1973 JD450BA

[Anthony Rivieccio]

Hi
Based on http://www.jdcrawlers.com/messageboard/ ... php?t=2415 I think I have a 1973 JD450B


I'm using a 1987 TM1033 technical manual and I can't find this component (in the red rectangle) anywhere in the TM

Does anyone know what this arm with rod attached does?
The other end of the rod connects to another arm seemingly in the steering clutch case?

Is there a better manual to use?




and what is this disconnected wire near this switch?

[Jim B]

Welcome to the Boards.

I don't have a 450B, so might be off on these answers.

The switch and disconnected wire appear to be the safety neutral start switch and wiring, which has been disconnected. If your 450B will start without being in neutral that is why, someone has jury-rigged the starting circuit. Best to get it repaired.

I am guessing the rod you are looking at is a brake rod. Move the brake pedal while watching the rod. Does the rod move when you push the pedal? The foot brake pedal linkages work both brakes together, separate from how the steering levers operate the brakes individually for steering.

[Anthony Rivieccio]

Thank You Jim !
I'll make note of all of that and look into it !

[Anthony Rivieccio]

Hello again !

I had a chance to look into this and yes to both. Thanks to Jim! but i did not connect the neutral safety switch just yet. still looking into understanding the issues w this newly acquired machine. it seems that someone shortened the left side brake rod (pictured) possibly bc the band on that side was hanging and wore out excessively. i did not confirm that yet.

while manual box is neutral between 2 n 3, and HLR in neutral 800 RPM pressure is about 185. in reverse it bounces back to 150 in 1.4 seconds from a 60 lb drop. in H and L it bounces back to 180 in 1.2 sec. from a 40 lb drop. , H and L drive forward and seem to pull well when throttling up. R attempts to move but gives 6 or 7 inches at best. 1600 RPM all pressures and timings are a little higher and a little faster.

the nut on the rod inside the left bell housing port is about one thread off the end of the threaded stud rod. cranking it out further yet one thread makes the shift much faster and drop less without changing the max pressures. cranking it in 5 threads makes the shift much slower and drop a lot of pressure during the shift and going to reverse the pressure is very long to recover and doesn't even reach the pressure it reached with the nut backed off. but again cranking the nut no real difference on max pressures (other than in reverse) on all testing as though all that rod does is regulate the output from an accumulator.
BTW fluid is clean and reportedly new w a cleaned filter by previous owner who gave up on making reverse work. i do not think he checked pressure or adjusted anything though.

??could an issue exist with the reverse passage bc of a cooling circuit issue? the trans cover never gets warmer than 110 deg F really.

other issue when i test drove it before buying it i also thought the clutch pedal felt fine but when i picked it up the pedal had one firm throw and has been much easier to depress ever since. In looking through the left side port at the top of the bellhousing, one can see a rusty (now soaked several times by spraying deep creep) shaft spline and pressure plate forks (in the depressed position). but yet the machine seems to pull hard in all gears both high and low. i drove up the trailer loading ramp in 1st H without any slippage that i can tell.

I tried the adjustment procedure again and it seems that optimal is w the nut about 3/4 of a thread off the end of the adjusting rod. any more than that depressing the clutch would have no 5lb rise in pressure at 1/2 to 3/4" travel before dumping the pressure on furthering the throw. And cranking it in only slows the shift and lowers pressure during the shift.

i still have that pressure plate anomaly
why would the pressure plate tangs be so far away from the throw out bearing angled inward slightly as though they are locked in the depressed position?

if not the valving this issue is sounding like i have to either try sliding the motor forward and or pull it. good luck w that if the spline is rusted to the clutch hub.

is it a free floating input shaft ? the kind that just slides out ? if so the motor is going to have to move forward quite a bit before being free.

advice would be appreciated

we have a pdf that is not as detailed on the disassembly as i would think it should be but maybe i could use it to study the fluid flow to detect whether there might be an issue. anyone who knows these fluid circuits could help. my pdf seems to mention a filter as though it is a main filter and another screen like near the valving. any experience in checking all screens would help. the previous owner described a screen he cleaned along w the fluid change. but by the description of that the new fluid in there will have to be drained to the half way mark.

Anything at all which may be the cause of low pressure reverse only that can be accessed wo removing the engine would be Good to know.