1977 JD 450c Loader has no power in reverse

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Sabaro
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Re: 1977 JD 450c Loader has no power in reverse

Post by Sabaro » Sun Aug 05, 2018 11:47 pm

I checked the clutch today and found free play at 4-1/4" of travel. I adjusted the clutch to 3-3/4" of travel and the trans pressure went up slightly to 174psi. prior to adjusting the clutch the pressure was at 169psi. The rpm's were set to 1500rpm and the transmission pressures for H/L/R were as follow:
N=174psi
R=Dropped to 80psi then climbed back to 156psi
H=Dropped to 80psi then climbed back to 170psi
L=Dropped to 80psi then climbed back to 165psi

Next I attempted to adjust the transmission pressure up to 180psi which I did with 4 full turns clockwise of the pressure adjuster under the rubber plug. I next checked the H/L/R pressures at 1500rpm and found:
N=180psi
R/H/L=all 3 were at 40psi or lower.
This worried me so I reversed (counter clockwise) the pressure adjustment adjuster 4.25 turns and that seemed to have the highest consistent pressure for N/H/L/R.
N=165psi
H/L/R=160psi

The next test was to put the transmission into gear (1st gear) and function test the H/L/R. The tractor was is back to having power in Reverse and Low range. The transmission was a little punchy between L and R. I started lowering the transmission pressure a quarter turn at a time trying to soften the shuttle between L and R. I got down to 80psi and saw no change in transmission punchiness, so I raised it back up to 165psi. I was able to soften the transmission by increasing the clutch free play to 4" of travel.

Now I'm just plain confused as to why my settings are so much different than the write up. The "penny" shim still has me scratching my head, because I'm not sure where to put it. My pressure adjustment was made by just turning the nut. can you explain where the shim goes? Also does the above sound ok to you guys? did I do something wrong?

Thanks Sabaro

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Re: 1977 JD 450c Loader has no power in reverse

Post by DrLoch » Mon Aug 06, 2018 7:01 am

Do not soften the shifts with the pressure adjustment You adjust the speed shift with the needle valve accessed through the side of the transmission, not by lower the clutch pressure. That pressure is needed to keep the clutches clamped up, no different than the automatic transmission in you car. If the pressure is low clutches slip and you burn the friction material odd now you have an expensive paper weight. If the F - R or R - F shift is too aggressive if you, you 2 options, 1) adjust the needle valve to slow it down accessed through the side of the transmission and not easy to get at or do what I do, press down on the clutch pedal until you have hydraulic release shift and go the other way.

Do you have a manual? The shims go under the pressure regulating cap, look at System testing 70 pg 25-7. Access to the shims is accomplished by removing the right rubber plug the pressure control valve nut is under it. ..Pull the pressure control valve nut , again use a greased socket so it stays with the socket, carefully remove the plug and watch for shims in the plug and on top of the spring.
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Re: 1977 JD 450c Loader has no power in reverse

Post by psprague » Mon Aug 06, 2018 7:39 am

Sorry, the proper terminology from my service manual is Cushioned and Rapid shifts. I should know better than changing the jargon.

For H -> L or L -> H, the shift is as rapid as possible. If it's pushing hard (and going the same direction!), you don't want hesitation.

From R - > H/L or H/L-> R, a rapid shift will literally give you whiplash so there is some valving that cushions (or slow down the re-engagement) the shift.

Adjustment of the softness of the cushioned shift is accomplished with a needle valve adjustment.

The tubes I was talking about transfer the oil from the shift valve to the clutch packs. While I've not experienced this directly, there are oil ring seals on these tubes which deteriorate. The idea is a leak at an O ring would give different ending pressure readings after a shift since the leakage is in the individual clutching circuits.




The JD parts catalog is awesome, if you haven't bookmarked it.

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JD 450c forestry, JD 440A cable skidder

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Sabaro
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Re: 1977 JD 450c Loader has no power in reverse

Post by Sabaro » Tue Aug 07, 2018 11:42 pm

DrLoch & psprague, Thank you both for sticking with me.
psprague I totally understand your shifting now. Thanks for the clarification.
DrLoch, I totally blew it. I removed the rubber plug on top/left side of clutch housing and turned the nut in the hole thinking it was the pressure adjustment. I went counter clockwise 4 turns and got the pressure up to 180psi with RPM's at 1500, 4 speed in Neutral, and H/L/R in N. I noticed the PSI drop to 40psi or less in H/L/R. Is that because I was adjusting the "Clutch Lubricating Bypass". I will take the right floor board off this weekend and look for transmission pressure adjustment. First I need to adjust clutch back to 3-3/4" of travel. On the top of the transmission clutch housing there is a rubber plug same side as the clutch. Is this the "Clutch Lubricating Bypass"? If so I turned that nut, so is there an adjustment for it. Is the transmission pressure adjustment on the top right side of the clutch housing, under the right floor board? Is there an worries when removing the transmission pressure adjustment cap to add pennies? My repair manual is on my computer and I drives me nuts trying to navigate through it. I like hard copies much better, I should take it to staples and print it off.

Thanks again
Sabaro

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Re: 1977 JD 450c Loader has no power in reverse

Post by DrLoch » Wed Aug 08, 2018 6:54 am

You need to redo the clutch valve adjustment procedure correctly. If you seen 180 PSI you should not have to add anymore shims. Do yourself a favor and print off all the pertinent information that you need to do this adjustment procedure correctly, all the information has been provided in this post.

You were probably had it correct at one time and continued to play with it until you got it out of adjustment again.
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Re: 1977 JD 450c Loader has no power in reverse

Post by Sabaro » Sat Aug 25, 2018 10:40 pm

Update....

I'm still having issues, with power in reverse. Here's what I've done thus far:

1) I adjusted the clutch free-travel" from 4-1/4" to 3-3/4".

2) Adjusted the H/L/R linkage stop nut in until the clutch peddle just starts to lift off of the stop, then I backed the stop nut off 5 full turns. Next I placed the transmission 1-4 in Neutral (between 3-4) and the H/L/R in neutral. My manual says to start the engine and set it to a slow idle!?!? What RPM is a slow Idle? next the manual sys to turn the stop nut clockwise until the pressure starts to drop then continue one more tune clockwise. Then it say to press the clutch in 1/2" to 3/4" and pressure should go up approx. 5psi. Here is my problem, first off the pressure never starts to drop while turning the stop clockwise, and my pressure drops every time I push the clutch in. I've tried turning the stop nut out the 5 turns then with very small adjustments up to 4 full turns in both directions and never does my pressure drop off. While doing this my pressure as low so I added 1 penny and tried same adjustment of the stop nut again with same results. 1 penny got me to 160ish psi with both shifters in neutral so added a second penny and got the pressure up to 180-185 but still same results. It seams like the stop nut is making the shifter either hard or soft depending on weather or not I'm in the clockwise or counter clock wise direction. I read that if pressure doesn't start to drop off and or if the pressure doesn't rise 5psi with 1/2" to 3/4" of clutch travel then the linkage could be froze. I have noticed that when the tractor wont back up if I press the clutch peddle in a touch then pressure builds and tractor backs up. What the heck is going on!!!!!!

I had to stop today and just ask what has changed between now and when the tractor worked perfectly? We had a blown pressure house in the left final that prevent the tractor from turning when the right friction was pulled approx. 5 years ago. I disassembled the cockpit and removed the final lids to replace both pressure hoses (1 per side), then reassembled everything. I didn't adjust anything except the steering brakes. So why is this machine now needing major adjustments from the transmission and clutch. In case I haven't said this we only use the clutch to shift transmission 1-4 at idle and that's it. Its hardly ever used. Is there something I'm missing? I hate to throw in the towel on the ole girl but damn!

Thanks again Sabaro

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Re: 1977 JD 450c Loader has no power in reverse

Post by Snookdoc » Sat Dec 01, 2018 7:14 pm

I have a 1981 450c having the same issue. Did you ever figure out what was wrong?

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Re: 1977 JD 450c Loader has no power in reverse

Post by psprague » Mon Dec 03, 2018 12:47 pm

Hi Snookdoc, have you performed the clutch adjustment procedure?
JD 450c forestry, JD 440A cable skidder

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Re: 1977 JD 450c Loader has no power in reverse

Post by Snookdoc » Sun Dec 16, 2018 12:02 pm

Sorry to take so long to get back to you. I have about 2 1/2 of free play

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Re: 1977 JD 450c Loader has no power in reverse

Post by Snookdoc » Sun Dec 16, 2018 12:06 pm

When I checked the pressure at idle it's only at 130 psl

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Re: 1977 JD 450c Loader has no power in reverse

Post by Snookdoc » Sun Dec 16, 2018 1:14 pm

To psprague
in my original post I put in 450c its really a 1981 455 crawler with a operators cab, made in Germany. I was told it uses the same parts as a 450c. In the 455 crawler loader manual it says to adjust free play to 60mm (2.35 inches.)so that is where I adjusted it too. I locked the brake pedal down and used it as a reference to measure the clutch free play. not sure if that is the proper way to measure it.

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Re: 1977 JD 450c Loader has no power in reverse

Post by Jim B » Mon Dec 17, 2018 10:00 am

Hello Snookdoc,

What is your general location, if I may ask? Hopefully psprague will have more info for you but in the meantime, a bit on the machine, please. Apparently, Germany was using the 455 designation before the US started using it. I say that as at first any info I found doesn’t show the 455 series starting until 1983 with the 455D, before that it shows only 450C crawler loaders in 1981. I took a look on the JD technical publications site and found the straight 455 designation for Mannheim 455 manuals there. (English versions: PC4178, TM4392, OML35360)

I didn’t understand your using the brake pedal as reference, until in looking at the preview of the operator’s manual (OML35360) I see it appears you have pedal steering, so the clutch and brake pedals are side by side between the steering pedals. Is that correct? Clutch free travel is the travel of the pedal from its “top” position to the point where the throwout bearing is touching the pressure plate fingers. Is that the measurement you took? There should be more to the clutch adjusting procedure than just the free travel in the manual, as was discussed in the posts here by others. Did you find that full procedure in your technical manual and did you do the full procedure step by step? As seen by the free play specified in your manual compared to the other posts here, there may well be some other differences in specifications in your manual from what most here have available to reference.

Best regards, Jim

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Re: 1977 JD 450c Loader has no power in reverse

Post by Snookdoc » Mon Dec 17, 2018 8:01 pm

Hi Jim, I am in east Tennessee, The loader is a 1981 455 with foot pedals. The manual I have is TM4392. It says to unhook clutch fork from lever and loosen hex nut. adjust free travel to specified 60mm (2.35" )and tighten hex nut. NOTE before adjusting clutch pedal make sure all pedals are in alignment, if necessary realign pedals. I adjusted the clutch pedal to where it has 2.35" of travel. I will go back out tomorrow and see if I can feel when it touches the through out bearing. and try adjusting from there. Thanks mike

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Re: 1977 JD 450c Loader has no power in reverse

Post by Snookdoc » Mon Dec 17, 2018 8:41 pm

4 pedals left, clutch , brake, and right.

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Re: 1977 JD 450c Loader has no power in reverse

Post by Jim B » Mon Dec 17, 2018 9:15 pm

Does it have the same transmission as in the other posts here? (4 speed gearbox with a range selector, H/L/R) I tried to access the PC4178 parts catalog but at least as yet it doesn't come up, so can't cross reference any parts to US 450's. In your technical manual after it tells you about adjusting the free travel does it go into the same H/L/R adjustments and pressure gauge readings as were described in the earlier posts here? If it does, you need to run that whole sequence and see what the results are.

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