jamesmartin
Well-Known Member
the props coming in and out would have to be doing different speeds
they are
jamesmartin
Well-Known Member
only by ratio of front and rear drive from ird
exactly, and that is why the VCU is designed to slip.
Freelaner
Landy Driver
by distributing power to the rear when the front wheels lose traction
Freelaner
Landy Driver
int that why the gearing is different between the IRD and VCU?
there is no gearing in a VCU
diff i meant
jamesmartin
Well-Known Member
ratio difference is in ird
no the difference in gearing is completely done in the IRD.
they changed the IRD ratios.
Freelaner
Landy Driver
early FL:
rear diff is 4.200 (petrol) 3.647 (diesel)
late FL: 3.182 td4 manual, 2.91 td4 auto, 4.20 K series, 3.66 kv6
IRD is a bit complex
IRD to IRD countershaft 0.828:1
IRD countershaft to front driveshaft 1.762:1
IRD countershaft to propshaft 0.553:1
IRD ratios (late) td4 + K 1.458:1
KV6 1.351:1
early IRD same as late k for all engines
* All according to manual * which I'm not certain I beleive. Cant find a TSB about the rear diff change, though I can find diff part numbers for early and late versions
So drive comes in, and multiplies up to IRD countershaft. Then ratios output to front shafts, and propshaft with the ratios listed. Which makes it all a bit daft, if thats true
So 1.458 = 0.828 x 1.762
The weird thing is, according to the internet:
"They're all 3.21, except some early ones which were 3.19"
And Ashcroft only list two part numbers - early & late, late having beefier bearings.
rear diff is 4.200 (petrol) 3.647 (diesel)
late FL: 3.182 td4 manual, 2.91 td4 auto, 4.20 K series, 3.66 kv6
IRD is a bit complex
IRD to IRD countershaft 0.828:1
IRD countershaft to front driveshaft 1.762:1
IRD countershaft to propshaft 0.553:1
IRD ratios (late) td4 + K 1.458:1
KV6 1.351:1
early IRD same as late k for all engines
* All according to manual * which I'm not certain I beleive. Cant find a TSB about the rear diff change, though I can find diff part numbers for early and late versions
So drive comes in, and multiplies up to IRD countershaft. Then ratios output to front shafts, and propshaft with the ratios listed. Which makes it all a bit daft, if thats true
So 1.458 = 0.828 x 1.762
The weird thing is, according to the internet:
"They're all 3.21, except some early ones which were 3.19"
And Ashcroft only list two part numbers - early & late, late having beefier bearings.
Diesel Do
Well-Known Member
What's it split? IRD splits it front to rear? It just provides drive in wheel spin situations
Freelaner
Landy Driver
it's not a diff lock
Diesel Do
Well-Known Member
No it's not, it's a limited slip diff disguised as a vcu. So the greater the slip, the more heat generated the less slip allowed to the point of virtually locking, transmitting permanent drive to the rear wheels then it'll cool allowing slip again as traction is regained!
