Hi Guys I am new to this forum. I am from Elmvale on Canada eh! I am seeking some advise for help with a Cat 416 Backhoe. I can post the serial number if it would be needed. This is late 80s early 90s model. It has the perkins engine and spicer 4 speed transmission. The trouble I am having is with the 4wd engaging. I have check the solenoid and it gets power and does activate. It would seem this moves a valve of sorts as when I would push on the plunger in the transmission it does not activate any gear so to speak. I do know there is a suction screen in the trans which I will look at to see what is in it. I have changed the transmission fluild and filter end of last summer. unit doesn't get used in the winter. I did change the front u joints and it seemed it was shortly after that the 4wd did not work. when the machine is in the air the front will engage and turn if there is not load on the wheels when the load is introduced the wheels stop. forward reverse seem to work fine. I am looking for some direction as to what to look at and for. Does anyone have a parts breakdown or pages from a service manual. Thank you in Advance. Brady
When the wheels stop, is the driveline still turning, or not? If the driveline turns but the wheels don't, the problem is in the front axle somwhere, not the transmission.
Hey yes the drive line stops. Not power coming out of the trans to the front drive shaft yoke.
The solenoid for the 4x4 shift sends oil pressure to engage a clutch pack in the bottom of the trans. I would suspect the clutch pack is worn out or the application pressure is low.
Hey thanks so much for the info. I have finally got it apart. There was a small amount of debris in the suction screen but not enough to be a concern i would say. I pulled the 4wd clutch pack off the bottom and don't see any wear on the plates or the discs. They look new still have cross hatch on the plates. So I would suspect then issue with application pressure. I know the solinoid works but I am not sure if it just has to over come the spring on the plunger or the full force of the oil pressure. Perhaps I should check the solinoid on the bench and see if I can depress when activated. I am not sure how or where to check the pressure. It's same fluid as the forward reverse and they were fine so maybe I am back to weak solinoid if it needs to overcome the oil pressure. If you have time let me know your thoughts. Thank u much Brady
Hey so I had some time today to look into this a bit further. I found nothing wrong with the clutch packs they look like new so what I am figuring is that the solinoid is not strong enough to force the plunger to direct the oil flow. When I activate the solinoid if I have the rod at the end depressed then when power is applied it will not come out. She inlet off slowly then the rod will push out but it take very little force to push it back in. I would think given the size of the solinoid it should exert more force that what it would seem be. I think I will look if the dealer has one hope it solves the trouble. Let me know if you can think of something else