried just fit a new wun, flippy man was only giving his opinion ,if you dont like the thoughts and help on this forum then feck off. . . .
:hysterically_laughi:hysterically_laughi Im calm. And im not worried. I just fitted a new one. What makes you think it was me who needed a new one. Not reading all the posts?? i was just giving my opinion to a question. :doh: isn't that what forums are for?? Geezzzz, you landy owners need to get laid more often :mooning:
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ming
SPACE TWOT
RichM
Well-Known Member
There's a lack of information about this.
As we all know, the VCU/IRD ratio was changed circa 2001. Therefore, do newer VCU's need to be replaced at the same mileage as older ones?
Initial VCU problems were the result of a design flaw. This issue was addressed, even though it doesn't mean that newer VCU's are bullet proof. With that logic in mind, does that mean to suggest that VCU's built after 2001 have a longer lifespan?
As we all know, the VCU/IRD ratio was changed circa 2001. Therefore, do newer VCU's need to be replaced at the same mileage as older ones?
Initial VCU problems were the result of a design flaw. This issue was addressed, even though it doesn't mean that newer VCU's are bullet proof. With that logic in mind, does that mean to suggest that VCU's built after 2001 have a longer lifespan?
Harold 4x4
Active Member
:hysterically_laughi
Absolutely! And, there is still no specific information on what the lifespan is of any VCU - there are only recommendations as to when it is advisable to change it.
All very confusing!
Going by the few answers to mileage etc. and with mine also on 109k miles I might just keep going until I feel the characteristics of the car become noticeably unacceptable.
Northern Irelander
Well-Known Member
Yes a fair point, the earlier ratio was 0.8% difference, it was Taipan who jacked up all 4 wheels to witness a 1 in 120 rotation difference between front and back (IIRC it was in one of the mega threads on 2wd/4wd)
If tyres are the same size, then thats a 1 degree slip in 120 degrees or 3 degrees in a full 360 rotation (someone correct me if I'm wrong here)
According to here The Viscous Coupling
The VCU should lock in under a quarter turn, which is governed by pressure/expansion (Silicone volume is around 84% remaining 16% air)...see attachment
Having looked at this again and with recent discussions, could the new ratio be negligable on the VCU....................I dunno, just floating some ideas............light bulb fizzles out
Attachments
NI - cant find anything about testing a VCU in the Rave - at least not in my NAS version.
Northern Irelander
Well-Known Member
mmmmmm!...........it was deffo mentioned on LZ (Freelander forum) by another member, stating Raves method.
Never even used Rave myself, the ISO software takes over the PC, nightmare to remove :doh:
TD John
New Member
Hi NI - searched the 2003 std Rave for VCU testing and found nowt.
If your pc's gettin stuffed by Rave then your not doing it right.
Mine runs by putting the cd in and starting the RAVE.exe file, starts acrobat4 from the disk anorl.
Even runs like that from HD or a pen drive??
If your pc's gettin stuffed by Rave then your not doing it right.
Mine runs by putting the cd in and starting the RAVE.exe file, starts acrobat4 from the disk anorl.
Even runs like that from HD or a pen drive??
Chaser
New Member
VISCOUS COUPLING
Rating:
Max 440 Nm (325 lbf.ft) @75 rpm .....................................
Min 360 Nm (265 lbf.ft) @75 rpm ......................................
As mentioned in previous discussion, it's also about the speed that the vcu will slip without exceeding the max torque.
Rating:
Max 440 Nm (325 lbf.ft) @75 rpm .....................................
Min 360 Nm (265 lbf.ft) @75 rpm ......................................
As mentioned in previous discussion, it's also about the speed that the vcu will slip without exceeding the max torque.
Brill. Thanks Chaser. I assume that is at the VCU. It will be different at the wheel, of course, because of the diff gearing and the friction therein.
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Northern Irelander
Well-Known Member
Great stuff, do you know where those figures were sourced? LR tech bulletin perhaps?
