GTCB-chris
05-07-2009, 04:47 PM
Honda's Real Time 4WD system on the CRV utilizes a Dual hydraulic Pump Rear Differential and 4WD Transfer case. The transaxel operates the front wheels during normal conditions then automatically transfers power to the rear wheels when needed, without the driver engaging the system. To allow the ABS braking system to work when the CRV is engaged in four wheel drive operation the 4WD will turn off if the brakes are applied.
http://www.awd.ee/images/honda_geroter_pump.jpg
first generation (1996-01) rear differential
http://www.hondanews.com/media_storage/GIF/07CrvLine_15.gif
Thrid generation (2007-2010) rear differential.
its a dual pump system, when there is a different between the two pumps, it opens a valve, pushing the multi clutch pack engaging the rear wheels.
when the rear differential is low on fluid, or if the dual pump fluid is worn out, the clutch pack will "groan"
basically when the front wheels slip, it causes a difference in pressure between the two pumps in the rear differential ( one pump is powered by the propeller shaft, and the second by the rear half shafts ) the difference in pressure pushes open a valve, and pushed the clutch pack toghter causing power to be sent to the rear shafts, once traction is restored to the front wheels, or if the differential over heats, the valve is closed and the clutch pack is released. the Dual Pump Fluid II not only powers the hydraulic system, but it also lubricates and cools the differential. the rear differential also has a "breathing tube" on the top. after so many miles ( it depends on driving habbits, conditions, and debris/contaminates in the fluid ) the fluid needs to be replaced, the clutch packs will eventually need to be burnished, and the differential may need to be flushed.
bad fluid or clutch packs will cause a groan, or a grinding sound. but only when the clutch packs are engaged.
to check the fluid level, unbolt the top filler bolt and stick your finger in, you should be able to feel fluid level with the treads. to drain the differential open the filler bolt, and the lower bolt, replace drain ( lower ) bolt and fill with about one and a half bottle of dual pump fluid ( about $8.50 US ) make sure fluid is level with filler bolt. drive about fifteen minutes and check fluid again. if you have been having problems you may want to either get clutch packs burnished or you could repeat the changing process at least 3 times, until when emptying the differential all that comes out is new fluid.
-chris
http://www.awd.ee/images/honda_geroter_pump.jpg
first generation (1996-01) rear differential
http://www.hondanews.com/media_storage/GIF/07CrvLine_15.gif
Thrid generation (2007-2010) rear differential.
its a dual pump system, when there is a different between the two pumps, it opens a valve, pushing the multi clutch pack engaging the rear wheels.
when the rear differential is low on fluid, or if the dual pump fluid is worn out, the clutch pack will "groan"
basically when the front wheels slip, it causes a difference in pressure between the two pumps in the rear differential ( one pump is powered by the propeller shaft, and the second by the rear half shafts ) the difference in pressure pushes open a valve, and pushed the clutch pack toghter causing power to be sent to the rear shafts, once traction is restored to the front wheels, or if the differential over heats, the valve is closed and the clutch pack is released. the Dual Pump Fluid II not only powers the hydraulic system, but it also lubricates and cools the differential. the rear differential also has a "breathing tube" on the top. after so many miles ( it depends on driving habbits, conditions, and debris/contaminates in the fluid ) the fluid needs to be replaced, the clutch packs will eventually need to be burnished, and the differential may need to be flushed.
bad fluid or clutch packs will cause a groan, or a grinding sound. but only when the clutch packs are engaged.
to check the fluid level, unbolt the top filler bolt and stick your finger in, you should be able to feel fluid level with the treads. to drain the differential open the filler bolt, and the lower bolt, replace drain ( lower ) bolt and fill with about one and a half bottle of dual pump fluid ( about $8.50 US ) make sure fluid is level with filler bolt. drive about fifteen minutes and check fluid again. if you have been having problems you may want to either get clutch packs burnished or you could repeat the changing process at least 3 times, until when emptying the differential all that comes out is new fluid.
-chris