I have a Bomag K300 Compactor with a transmission issue. Machine works as it should in reverse, plenty of power, no slip in all 3 gears. In forward, it will engage in 1st gear but slips once its put to load, example traveling up hill or up ramps. We are gonna pull the transmission and tear it apart. I'm assuming its the Forward/Second Clutch group that will need to be rebuilt. My question is am I heading in the right direction? I don't want to tear this apart if I'm missing something here. Figure some of you older guys might have some experience with this old beast of a tranny. Thanks for your help!
Have took any pressure checks ? I can look to be of I have off book on it .
It kind of sounds more like the forward clutch pack to me. You might think about pulling the filters and look for clutch material or pieces of metal before you pull the box. As tool_king says, a pressure check might provide a little more information on what has to be done before going to all that work.
What is your email address ? I have a pdf manual I can email you .
Thanks for the replies! my email is [email protected] I’m not sure exactly were to test the pressures at. I mean I can test the pressures at the charge pump or oil cooler, but I’m guessing I would be looking at the wrong place. If the machine works perfect in reverse, then I’m assuming the pressures to the transmission are good. This is why I’m thinking the forward clutch is the culprit. Is there a way to test the pressure on the oil going into the transmission front be control valve when it’s in forward vs reverse? This might help diagnose I did read one old report of a guy having an issue that an oring was leaking where the oil passage passed thru I believe it was the front plat. If there are separate forward and reverse oil passages (I assume) then is possible something like this could be the problem.
The manual from tool_king should provide most if not all your answers.
We did a pressure test today and pressures were consistent. Same forward and reverse in which ever gear we selected. I also actually operated the machine with the guage visible. In forward 1st gear, it will engage when I go easy on the throttle and when it engages into gear I’m able to slowly increase the throttle and it operates. If I lay hard on the throttle in forward at any time, the machine slips out of gear. The pressure guage doesn’t change at all whether the machine kicks into gear or slips out. 2nd gear has almost no chance for the machine to engage. Just slips. In reverse, the machine works as it should. It pops into gear immediately and I can hit the throttle as hard and fast as I want with no slip and plenty of power. I can start immediately in 2nd gear with power. All this leads me to think it’s the forward clutch pack. We started prepping the machine to pull the engine and trans tomorrow.
Sounds to me like you made a logical progression to come to a course of action. Be careful and good luck tomorrow.
Manual was emailed to you .Manual will show you full breakdown and repair .
For some reason your email kick back when i tried to send you the manual.
Email went through. Thanks for the manual. We pulled the motor and trans today. Tomorrow I break into it!
Ok great .Let us all know what you find out . thanks
Looks like you are on the right track. Check your input gear also. They are famous for flaking the metal off the gear itself.
So today I broke into the trans. All the gears I came across looked solid and didn’t looked flakes or grooved. I took apart the forward and 2nd clutch group and found the clutch piston on the Forward side cracked. The actual clutch plates looked good. This was the side I replaced back quite a few years ago. The second gear side looked more worn but still not that bad in my opinion. The second side piston and seals looked good. We did notice something strange on the drum. The second side of the drum gears look different than the Forward side. There looks to be a 1/4” long slight grove on the forward side. It looks so clean that I thought it was machined that way, but now I think that omit wore that way somehow. I don’t think it’s right. Maybe someone here can verify this for me. This is a pic of the 2nd side of the drum. Here you can see a pic of the forward side. You can see the area that I consider wear. this is the crack on the forward side piston I was talking about. This is definitely not good. I’m currently looking for a replacement drum and new piston for the forward side.
Bottom of the splines look burned. Worn sections look like some tangs on the frictions are broken off when it spun through them at some time. You made good time getting to this point.