Ok Cat mechanics, D6R got a thunk in it when changing from fwd to rev and vice versa. Feels like a shaft or something moving in tranny underneath you. Figure it's probably a bearing gone down or something, and expect will probably require transmission removal. I know the fluid has to be drained, the axle shafts removed from the planetary drives, and the whole chunck comes out the back. Aside from these obvious things, any tricks when removing tranny?
Drive shaft from torque to trans. Thats all I got.
I was thinking the shaft also, but you may already have checked that! only tip i have is to remove the ripper shank from the ripper to aloud it to drop down far enougth to let the trans out (if it has one), Dont ask how i know:drinkup
what have you done to verify a mechanical failure? Checked filters and screens for foreign matter? No active codes for shift solenoids or speedsensors? A failure that creates a "thunk" surely must have left some evidence somewhere. Do the easy stuff first.
Nasty shift might not be inside, it might be worth checking the modulating valve ( soft shift ) on the oil feed. tctractors
Those are easy trannys to pull. I would make sure that you dont have a problem with the shift solenoid/valves or speed sensors. The priority valve will cause issues also. I have repaired countless numbers of D6R D6M and other machines that share the same setup in the tranny that clunked when shifted. Check for codes and check the clutch engagement pressure it is adjusted electrically via the powertrain ECM. You then can run a clutch fill calibration and see what happens. As the solenoid valves wear, they sometimes start causing shift problems that can be smoothed out by the calibration. The speed sensors can cause similar problems also. I was working for the local Cat dealer as a field mechanic when these dozers came out, and believe you me, I got a good old fashioned on the job schooling the first month those tractors hit the dirt.
Very good replies guys. I haven't started the work yet, the boss noticed this when he was running the machine, had me give it a quick listen. I already had the floor plate and the seat base out of the tractor to pressure wash the innards. I was planning on removing filters and check for debris, also have a drip at the small square plate at the rear tranny plate, down at bottom of tranny. I've been told you have to drain the oil to remove the small plate. Also, it has some old codes on it, like code for battery voltage low, probably from a time battery went dead and codes have never been cleared. I'm considering having a Cat tech come out and clear old codes and have him listen to the noise, maybe do a few pressure tests as well. I'm more experienced with contractors type equipment and aerial lifts, not so much these type dozers. I find it interesting that speed sensors or priority valves could possibly cause something that feels like this. It's not like a hard shift clunk, as in clutch packs engaging rapidly. You can even feel it at idle and tractor not moving. Be in fwd at idle, select N, then rev, and you can actually feel a rattle under you, similar to the feeling you would get in a truck with a mid shaft carrier bearing bad and get a thunk when you engage the tranny. And I know this isn't definitive, but with the floor and seat plate out, even sounds like the noise is deep in tranny. Not sure when I'm going to do the work, will keep you informed of what I find. Meanwhile, let me know of any other ideas you may have and the procedure for pulling tranny out of the rear. Thanks all.
The quickest way? Send it to Ritchie Bros. nearest auction.
LoL! Naw, man. I can't learn anything that way. I wanna take it apart! :tong
That is true. If you sent it there you would have to put a quick midnight Dupont over haul on it anyway.
The good news is it does not take long to remove it if need be. If it is a speed sensor, you will have to pull it to replace them anyway. I normally pull the shanks on the ripper and lower it down if it has a ripper. It will come out that way but it is close. Really all that has to be done is removing the driveline, pulling the axles from each final and the one in the center if it is diff steer, or the two center shafts if it is clutch steer. Unhook the wiring harness and the oil line on top of the tranny. There is several bolts that hold it in, but leave the two that have the 12 point heads so you dont seperate the the inner housing. Remove the small round winch (PTO) shaft cover and make another one from scratch and weld 2-3 feet of 2" pipe on it. Bolt it on and hook the hoist on the pipe. If it is diff steer, there is a gear set just inside the transmission case that must be slid out to free the tranny. Go in the left final where the axles go with a 1" pipe that has a lip welded on it to grab the gear set and pull it to you about 1-2 inches, it wont go far. The tranny will pull out, and the front of it has rollers it will roll out on. There is a bolt hole on top you then can put an eyebolt in and finish getting it out of the way. You will be suprised how easy it is. Most of the dozers in my area have winches, so that just adds to the trouble for me usually. Back when these things first came out, the speed sensors went out all the time. I got where I could show up at 8:00 AM and R&I the tranny, replace the sensors and be done in time for lunch. You may very well have a serious failure in there, but one would be suprised how bad those things sound when the control systems are out of order. As you said, cutting the powertrain filter and looking for metal would probably tell the story.
You might check the U joints on the drive shaft before getting too quick on jerking the thing out. That's kind of what the rumble sounds like. I don't for the world understand why they had to have electronics on a dozer transmission. It doesn't do anything to save fuel and I haven't seen any longer life on the transmissions. I do know the electronics will cause many shift problems but they almost always show up with fault codes. If you have a live code the monitor will show ServCode or something like that. Good Luck!
Yep, u-joints are first thing I checked John C. Nice and tight. Thanks for the info Lonestar. Hope the boss will turn me loose on it in the next few weeks. I think it would be smart to have a Cat tech check the codes on it. I know some are old, but there may be some info there that they could work with. Assuming we do pull the tranny, and find a mechanical failure, would it be wise to replace speed sensors while it's out? Or are they relatively spendy?
There is a hard rubber coupler under the floor board on the right hand side when your setting in the seat.There is a shaft that comes out of the flywheel housing that powers the transmission pump that mounts to the transmission. The rubber gets cracked and things gets out of line and balance and will made clunking noise.There is a bearing and seal in the front that also goes bad,usually will leak oil out there.There is a two piece cover over the coupler,i think four bolts hold it on.If you remove the covers you will be able too see things better. Also agree about the speed sensors,also if it is idleing too slow the brake will try to come on,what is the speed it is idleing.Like if you decelerate it drops too low of idle the brake will try to come on.I'm thinking needs to be 900 plus. Your other men knows more about that.It might be something simple.Hy it could be a D6H with a low power and smoke issue you know!!!!!!! Good luck:usa
As far as speed sensors i think there is two,they will run on one if one goes bad.My D6R needs them replaced,right now it is still working with the one.I was just waiting for a chance to replace them. Replace both no matter what! Long winter again, no shop and now is time to get moving before the planters start rolling,so will have to wait unless it goes down then it will have too happen.:usa
Sorry for not getting this sooner. Been busy! Great advice from Per Eriksson, ALWAYS check screens and filters before you begin pulling components. Also, sounds like LonestraCobra knows the ropes on this machine…all good tips that we too have experienced. The only thing I would add is that before disabling the machine make sure the master links on the tracks are in a position that you can split them and remove the finals and brakes just in case you find that you have to go deeper after pulling the trans, otherwise you will lose lots of time waiting on a transmission so you can start it back up to set them up. Second is that often the left differential steer planetary will slide inward and bind the trans while pulling it out. Seen a lot of gears and carriers broken because the trans will actually begin to come out easily for a half inch or so which makes the mechanic think he’s home free and then it hangs up and out come the forcing bolts….OUCH! All you have to do is push the carrier back with a long pipe through the hole in the right final after the axles are removed. Let us know if we can help with parts or exchange components.
I sorted a thumping Gear Change on a D6RLGP tractor this week, the fault was with the Coil on the Priority Valve, this is outside the G/Box under you left Boot as sat in the Cabin, half way up the casing. tctractors
atcoequip....if you can acess the serv. codes on the monitor....i have et and sis on my laptop....only the 113 codes they r for the power train..i can tell you what they r instead of paying cat to tell you...
Thanks MrKomatsu. If I get a chance next week, I'll jot down the codes and send you a PM. Covered up with other machines right now, but I'd like to get the repairs done to the D6, another one of those unfinished jobs right now. :yup
10-4...just let me no.....take care..
finals make funny noises sometimes
i think your problem is final drive. check oil from the final drives and look for metals before you take anything apart
or if you dont want to loose the oil get a flex magnet and put it in through the filling plug to check for metals
How much play does the left side diff planetary have? Is it suppose to be able to come out from the inside with tranny removed?