Dealer Charges Customer $2000...and now it's WORSE!! (Kubota Tractor)

wow hey everyone welcome back to pine hollow out of the agnostics today we're working on some farm equipment this is a kubota early 2000's uh l 3130 three cylinder diesel engine with the gsd this is the glide shift transmission so it's kind of a electric electronically controlled manual where the clutch is activated by hydraulic pressure you can shift on the fly you don't have to use the clutch every time you want to shift the gear so the customer complaint here actually he brought it here from over two hours away on a trailer and he said that whenever he puts in gear and releases the clutch it goes boom boom boom like five times and then it goes at its normal speed every time you shift from reverse to neutral or forward anytime you change direction it does this five kind of shocks and then it goes also when you're shifting gears on the fly it's not smooth it goes boom that's not supposed to happen so let's look up some information on this thing i do have the the service manual he gave me a pdf of it you know electronic version so let's do a little research and see what we want to uh want to check first let's take it for a test drive and see what it does all right let's start this thing up so this is the clutch these are two brakes right wheel left wheel so we'll release the parking brake and lift up our um bucket so when you push the clutch in let's say we want to go reverse pick a gear somewhere in the middle and then start moving boom so pretty hard shift try to change gears it goes uh okay let's try forward two three four okay so i did it like four or five times and then it's smooth when you shift the gear very harsh so that's what it does so now let's look up some information and see if this is an electrical problem or a hydraulic problem now he already spent i think two thousand dollars taken to the dealer they replaced the clutch packs in this transmission and he said it only made it worse so let's uh let's see what's going on here all right so for this gst here's a characteristic and system outline it has a you know smart panel that controls solenoids so it's a new version uh it controls the gear shifting and clutch operation hydraulically and ugsd has a function to control these operations electrically okay 12 4 and 8 reverse speeds can shift only by operating the main shift lever and shuttle shift shifter without the clutch operation as well as uh the former gst system movement gear shifting according to oil temperature and traveling speed can be achieved by having electronically controlled gst systems smoother operation okay now so you can read about all this stuff electrical control system so we have these components there's the ecu electronic control unit so basically you know tells you if you have any short or open circuits and then it's the attack sensor pressure switch this switch is detect gear change completion hydraulic clutch operation and is equipped on the gst out the switch is turned on when the pressure of the valve becomes higher than 71 psi turns off at 50 psi okay so this is the little valve body there we have a speed sensor okay this is interesting right here so here's how it shifts so gsd leverage shuttle lever uh is at the desired position output voltage of the gear shift position sensor is output to the ecu it detects the position and the oil is sent to the desired shift piston a pressure in the circuit is raised because the movement of the shift piston shuts the shift check pin when the pressure on the circuit reaches 71 psi the pressure switch becomes on and then when it turns on ec detects present condition traveling speed engine speed and temperature from various sensors and pressure and hydraulic clutch is raised according to the respective conditions so basically it shifts and then it gently engages and ramps up the pressure in the hydraulic system with this proportion reducing valve okay there's the whole hydraulic layout and again you can read all the details right here by means of pressurizing and circuit clutch valve 24 is actuated oil flows low pass 25 proportioning reducing valve to the clutch the oil flow flows until becoming the compound pressure which is both setting pressure closing low pass valve control indication so you can you can read about this stuff it's you know pretty complicated to see exactly which valve does what because pressure in the gst clutch is gradually pressurized by function of the proportional reducing valve 26 clutch is able to engage without shock and smoothly when the pressure in the circuit rises the system pressure pressure is maintained okay so just by the symptoms i'm worried about this proportion uh what is it called proportional proportional reducing valve and also this oil pressure switch that's supposed to close at 70 psi and let's read about the shift check valve just worry about the clutch not the shifting or anything proportional reducing valve okay after gear shifting is completed this valve has function which gradually rises the pressure in the clutch in order to make clutch engaging for without shocking smoothly when gear shifting is completed the pressure switch is turned on by means of turning on the pressure switch then the ecu ramps up this valve okay cool so these two components are key to smooth clutch operation there's a clutch valve that's a mechanical valve there's the clutch itself so that's the background information now in the electrical diagram i located these two valves you have to zoom way in so proportional reducing valve two wire and then pressure switch gst also two wires they're located right next to each other and finally there is a procedure on checking hydraulic system pressure you can use a pressure gauge at the various ports setting pressure all this good stuff clutch pack pressure so you can see it's much more complicated than just having a regular manual clutch so since we have four wires that worried about two to the oil pressure sensor and two to the proportioning valve i'm gonna hook up a four channel scope to all four wires and see what happens when this thing is driving around all right so here's here's the gsd valve body assembly and conveniently we have the two pin connector for our proportioning valve right here and two pins for the oil pressure sensor i'm just using needle back probes going past the weather pack and then on all four wires all right so we got four channels on the screen let's turn the key on okay so what do we see here the blue stays at zero the red is pulsing then the yellow's at zero and the green is around 12 volts let's see what happens when we start it so wow so you saw what happened there there i shut the key off so it looks like the proportioning valve is doing its thing it's just pulsing whatever duty cycle that the ecu is commanding it however this oil pressure switch never change state now i'm assuming there's a power feed here or you know it's supposed to be on or up we don't know if it's closed or open but regardless we're not seeing a change of state in this oil pressure switch one line's always high the other one's always low no matter what that's not correct so right off the bat i'm going for this oil pressure switch we might need to check the hydraulic pressure but unless let's at least check the pins and the fitment make sure everything's tight there and we can even check the continuity through the sensor obviously we have it's open right now because the two lines are at different voltages but when it closes those two lines should be at the same voltage right maybe we have a power feed and then when it closes the second line gets pulled up and then the computer sees sensor is good so let's uh let's explore that let's go right for the oil pressure switch all right so i took off the connector off this oil pressure switch i see all the it's a little cracked i mean in terms of the uh the switch itself a little bit but the clip is still there let's take a cl close look at these pins oh that's interesting so i don't know if the camera will pick this up especially in the dark but you guys see that one pin is all the way you know you can see it exposed the other pin is kind of uh not exposed like the wire got pulled out a little bit and the pin might not be touching that contact so let's uh let's try to fix that plug this thing back in and see if there's any difference on our scope captures and drivability so i took off the white little retainer and sure enough you can really clearly see now how far in that one pin is depressed that's pretty crazy so for the yellow wire that pin is way in there let's see if we can extract it and it should clip in just like the other one is let's see if we can either push it through and get some pliers all right so i just pushed the yellow wire through and that pin came out and is now locked in by that plastic tab so i think how it works is you gently release that tab and then you can pull the wire through again i don't want to do any more damage here yep so basically it is in all the way now let's put this back on now does it go this way yeah i think you should go in this way and then those little tabs lock in okay clips in like that someone must have pulled really hard on that wire because they don't they seem to be locked in place just fine and put the probes back in plug this back in and then see if anything changes all right let's roll the scope see the yellow channel now it's going high and we put in neutral it goes low that's a big difference go forward so i think my connection might have been disturbed there on the green trace no more surging [Applause] there we go put in reverse again very smooth let's see where's where are the lights here i don't know forward a little more bunny maximum speed oh yeah now we're cruising very smooth you see the oil pressure switch goes down and then up the reverse [Music] this is amazing it's fixed no press required that guy's gonna flip out when he finds out he didn't need a clutch pack look at this so i'll be honest i before i even made the video i fixed the tractor when i first plugged in the scope it drove beautifully and before i plugged in the scope it was surging so i knew i was going for one of those connections but it just proves the point that a lot of these repairs are just like their wiring problems or connection problems not it you know you're suspecting clutch packs and stuff this truck this tractor only has a thousand hours on it so the clutch packs are probably fine so the owner will be very pleased to find out that this tractor is fixed so just diagnostic time and put the pin back in that's it thanks a lot for watching and we'll see you next time bye a little bonus footage on the kubota i want to perform this uh proportioning valve fine adjustment you can do that through the ecu control panel it says when the ecu or gst valve is replaced this adjustment as required well they did replace the whole entire clutch pack assembly so i think this is a good idea to do this so you can adjust you know the actual shift lever that's fine that shows fine on the display so we're going to do this um p valve adjustment and then we can fine tune the gst shift shock fine adjustment but this this is the main one so let's follow these instructions on the tractor you gotta hold these two buttons down while you start the engine all right the p-valve calibration is complete keep pushing the button okay turn it off take it for a test drive let's go over there and scoop some manure this tractor's fixed it's awesome

Channel: Pine Hollow Auto Diagnostics

Views: 119,237

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Id: pT96YKMjDjs

Length: 21min 38sec (1298 seconds)

Published: Thu Dec 16 2021