IH 300 U Gears 4 and 5 Not Engaging

Paddy K

New User
I have an IH 300 Utility (1955). After sitting in a shed for 15 years. I have brought it back to life which basically involved cleaning the points and replacing some old wiring. I have also rebuilt the hydraulics in order for them to stop leaking with new rings and gaskets. I drained and replaced all fluids on the tractor, the trans fluid was milky but there were only a few small filings found in the rearmost drain plug. I don't think we ever changed out the transmission oil in the past. My next challenge is the following:

The tractor works great, except I cannot put it in the road gears 4 and 5. All other gears (R, 1, 2, 3) work fine, including with the torque amplifier. Independent PTO also works if this is relevant. These gears used to work 15 years ago, although they weren't used too much. There was no catastrophic incident where those gears suddenly stopped working. I don't hear anything grinding inside the transmission. The shifter will move all the way to the right but it will not engage up/down into the gears (I am fully stopped and wait for the gears to stop spinning before trying 4 and 5, clutch pedal all the way down). I had hoped the new trans oil would work into those gears after a bit and they might start working, but this hasn't happened and I've been running it every day for two weeks. Rather than force it and bust the forks, I want to ask how I should proceed. I plan to take the shifter off the transmission body and try to free up the leftmost rail (shifter to the right means rail & fork to the left) which I think must be rusted stuck. I guess I would just try to free it up with penetrating oil and a large screw driver. Do you think this is what's wrong? Am I going to have to take apart the hydraulic reservoir again and go deeper into the transmission? Will I need to drain the transmission again? I have the I and T shop service manual for models 300 through W 450 D which does describe the transmission in general but doesn't show how the forks interact with the gears in the transmission.

I have a diagram but I am a new poster and I guess I cannot upload that yet (I will soon). Any advice would be greatly appreciated!
 
If the rail won't move after shift lever is removed with a bar it could be the rail or springs and balls stuck or the 4th and 5th slider gear rusted on splines. On a row crop without a belt pulley gear box the opening cover can be removed and look at the slider gear and forward end of fork. But a utility is more involved.
 

Okay, that is pretty much what I figured. It looks like if I cant get it by removing the shifter lever, then I need to remove a large plate under the seat as well, which involves draining the hydraulics, removing the hydraulic reservoir lid (under the seat) and then a big plate beneath that as well. At that point I will definitely see the problem although I might ruin a very large gasket. I wish I could post the diagram I have, cannot post a link either yet. It can be seen by putting " (232) - CHASSIS, GEAR SHIFT MECHANISM, REAR FRAME AND HYDRAULIC RESERVOIR COVERS Case " in google images. If I removed plate (15) I would see everything but also might be up the creek.

I will try the lever first.
 
Look at the base of the shifter,you will find 6 bolts,that plate will lift off. There are springs and
detent balls. Watch out for them they have to go back in. I think you will find a rail that will not
move. I have seen this before on 300s,water runs down the shifter,into the housing and into the
spring detents and the rails stick. Easy fix,the hard part is working the rail and keep your favorite
rust Blaster sprayed around, and work the rail with a pry bar.
 

We'll I have tried that now -- didn't work. The rail was a little bit rusty but not stuck in place. The leftmost rail has two balls in it and the rest have only one (fun fact), one was a bit rusty but nothing major. Anyhow, it didn't work to clean and grease those all up. The rail can move a bit but still wont go into gears 4 & 5. Now I guess I've found it must be the sliding gear for 4 & 5! I plan to take off the bigger plate (and all of the other stuff above it), at least I'll get to know for sure what's going on in there.

I wonder if I can just lift the whole hydraulic reservoir and levers up with it. What could go possibly wrong? :shock:
 
(quoted from post at 20:39:46 12/14/20) Look at the base of the shifter,you will find 6 bolts,that plate will lift off. There are springs and
detent balls. Watch out for them they have to go back in. I think you will find a rail that will not
move. I have seen this before on 300s,water runs down the shifter,into the housing and into the
spring detents and the rails stick. Easy fix,the hard part is working the rail and keep your favorite
rust Blaster sprayed around, and work the rail with a pry bar.

Yep. I did as you said and it still didn't work... Until yesterday!! I was just working with it and tried the 4, 5 gears! Eurika! It just went into 4th gear. Then I tried 5th and it worked as well. I figure those sliding gears were a bit rusted to the spline after sitting so long, I understand that spline is above the oil level. Just getting the oil splashing around in there, and the gears moving did it. Now I don't need to take the trans cover off!

Hopefully this helps anyone facing this issue in the future:

1. Take off the stick and clean and grease the rails springs balls etc. and make sure they are not rusted in place.

2. Make sure the trans has good fluid in it to level.

3. Drive the tractor all around, up and down hills etc. and get it nice and warm.

4. Periodically check if stuck gears work.

Note, I never tried to force those gears in for fear of breaking the fork, I'm glad I didn't.
 

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