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Cub Cadet 1250 jerks forward/reverse

451 Views 6 Replies 6 Participants Last post by  Fuddyduddy1952
I have a low hours Cub 1250 hydro that runs well except when I start it cold at idle putting it in reverse does nothing. Forward works but jerky. If I need to back up I rev it some then it jerks going back.
I replaced both check valves because they were dripping a little fluid. Once warmed up it's better but still not smooth. Running (I'm guessing) about 2,000 rpm I ease it forward and it usually "pops a wheelie" then goes.
Sometimes when I hit the brake which puts it in neutral it wants to go forward or reverse (intermittent). I made sure used correct hydro fluid and it's full.
Wheel Tire Hood Vehicle Automotive tire

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Any history on the machine? Do you have a service manual? I’ve had smaller closed hydros act like that because of a trapped air bubble in the transaxle. I doubt your is a closed system though so that is not good. Got to be some cub guys on here. Must be a similar or same transaxle as a JD.
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Sounds like linkage worn out and/or dampener has failed.
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Sorry, I have never worked on a Cub transmission but it does sound like a flow issue in addition to maybe a linkage issue. Does it have a transmission filter or screen that could be partially plugged? If it has a filter, is it the correct one and not a will fit?
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Before I got hooked on 332 Deeres, I had a lot of 50 Series Cadets. As they got older, the jumpier they would become. I would suggest the following:
1. Take the tunnel cover off.
2. With the engine shut off, grab/wiggle the hydro rod going to the hydro linkage (to the left of the driveshaft).
3. ANY wiggle in the rod from either end will make the hydro jumpy.
Here is what I would suggest (and "Yes. it's a long story):
1. Check that the rivets in the hydro handle (under the dash on the right side) are tight. The rivets are on the bottom of the flexible flat plate to the linkage. If not, take the handle out and re-set the rivets. Usually a couple good whacks with a hammer and the rivets on a hard metal surface will tighten the rivets up.
2. If/when you take the handle out, check the fit of the handle shaft into the support hardware on each side of the dash support. I have had to rebush the fittings with bronze bushings from a local hardware store after cleaning up the shafts. If you have to do this, add a dab of grease into the bores when reassembling.
3. Check the front and rear tie rod ball for wear. Again, if loose, replace it.
4. Usually the slop is in the linkage at the cam plates just ahead where the linkage goes into the hydro pump. Although the material is hard as nails, it will wear in both pivot points. There is a small plastic bushing that can break up on the forward pivot, so refer to the Parts Catalog for more details/replacement. There is a small snap ring (that I usually refer to as a "Jesus Spring" because if you aren't careful taking it off, IT WILL GO FLYING and shortly after that you will say: Jesus, where did that go!) if/ you need to check for wear.
5. Take a HARD look at spring set up that is held between the two linkage plates BEFORE YOU TAKE THE PLATE OFF. In that area, there is a larger spring with small metal "T's" on each end of the spring that actually has a smaller spring inside the large spring.
Note: If you want to take the front cam assembly off, there are 2 bolts that hold it into the hydro assembly. Loosen the bottom bolt, but take the top bolt out. It should lift straight up from there.
Generally in my experience, the majority of the wear/jumpy issue is in this area. Once you get everything apart, it will be easy to see the wear in the plate (from vibration) and/or the condition of the springs. Weld/replace the plate as needed to bring everything back to the original dimensions and flat/smooth before re-assembly. The light spring (that pilot the "T's) is a "teaser" spring to get the linkage moving (when the hydro handle is moved either direction). The heavy outer spring is for when you "nail" the hydro lever so there still is some feel to the lever movement.
6. IF YOU HAVE TO REMOVE THE CAM PLATE attached to the hydro pump shaft, it is usually easier to take the fender pan off to get at it.
7. BEFORE you take the cam plate off on the hydro pump shaft, confirm there isn't any free movement between the cam plate and the shaft. If there is, it will need to be corrected as well.
8. At that point, hold the hydro pump shaft on the right side of the hydro and try to wiggle the left side cam plate and shaft. If there is ANY free movement, then your problem just got worse as that indicates the wear is between the shaft on the left side and the swash plate on the inside of the hydro. The good news is that isn't very common on Cadets to my knowledge.
9. If you are still with me to this point, change the hydro oil and filter by taking the rear cover off the back of the rear frame. If the ol girl has been setting (and the Hy-Tran did it's job), you might be a bit surprised at what you find in the bottom of the reservoir. I opened one rear end up to find there was 7 quarts of basically jello. Hy-Tran is designed to hold a certain percentage of water. When it gets past that point, it turns to jello. If you have that issue, take the metal tube off going from the bottom of the reservoir to the hydro inlet and flush with brake clean as needed. Once it is cleaned and dried out, put the rear cover on and refill the reservoir to the bottom of the plug. (And yes, I recommend a Cub Cadet filter and Hy-Tran)
10. After you get it all back together, with a couple of jack stands raise the rear wheels off the ground.
11. Go back to the bolts in step 5 and loosen them so the cam plate can move. Raise the cam plate they are holding as far up as it will go. Snug (not tighten) the bolts.
12. Start the engine and run at an idle. Slowly move the hydro lever through the hydro slots both ways. Note: Neutral will typically not be in the center of the slot at this point. Don't get nervous as you are about "home"!
13. Once the hydro has ran for a couple minutes in each direction, place the hydro lever into the "Neutral" position. Note: The rear wheels will be turning at this point.
14. Using a long punch and hammer, lightly tap on the top end of the cam plate with the snugged bolts. As you are moving the cam plate down, the rear wheels will start to slow down, then eventually stop (which means you have found "neutral"). If you go too far, the wheels will start moving in the opposite direction. If that happens, shut the tractor off, loosen the cam plate bolts, move the plate up and try step 14 again.
15. Now, take the tractor out and see how it reacts. It should be "good to go"!


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Had the very same problem with my 1650 years ago. I wouldn't be surprised if it was 332 Guy who helped me fix it whilst wearing his Cub Cadet hat on another forum. His point form explanations really improve readability too. (y)
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For whatever reason I used it yesterday and it was smooth as silk! I haven't had time to check anything out but it worked perfectly.
I assume something in the hydro system was "sticking"...who knows. When I tap brake/clutch it goes right to neutral then from idle to wot forward or reverse it goes smoothly, no jerking.

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