Case 1370 HELP!!! Please

[Dylan Zitterich]

Recently purchased a 1370 and need help with some problems. First off the parking brake wont disengage and the light on the dash keeps flashing. When you pull the lever in the cab nothing happens. Where the linkage goes into the transmission, you can move the shaft out of the rear end about a half inch. Second when you push the clutch down the tractor shuts off instantly. Any info would be appreciated.

 

[AllanC]

The brake light is controlled by a switch at the base of the brake lever. It has an arm the lever pushes on to turn off the light. The engine stalling problem sounds like a powershift problem. It's trying to go into two gears at once instead of no gears. There is no regular clutch in these. It's all done in the powershift unit. Need a manual and do some troubleshooting!

 

[D&Dservice]

The C4 clutch in the powershift is seized together, time for terdown.

 

[mEl]

an educated guess would be that either c1 or c3 pilot spool is stuck, remove it by useing a machine screw screwed into the end and work it free flush out the bore and try it

 

[Dylan Zitterich]

My brother in law is a mechanic and he didnt think the lever was going far enough to shift between first or second gear, so that may be the problem, is there a way to bypass the parking brake?, its stored inside anyways.

 

[Jim B]

No, the engine stall is not caused by the manual controlled (1st,2nd,3rd gear) portion of the transmission... the problem is within the Powershift (RPS) portion.
Prior entries are good advice.

The hand brake normally will not stall that big 504 Turbo.
I've mistakenly not released my hand brake on our 2470 and didn't even realize it until I could smell it. It really intended as a parking brake.

 

[Dylan Zitterich]

What I meant was, I was wonder if its stuck between 1st and 2nd gear

 

[mEl]

please check the pilot spools first before doing any serious teardown, i have worked on dozens of these and the pilot spools are the first place i would look then go from there. C4 is applied in reverse regardless of where the clutch pedal is and the fact that it stalls when you let the pedal out indicates that either C1 or C3 is applied when it should not be as C2 and C4 are the combo that gives you reverse so one of the others is giving a 3 clutch combo that stalls the engine, in all likelyhood if the problem developed without any grinding or strange noises it is a stuck pilot spool. you have to know how the clutch combos are paired to properly diagnose the RPS34, thats where lots of experience or factory training plus hands on is invaluable

 

[mEl]

I need to clarify that C4 is the clutch that stops the planetary drum for shifting the 4 speed so it engages when the clutch is down, thats where it comes into play in your scenerio

 

[Jim B]

mE1,
With your extensive dealership experience and training you obviously know the RPS34 better than most anyone!
Although we've farmed with Case machines since the early 70's we are somewhat new to repairing the Powershift tranny. We have both a 2470 & a 2870. The 2470 has been in use now for about 14 years and recently it needed the Powershift repaired. Turned out to be the common problem of shearing the 6 bolts attaching the C2 & C3 hubs together.

Anyway, to do the farm-shop repair I needed to educate myself as to the workings of the RPS34. The Case Service & Parts manuals were a great help. I learned that the C4 applies whenever the clutch (inching) pedal is depressed, which explained the planetary "whine", because reverse is created when the drum is locked. My question, if you would be so kind as to respond, is: why is that necessary "for shifting the 4-speed"? I cannot see how locking the C4 drum necessarily stop rotation within the 4-speed?

Thanx, in advance, for your reply
Jim B

 

[mEl]

Jim B, in actuality it is not a true trans brake, you are right in your observation, slight warpage in C2 plates will make selection of a gear difficult, It is applied by clutch depression and drops out as the inching pedal(clutch)is released, except in reverse where it is applied by lever selection. looking at the mechanics of it if the drum is stopped, the oil drag of C3 is what would drag the shaft to a stop the way i see it, anyone out there who would want to add to this discussion , please post

 

[Jim B]

mEl,
Thanx for the reply and comments about the RPS C4 clutch actuation acting, somewhat, like a trans brake.

It was a really nice, 40 degree, fall day here in SE Michigan so I decided to fire-up the 2870 and chisel plowed some of our Soybean ground. Because of our discussion about the C4 I paid close attention to the function of the RPS34.

The RPS oil & filters were replace just last year when this Ol' girl was brought into our operation and it runs and shifts quite nice, especially in warmer weather. Much more HP and traction than our 2470.

The following are my observations:
> After a 10 min. warm-up, there was a little 'grinding' while shifting the 4-speed into 4th gear.
> While driving to the field, Power Shifting the RPS up thru the gears at about 1500 RPM, the shifts were harsh and solid. RPS oil still kinda cold.
> 10 mins. later, arrived at field & downshifted to 2nd gear, less grinding noted than earlier when colder. Under draft-load of plow the up-shifts & down-shifts of the RPS were solid but not nearly as harsh as unloaded.
> Plowed for about 3 hours, everything normal... love that HP! and 4-wheel steer. Then came home for lunch and noted no more grinding from the gearbox when she was fully warmed up.

So, I suspect any "oil drag" within the C3 is not enough to act as a trans-brake, at least when the tranny is cold. But that seems intuitively backwards to me as any oil-drag should be greater with cold oil in the 4-speed as well as the RPS ??

After further thought about the logic of C4 application when the inching pedal is depressed... could it be related to the (normal) loss of RPS lube-oil pressure when the inching pedal is depressed? Perhaps locking the planetary drum minimizes friction (motion) within the PRS ??

Again, thanx in advance, for your comments

 

[mEl]

Those are good observations and a well thought out explanation of the operation, first, it is typical for the shifts to be harsh on hard ground, especially on roads and in 4 th gear, in soil where the tires can slip a bit and in the lower gears under working conditions it is less noticeable. The reason obviously is the amount of ratio change between the ranges and the speed that the clutch applies, the 28 has a huge engine with lots of stuff and soft application would induce heat and resulant wear so shifts have to be necessarily firm, you are not saying about jumpy shifts or loss of drive between shifts so your retard screws adjustments must be fine. Since C3 splines to the mainshaft on the inside and the drum outsde, it would follow that if the drum was stopped the drag between the internals and externals should have a slowing effect on the mainshaft and you are correct that cold oil should slow it more rapidly so i suspect there are other forces at work to give you better action warm. Yes to the idea that C4 application is related to the reverse lockout spool, it contains lands which direct oil to different functions depending on position and loss of pressure to the lube circuit gives some very interesting symptoms such as loss of drive when the steering is brought against relief,as steering return oil actuates the reverse lockout, this can happen if the 8 gallon pump gets marginal and the steering returm flow completely stops when the steering is cramped. again thank you for your insights, there is always more to learn isn't there?

 

[mEl]

Those are good observations and a well thought out explanation of the operation, first, it is typical for the shifts to be harsh on hard ground, especially on roads and in 4 th gear, in soil where the tires can slip a bit and in the lower gears under working conditions it is less noticeable. The reason obviously is the amount of ratio change between the ranges and the speed that the clutch applies, the 28 has a huge engine with lots of stuff and soft application would induce heat and resulant wear so shifts have to be necessarily firm, you are not saying about jumpy shifts or loss of drive between shifts so your retard screws adjustments must be fine. Since C3 splines to the mainshaft on the inside and the drum outsde, it would follow that if the drum was stopped the drag between the internals and externals should have a slowing effect on the mainshaft and you are correct that cold oil should slow it more rapidly. Remember that C2 is also in play here and so it must be that the reduced friction because of the warm oil is causing less drag on C2 so the tendency for it pull the mainshaft along is reduced. Yes to the idea that C4 application is related to the reverse lockout spool, it contains lands which direct oil to different functions depending on position and loss of pressure to the lube circuit gives some very interesting symptoms such as loss of drive when the steering is brought against relief,as steering return oil actuates the reverse lockout. again thank you for your insights, there is always more to learn isn't there?

 

[mEl]

sorry about what appears to be a double post but i added more info that i think will help clear up the drag issue, again sorry

 

[Dylan Zitterich]

I dont know if it makes a difference but I can only get the clutch about half way down, before it gets caught up, and then it will go all the way down and shut the tractor off. I hope the pilot spool is what the problem is, it only has 3700 hours on a 74 model.

 

[mEl]

The pilot spools are ABSOLUTELY the first place to start.

 

[Jim B]

Yes mEl, "there is always more to learn" especially with a smart teacher.

Your comments and explanation about C3 internal 'Drag' acting somewhat like a
Trans Brake now sounds reasonable... but we've determined that it seems to work better when the oil is hot, which doesn't seem logical??

Well, this made me think deeper into the means-of-function of an RPS 'Trans Brake'.
My thoughts are... as you stated, the "C2 is in play here" and perhaps that's a lead toward further explanation of controlled 'Drag'! As we know; when the inching pedal is down, not only does the C4 engage (locking the planetary drum and 1/2 the C3 plates) and the reverse lockout spool releases the manual valve due to the dumping of Lub pressure, but the Lub oil flow into the C2 also stops. This loss of Lub to the C2 may actually cause it to 'Drag' a little and that friction would try to turn the output (main) shaft in a reverse direction as the hub of the planetary and 1/2 the C2 clutch plates are now turning in reverse. This low-torque reverse-rotation perhaps works in unison with the earlier discussed C3 'Drag' to promote function like a Trans Brake when Hot. Plus the 4-Speed gear-train (which is submerged in the oil reservoir) is spinning forward so any reverse torque would help stop rotation.

What do you think? Sound reasonable?

Another consideration… when, or if, the 4-speed spins backwards, during cold-oil shifts, the resultant ‘grinding’ would be on the backside of the gear teeth. This wear would be unlikely to cause gear failure because it is not on the high-torque loaded front-side of the gear teeth.

Thanx for the dialog. I really enjoy a tech-talk about the hidden-engineering of a machine and as you said: "there is always more to learn". I LIKE IT !

 

[mEl]

Jim, Another way of looking at the loss of lu be flow would be that the absence of oil between the plates would actually decrease the amount of drag as oil between the relatively close fitting plates would cause a "torque converter" effect tending to drag the other plates along!! Anyway, it is an interesting discusson and I have been challenged by it and hope that others have been helped. Anyway, it is a great transmissin and I have seen in excess of 7000 hrs on a 970 with the very early powershift and that one would have had piston seals without the wire expanders., any more thoughts, thank you as well