JD 450 HLR transmission pressure adjustment and theory 

yeah,....you are totally not a bot,....because it is obvious all chicks are into dozers..... 1984 in effect

So cool that its all mechanical. Deere was really building nice stuff back in the day.

Glad it was helpful. I like your idea on a buyers guide, I think ill put something together about these. Something I wish I watched before I bought this one.

Yup of course, as well as the suction screen on the bottom of the transmission

@@spankranchgarage They good dozers, I bought my 450b in 1981, it's a 74 model, I've changed the clutch about 3 times and the steering clutches about 3 times, I still have it, still running good.

@@dDayye Love to hear that. I may have this one for the rest of my life!

Looks like a penny is about .06" thick. I used standard 303 tractor fluid from Tractor Supply, made by VP. I think temperature plays a big factor here as it seems to affect the pressure greatly. Id be scared to know what this pressure looks like on a 0 degree morning. Mine will shift gears (1-4) at an idle only if I shift quickly. If I go slow the drivetrain will pick up speed between gears then it will grind. If I get stuck between gears I just shut off the engine and put it back in the gear I want. Its not ideal but in real life I am not sure I will be changing gears that often. I am new to running a dozer and will probably stick to 1st gear unless I am heading long distances.

I think when I changed mine a few years back I used Walmart's SuperTech universal transmission/hydraulic fluid. Temperature definitely makes a big difference (you can look at viscosity curves and see that clearly). I can get over 200 psi when the oil is cool (90 degrees F), but it drops significantly when you get up to the range they recommend for setting pressure. The viscosity on these type 303 fluids is about 9 cSt at 100 degrees C (roughly equivalent to a straight SAE 30 oil). Although I've only got probably 200 hours on the transmission oil, the overheating I was getting before due to the pressure valve being essentially closed when the oil got warm, therefore not providing any filtering or cooling, may have damaged the oil. I'm trying to find a thicker oil to use to compensate for the pump wear - looks like an option might be an oil meeting the Cat TO-4 50 spec, which would have a viscosity of about 18 cSt at 100 degrees C (SAE 50 oil). Any heavy pushing I do in 1st gear, and low range, and will go to high range for moderate loads. If I'm trying to do some smoothing with light loads of dirt, I'll use 2nd and go between low and high range as appropriate for the load. I only use 3rd and 4th when moving relatively long distances to get from one place on my farm to another. @@spankranchgarage

@@VRM-uu3si I like what you are thinking with the CAT fluid. More viscosity will hopefully enable better pump pressure and more oil making it to the cooler. You might have to mess with the needle valve to keep the shift speed quick to minimize clutch slip. Just curious do you see the same pressures in H L and R? If only 1 or 2 speeds shows lower pressure, its possible there is an internal leak that can be fixed without too much disassembly, just by removing the top cover.

As I recall, my pressure was about the same in all positions of the HLR, but I'll check it again and get back to you in a week or so. Unfortunately, I think if you see a big difference depending on which position you select, then it is a sign of internal leakage. I went back and watched around 14-15 minutes into the video and all your ranges looked to be around 160 psi at that point - I didn't see enough variation to worry about. I think clutch activation pressure is fed through the front cover of the transmission with the HLR valve determining which passage the pressure is fed to. This goes into the clutch shaft through holes cross-drilled in the shaft to oil passages drilled along the axis of the shaft. Seal rings (piston rings in JD part catalogue) shown in TM Section 50, Group 15, Figure 33, part 18, seal the passage way between the front cover and holes at various points along the clutch shaft. This area would be one possible source of a leak. On each of the clutches (H, L, and R), there is an inner and outer seal within the clutch drum, which is the other possible source for internal leaks. This is shown in the TM Section 50, Group 15, Figure 12. It looks to me like you have to pull the engine and partially disassemble the transmission in order to pull the clutch packs out of the transmission, which is what would be required to address either one of these two possible internal leaks. This seems like one you don't worry about until it blows out completely, or gets so bad it slips in that range selection. @@spankranchgarage

I finally got around to checking my HLR pressure in all positions - I got the same pressure in neutral, H, L, and R, that being where I set it at about 140 psi as I explained in another reply due to a weak pump I think. I'm hoping to do some work with it in the next few days to see how hot the transmission fluid gets. If it stays below 220 degrees, and hopefully below 180 degrees, then it would seem I am getting the cooling I need. If I get slippage I'll look more into the thicker fluid and setting the pressure to the recommended 170-180 psi. @@spankranchgarage

I personally would look into leak checking each clutch actuation circuit. I haven't gotten into one of these transmissions far enough to know what to tell you. Variation between low reverse and high is a clue. You have some shared circuitry and some independent circuitry/seals. studying the fluid flow diagrams you might be able to come up with a few sources where it would leak and cause what you are seeing.

Thanks! I use the tractor supply J20A fluid. Its reasonably priced. May not be the best stuff out there but its better than the water oil mix that was in there for all these years. www.tractorsupply.com/tsc/product/vp-racing-lubricants-ultra-j20a-plus-utility-tractor-fluid-5-gal-vp2040114

I agree well tomorrow will be in mechanic mold buddy I am from Louisiana wby ?

In this video I was running it with the 4 speed box in neutral and the HLR in gear. You would think it shouldn't generate much heat... Fast forward to a few months later I cleaned the trans fluid cooler really good while I had the engine out. When working the dozer hard the trans still gets pretty warm but nothing I cant hold my hand on. No change in shift quality or speed so ill leave it be for now. Thanks for the comment!

By "Free-play" I mean the distance from pedal all the way up, to where the throwout bearing contacts the engine clutch fingers. In that range of motion the clutch pedal is activation the HLR side of the transmission. The remaining pedal travel is disengaging the mechanical clutch like a regular car or tractor.

No problem 👍

Its taken off because I have the floor boards out. But I do have it and will certainly be reinstalling it

Hygard

You can download it online. It cost me almost 50 dollars but we’ll worth it

The service manual has what your looking for.