‘86 8B with powershift. Replaced u-joints in driveline (parts are NLA for these machines so took awhile to find the right guy that knew mechanics style u-joints to source me the right ones). While machine was down, changed fluids and cleaned replaced filters. Very little of anything on magnets. Two months before I got the parts and the time, between planting, spraying and baling hay, get the u joints in yesterday and dozer will not move. Fluid levels all good, no leaks. Trans pressure gauge goes into the green band (no pressure reading) and driveshaft spinning, put in any gear and tracks snug up and driveshaft stops, pressure gauge decays well into the red. Back into neutral and pressure pretty much hangs out. Can work the heck outta the shifter I a big circle several times and return to neutral position and gauge will get back to the green, put in gear, same thing happens. Once I got it to get back into the green after leaving it in gear at WOT for about 3 minutes but it never offered to move. Can raise machine with blade and tracks travel when it pivots on the rear, so not frozen, plus engine RPM never changes so it’s not loading up. I am ignorant to the intracacies of how this one works, and there is no such thing as dealer support. New holland construction owns it now but I have yet to find one that supports it. I have the operator and maintenance manual, just not a tech manual. All this Italian stuff is metric, and I doubt there’s a pump on earth to fit this machine. Just waiting on the day to come when I can’t keep it going, shame because it’s good good UC and engine is strong at 7500 hours. Converter, charge pump? I’m at a loss. About 4 years ago I did a full fluid change and I remember saying I wouldn’t ever do it again because it didn’t move after. Took a couple days of fiddling with it off and on before it finally took off one day. The thing would break your neck if you didn’t hit the decel pedal when going forward to reverse, find it hard to believe it just went to crap sitting for two months. It usually sits much longer than that, typically November to April.
Green band in neutral, red in gear with no spinning of driveshaft
Converter is not charging for some reason, this is nothing Allis except in name. Need to get into how the charge pump(Flywheel Driven) delivers oil to charge the torque converter. It is possible a system vent is slow or choked not allowing the converter to load.
Put air to the reservoir today, charged up and took off. Blew a hydraulic hose on one of the blade circuits almost instantly so couldn’t test if it would hold prime. Looks like worst case, the charge pump is going bad, but maybe I’ve just got a suction leak. Hope it’s not the pump, as there are no parts available, but this pump doesn’t look original so maybe it’s a common part, I can’t get to any numbers yet.
Sounds like a suction leak to me. The o ring under the filter cover has caused problems on our 14C in the past. That looks like it above the pump. There are still parts available for these tractors, just not in the US it seems.
That o-ring can be a tricky son of a gun to get in place correctly. I will pull the cover and check again. Yes, it's above the pump. Do you have any contact info you could share for parts sources? Obviously anything large or heavy would probably be very costly to ship, but when that's the only option vs retire a good machine, sometimes you have to just deal with it.
There might be a separate transmission filter with a similar o ring that would also need checking. We are fortunate to have two businesses here that import parts from Italy fortnightly. https://tractorspareparts.com.au/ https://gwtractors.com.au/ Most of the parts seem to be sourced from this outfit. http://www.ghinassi.com/
Awesome info Queenslander, I really appreciate it!
I too have a Fiat 8B. I have played hob finding parts. John at https://tractorspareparts.com.au/ has responded to email about getting undercarriage parts. Thank you OP and Queenslander. We are in central Ky ihmanky.