350 strait reverser ??

[350strait]

I have a 350 strait (no letters after it) that the reverser is not getting to the correct operating pressure of 120-130 PSI. Cold (90 degrees) it hits 100-105 and hot it hits 95-100, the maintenance manual says to adjust the shims under the 120 LB spring to raise or lower. Question is, more shims equals more pressure or less pressure? Whats happening is the fluid is getting hot enough that the clutches are not staying engaged, or the pressure is not high enough to keep them engaged and the dozer won't move till the fluid cools down. I found this out while using it and all of a sudden my right foot got hot from the fluid overflowing through the dip stick tube.

Need help so I can start a new job. I'm going out to drop the 120 LB spring out and see if increasing shims will increase pressure, I tried last night, added around .020 and it did not seem to help any so I'm going to see what .040 or .050 will do, only bad is, its hot, and I know that there will be fluid loss.

[350strait]

Well , adding shim thickness adds pressure. Added about 1/4 inch to the 120 LB side and got to 110-120 LBS, good enough. However when I pulled the 95 LB spring to add to it (was only getting 75-80 LBS) not only did the spring and shims come out, but the piece above it came out too, this did not happen with the 120 LB spring. Only the spring came out and getting the bolt started to screw it back in was a pain because the spring was hanging out of the housing so I had to compress the assembly to get the bolt started in. Is it possible that the piece above the spring is hung-up in the housing causing me to have low pressure.

[Lavoy]

You wouldn't think so, what would jam it in there, can't be corrosion.
Lavoy

[350strait]

Lavoy

I would not think that that particular valve or plug or whatever would stick in place either, however I took the dozer out this morning to move some ground up road base and now the reverser pump has blown a seal, that seal has about 3 hours on it so now I'm thinking time to see why the shaft is moving enough to cause the seal to give. Off to pull the engine and I hate to think the reverser too in 100 degree heat in the back yard (no shop or shade) gotta love it.

[Lavoy]

If the input shaft is moving up, down or more than a few thousandths in and out, sounds like a bearing went bad.
Lavoy

[350strait]

Can I replace the bearing without having to pull reverser?

[350strait]

Lavoy
Never mind on previous question. I just looked at my manual, and it looks like the reverser has to come out of the dozer to get to the back bearing on the spider shaft because the reverser controls come off first to remove the oil tubes, then remove the spider shaft with the clutch assembly. Pain in the rear.

[gregjo1948]

Did the seal fail due to shaft movement or fluid pressure? If the pump seal failed, you can replace it by pulling the engine and leave the reverser. If you need to replace the spider shaft bearing and race, I believe you can pull the front cover of the reverser to access them, without pulling the entire reverser housing.

[350strait]

Don't know why seal failed yet, but, I think the last time I replaced it the shaft may have moved. I hope to pull the engine today and see if the shaft moves for sure and I may try pulling the front cover and see if I can get to both bearings I see on the parts breakdown on the JD parts site. Going to see if I can borrow a forklift this morning. Will keep you updated.

[Lavoy]

The problem will be the end play in the bearings. That is adjusted from the rear of the reverser.
Lavoy

[gregjo1948]

THERE'S 2 BEARINGS ON THE CLUTCH SHAFT AND ONE ON THE SPIDER SHAFT. ARE THEY ALL ADJUSTED WITH THE SHIMS ON THE QUILL AT THE REAR? If SO, HOW IS THE AMOUNT OF SHIMS DETERMINED?

[350strait]

Well the forklift did not work, gravel I'm parked on was to loose. I did get the engine away from the reverser and the shaft is loose. According to my manual the bearings are shimmed from the back as Lavoy said. Takes a dial indicator .002-.004 movement back and forth. So now I try to figure out how to get the reverser out while balancing the engine on the front of the dozer. I may try to get the engine completely away from the dozer before trying to get to the reverser, the book calls for removing the control and gauge cowl above the reverser so I have to figure out getting it out and off too. I'll keep you informed.

[Lavoy]

Dial indicator is best if not only way to accurately measure end play. Been a few years since I did it on a reverser, but trans is same concept.
Lavoy

[350strait]

Finally got the reverser unbolted and out. Whoever decided to use 1 5/16 inch head bolts on the right side should have to do remove and replace this thing, it took an average of an hour a bolt, and there are 11 bolts that need to be removed just for the reverser. Used a friends tractor to get the engine and reverser out and over the blade, and on the ground. Now the fun starts, disassemble the reverser and look at the bearings to see why they are loose. I just hope its something easy and cheep.

[350strait]

Found the problem, seems the bearing on the front of the shaft that has the clutches and pistons either locked up first or the shaft sheared first and then the roller bearing seized in the back of the spider shaft. Either way it is not going to be a cheep fix, the shaft is obsolete, I found one online for $320.00 and the other misc parts will probably add a few hundred more. Interesting thing was all the used ones I could find at salvage yards had that front part of the shaft damaged or the back of the shaft where the back bearing rides also damaged. Must be an oddball problem that shows every once in a while.