much bigger problems now with 67 D5 - won't shift into gear

Hey everyone,

Well while trying to bring the tractor back to the shop to work on welding a nut to remove those super warn final drive bolts I had an issue with the dozer that caused me to shut it off and now it won't shift into gear or move.

While moving I started hearing this thumping kind of sound so I shut it down. Upon restart I still get the thumping noise and it will not shift into gear. I removed all the floor plates and checked the magnetic screener and saw what I have to assume is a normal amount of metal in there, but there is still definitely the thumping kind of sound I hear coming from the torque converter/transmission area in between the flexible coupler and the planetary gears. The linkage will not shift into any gear, the spring just forces it back into neutral and forcing it into the gear selection doesn't make any kind of attempted engagement sounds. Could this be a bad pump? Bad torque converter?

I'm still very new to this dozer and prior owner swears he never had any powertrain issues (of course). Bevel case has plenty of oil in it and it doesn't look bad, no leaks anywhere as a result of this incident that I can see. I did note that the magnetic screener filter housing was completely empty when I opened it to check it out, but given where it is in the system, perhaps this is designed to drain after shutdown and should be empty upon opening after shutdown? Or does this perhaps indicate a lack of pump flow? Any ideas on what to try and self diagnose. I have a field mechanic that says he can get here in a few days, but I'd love to try and see what I can figure out myself before paying $100 an hour and a $150 trip charge to this guy in case it is something I may be able to look into myself. This is a powershift tranny by the way on a 67 D5.

Thanks everyone!

You have no transmission pressure the neutral safety will keep it in neutral till it gets trans pressure check the drive coupling between the torque and trans. If that is good sounds like something in the convertor housing let loose and the trans pump is no longer driving

Ok so more info now leads me to believe something is way wrong with the flywheel output flange part of the flexible coupler attached to the flywheel. I have to assume you should not be able to spin the flex coupler and torque converter input flange independent of the flywheel, right? There isn't some kind of centrifugal connection between the flywheel and the flywheel flange of the flexible coupler, is there? I am able to spin the flex coupler freely and when I turn the engine over I see the flywheel turning but not the flex coupler or input shaft to the torque converter. Does anyone know how that flywheel flange connects to the flywheel? Is it just a bolt holding it on at the center? Or is it a hard shaft directly connected to it such that the flywheel flange is part of the flywheel output assembly? The manual on flex coupler removal isn't quite clear how it connects to the flywheel itself. It does mention on pg 25 of the D5 power train assembly and disassembly manual a part "3-Bolt, washer assembly, washer (assemble with concave side against washer assembly)" that looks like its pointing to the center of the flywheel output shaft. Is it possible this has sheared off? Is that the only connection of the flywheel flange to the flywheel? Seems like a weak point if so, but I also have no idea what I'm talking about but figured I should not be able to spin the flex coupler and transmission input shaft independent fo the flywheel. Anyone have any insight? Thanks so much!

edit: I think this would also explain the thumping sound I hear, as I also noticed that when the engine is actually started, the flex coupler is spinning much more slowly than the engine rpms, which I have to assume is also not normal and the broken connection there is what is causing the thumping sound.

Here is the page I'm referring to:

https://ch-part.com/i.caterpillar/reg008880007/

Yes you tore out the rubber pucks have to dissemble and remove old pucks

The rubber pucks are 100% intact. I’m saying the flywheel flange (or the engine facing surface the pucks are connected to) spins freely of the flywheel shaft.

Well the flange must of come loose from the flywheel still have to take it down to see what is going on

Seems you have lost (worn out) the splines in the coupling and flywheel stub shaft/flange.

Old Magnet said:

Seems you have lost (worn out) the splines in the coupling and flywheel stub shaft/flange.

Click to expand...

thanks, this is what I was trying to figure out. Is there some kind of splined shaft in there connecting the flywheel to this flywheel flange of the flex coupler. Do you happen to know where I would find any more info on this flywheel shaft? Thanks so much. The diagram of the flex coupler depicts a shaft of some kind but doesn't name it as a part, so maybe the engine manual (which I don't have...)?

I got the pan off and took a good look at it, there is definitely free play in the flywheel flange shaft and now I am working out how to get the bolts holding the pucks together off of a spinning shaft. Don't have rebar or flat bar small enough to fit through the center openings between the pucks to be able to brace it....

You need to consult a parts book. Shaft is part of flywheel flange assembly # 85506. Need a tractor s/n to be sure.

Old Magnet said:

You need to consult a parts book. Shaft is part of flywheel flange assembly # 85506. Need a tractor s/n to be sure.

Click to expand...

I have been pouring over everything I can find about this coupler in both the service manual and the parts book I have but can find out about everything but this shaft, both the engine related sources and flex coupler sources seem to just assume it. I will look up that parts number. Serial 96J2655 Thank you so very much!

looks like a 8s0510 and a 8s0506 you need to tear it down before you order parts though

can get the 8S0506 for around $200.00 after market the8S0510 is backordered or you can find used

Contact Information
AIC Replacement Parts
Williamston, Michigan
Phone: (888) 984-3053
Contact: Robert Perry

Looks like the coupling changed at s/n 96J2655-up which I show as being a 1971 model.
Coupling changes to a 12P1035 assembly with the drive flange a 2P1012.
Could be your unit is on the fence with the former biscuit type coupling.

8S0510 CATERPILLAR

For Sale Price: Call

Available: 6
Contact Information
AMERICAN CRANE TRACTOR PARTS
Kansas City, Kansas
Phone: (800) 999-8538
Contact: Dave Sellinger
Email
AMERICAN CRANE TRACTOR PARTS

If your having that much wear the torque converter input splines are probably well worn also.
Be prepared to run a thorough alignment check of the coupling.
Seems all the parts are available after market with quite a range of pricing.
My bad 85506 is actually 8S0506.

So here is the flange. You can see in the second it has completed spun out of its connection to the inner flange plate. Looks like there are two flanges connected by that center bolt you can see in the pic. It currently just flops around in there. Here are a couple pics of what I am dealing with. This part doesn't look like the pic you posted. Looks like its double disc sandwiched together with a shaft. As far as the year, I have no idea I just went off of what I was told by the guy that sold it but 96J2655 is the serial. I guess I need to pull the flywheel housing cover and remove the bolts on the "inner" disc that I assume is bolted directed to the flywheel. But I think I'm still searching for part numbers, but I will read the posts above more clearly and see if I can find what I need. Thanks everyone!!!!

After looking at this for a bit Im gonna say this has been fixed before, that looks like a weld bead going around the failure point. Wish the guy would have found a replacement part.... maybe he was having as much trouble as I am! Will know more when I finally get the entire thing out, was just trying to get ahead of trying to source parts as I want this thing back up and running and crushing cedar trees asap!

so based on what I understand so far, 8S0510 flange is the one that the part of the flex coupler, but it appears that either I need that one AND what ever that flange bolts to, or I just need the other one that this one bolts to. That's the piece that Ive been having so much trouble trying to identity. Its the piece that actually bolts to the flywheel and accepts the 8S0510 flange, which is the grey flange disc you can still see attached to the flywheel in the pic.

Dave Neubert said:

View attachment 228150

Click to expand...

OK THANK YOU I finally used my brain and figured out you answered my questions above. YES, I believe I need at a minimum the 8S0506 and possibly the other one. Im hoping I just need the 506 as its much cheaper than the other one. THANK YOU SO VERY MUCH TO EVERYONE and a special thank you to Dave.


As a side note, thats a pretty small chunk of metal to support all the torque that 3306 can muster. Interesting design choice, which doesn't really surprise me it broke now that I see how it all goes together.