450c hot trans slipping

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Redroo63
MC crawler
MC crawler
Posts: 1
Joined: Tue Jan 18, 2022 5:44 pm

450c hot trans slipping

Post by Redroo63 » Fri Sep 12, 2025 3:04 am

Hi all
I've got a 450c that I've been battling with the transmission.
It was slipping in reverse gear after the oil warmed up.

I have adjusted the main clutch and the hlr clutches as per the manual and had the transmission shifting correctly. This seems to fix the slipping problem but after a few hours work the trans would slip again. It was like the nut would move on the hlr adjustment shaft. I've done the hlr adjustment procedure at least 10 times every time it works great for a few hours then slip.

Today I felt it was a bit sluggish in the forward gears so I connected the gauges and tested again.
All three clutches (hlr) drop pressure to about 50 psi when the brakes are applied when rotating the tracks off the ground.
Pressure in the hlr clutches are correct with no load on the trans and it shifts correctly.

I'm thinking the hlr trans has to come out for an inspection as I think reverse clutch is probably cooked.

Is there anything else I should look at before I tear it down.
Can you run the machine with the top plate of the trans removed?

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LeonardL
350 crawler
350 crawler
Posts: 916
Joined: Thu Oct 06, 2011 7:11 pm
Location: Missouri

Re: 450c hot trans slipping

Post by LeonardL » Mon Sep 15, 2025 12:38 pm

It does sound like you have an internal issue. Most likely wear and age will be what you will find. It's a long way into these things so be patient and take your time. You can run them with the top off of the transmission but I don't recommend it. No matter how hard you try to be careful they will sling oil out of the case and all over you and everything around you. Good luck and keep us posted on progress and or questions.
40 plus years working on JD 350s, 400Gs, 450s and other equipment both Ag and Construction.

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