jd 350c knock

russdog · Aug 1, 2014

To sum it up I was running the machine a while back and I could hear the rattling from the reverser to engine housing. It started getting worse and you could hear it rattle and knocking. After researching it on different forums, I realized it was the isolator. I pulled the engine and sure enough it was worn pretty bad so I started looking for the upgrade isolator and after quite awhile I gathered all the parts and reassembled it with the 350d isolator. I also noticed that the front reverser pump housing had witness marks on it which I figured was from the loose isolator parts. It looked like it was contacting the seal cover. I get it back together and when I started it up there is still a knocking coming from the bell housing. I have checked main bearings and all checked out alright. I also checked the old isolator and flywheel for witness marks from contacting the seal cover and don"t see anything. I am going to pull the motor again and before I do was wondering if anyone has any ideas as to the knocking sound. Thanks,Ken

Roger in Iowa · Aug 1, 2014

Loose flywheel?

JDemaris · Aug 1, 2014

All three versions of those isolators "knock." The ones used in the 350Bs and Cs were were the worse though. None should have any parts that can reach the reverser-pump cover. The splines on the reverser input shaft only go just so far and no drive plate should get past that. Loose springs - yes. The original isolator with the separate springs, anchors, and center-drive-plate with the wear-lining on it was prone to quick wear. I never installed the new 350D setup so cannot comment. I guess you rounded up the new flywheel, isolator, etc.? I assume the same reverser input shaft gets used? You are sure the reverser input shaft is set with the correct endplay (around .002") and the pilot bearing or bushing is in place for the end of the reverser shaft to plug into?

russdog · Aug 2, 2014

I did get the flywheel and isolator from a D model and I didn"t mess with the input shaft as it looked good. I did install a new pilot bearing. I didn"t check clearance with the new flywheel, I assumed it would be fine as it came out of a running machine. The knocking sound is pretty hard and I can not find the source for the contact on the input shaft seal housing. I looked on the old isolator and can see no witness marks. The contact is by the upper left bolt on the cover.[has 4 bolts] No parts were off the isolator but they were quite loose.I will be pulling the motor again in the next couple of days. Thanks,Ken

russdog · Aug 2, 2014

I torqued all bolts according to the manual. It definitely sounds like it is coming from the bell housing. Thanks, Ken

JDemaris · Aug 2, 2014

I rebuilt many of those 350C type isolators. We had many almost new 350Cs have the engine sieze with low hours due to springs flying off and getting wedged between the flywheel and housing. I also rebuilt many reversers and don't recall seeing any marks except those from springs that were flying around. Have you tried spinning the engine over with a screw-driver and feeling for anything rubbing? I also wonder if you could remove the starter and stick a flexible fiber-optic scope in there for a look.

russdog · Aug 2, 2014

When I rebuilt the motor and would turn it over by hand with a pipe wrench on the front hydraulic pump drive snout while installing the rod bearings I could feel some resistance once in a while. It wasn"t real hard but I could feel some. Is there anything in the reverser that would make a hammering sound? I can hear it when cranking with the starter.Thanks,Ken

JDemaris · Aug 3, 2014

I cannot think of anything inside the reverser that can "hammer" unless ir real bad shape. There are five adjustable cone-and-cup bearings in there. If a bearing was bad or real loose - it could knock. Other then that - it's just clutch packs with pistons and drums. The clutch plates are held in place by splines and tangs. So if they got very worn - I guess they could shuck around a little.

The weakest bearing is the center bearing between the input shaft and output shaft. If bad, the front shaft will be loose that sticks out the front. Did you put a dial indicator on it?

The other two bearings are on the reverse counter shaft. If you drain the oil out and then remove the reverser filter- you can stick your hand in there, grab the shaft, and check it for play.

russdog · Aug 3, 2014

Thanks John for the info on the reverser. I really do not think the hammering is coming from it either. It sounds like it is forward in the bell housing. I am leaning towards the flywheel and bell housing contact. The info you gave earlier about pulling the starter and looking with a scope gave me an idea to pull the starter and putting some kind of marking compound on the flywheel and turn it over before pulling motor to look for culprit. The machine is a 1985 and I have had it since 1993 and have been the only one to run it and the reverser and drive train has always been tight. The knocking started with the isolator and replacing it leads me to believe it is in that area. Thanks for your input as it gives other areas to look. I will check the input shaft endplay when I remove the motor. Thanks, Ken

jd 350c knock

russdog

Member

Roger in Iowa

Well-known Member

JDemaris

Well-known Member

russdog

Member

russdog

Member

JDemaris

Well-known Member

russdog

Member

JDemaris

Well-known Member

russdog

Member

Similar threads