hoping someone on here can help me out. have 1979 d7g and I'm having issues with hydraulic oil pushing into my motor. wondering if this is a venting issue on hydraulic system if its pressuring up to much and pushing through rear engine seal or if there is other issues that could cause this maybe something more common? also how big of a job is it to change this seal? just picked this machine up this spring and don't have service manual for it so not sure where to start diagnosing any help is appreciated. thanks
I would think the problem would be bad seal in hydraulic pump or even worse a bad pump it's self. A full S/N of the dozer and the hydraulic control would help. The hydraulic tank should have a tag on it giving a model and S/N I believe for that age of machine. I could be wrong on the hydraulic control, but at least a full S/N of D7G would be a good start!