The Freelander has 3 main drivetrain problems areas, the Intermediate Reduction Drive (IRD), Viscous Coupling (VC) and the rear differential.
The reason for this is the front wheels on the Freelander are driven faster than the rear wheels so it handles well, like a front wheel drive car. To accommodate this ratio difference, a VC is fitted inline with the rear propshaft which thus is constantly slipping.
On the earlier models this ratio difference was too great resulting in the viscous coupling working overtime and failing by siezing solid. When the viscous coupling is too tight or seized solid the front tyres are fighting the rears as the transmission is "winding up", initially this just wears the tyres (causing a "saw tooth" effect) but it also puts increased load on the IRD and rear diff as they are fighting each other causing rapid wear on both and ultimately failure of one or both.
The earlier diff fitted to the Freelander was TVK100380, due to premature failing by the problems created by the viscous coupling siezing this was superceeded to TVK000180 which has larger journal bearings and is thus stronger.
The IRD ratios changed in 2001-02,
Old IRD ratio - 1.458:1
New IRD ratio- 1.467:1 *(every Freelander from VIN YA999999)
Some of the early FL have different final drive ratios as well:
Petrol engine - 4.200:1
L-series eng - 3.647:1
Td4 engine - (manual) 3.182:1, (auto) 2.910:1
Some new ratios >2001:
IRD input shaft to IRD countershaft - 0.828:1
IRD countershaft to front driveshaft - 1.762:1
IRD countershaft to prop shaft - 0.553:1
IRD ratio > 2001
TD4 - 1.467:1
1.8 - 1.467:1
KV6 - 1.359:1
The MGF box and FL1 1.8i box have the same final drive ratio of 4.2 (15/63)
The ratios are the same in 1st and 2nd, it is 3rd 4th and 5th with different ratios.
MGF
1st 3.250 (12/39)
2nd 1.894 (19/36)
3rd 1.307 (26/34)
4th 1.033 (30/31)
5th 0.848 (33/28)
FL1 1.8i
1st, 2nd as above
3rd 1.222 (27/33)
4th 0.848 (33/28)
5th 0.648 (37/24)
PG1 box codes
FL1 = S4EM
MGF 1.8 VVC = G4BSV
MGF 1.6, 1.8i = G4BPF
