Hello, have a 744H that just jackhammer in and out of gear, like the TC won't lock it into gear. Intermittently does it in all gears, oils clean as a whistle. What's going on! Not letting me upload the video for some reason!
You can’t upload videos directly. You have to upload to YouTube first then link the video to a post.
https://youtube.com/shorts/Aoqfi2ou9_E?feature=share
Machine serial number? If you go into d01 of the monitor, what codes do you have?
you are sure it is from t/m, not axles. Like planetary wheel drive or diff? Symptons in all gears, F and R?
DW744HX556530 d01 just shows some bulb stuff. I posted the YouTube link to video
Pretty darn sure it's the tranny. The YouTube vid link shows the output shaft speed while in gear and it's not engaging/locking. When it actually does go into gear with brake on input shaft has a speed of 0. Yes different gears and f&r.
Was this the reading d053? Did you check the drive shaft from the engine to the transmission to see if that stops. Maybe the drive on the flywheel failed. The d053 (torque converter input speed) should always show engine speed.
Fully correct, converter input speed must be engine speed. However I doubt the issue is before converter as converter would dampen all vibrations. On the other hand a half broken input would give interrutions to t/m pump and t/m TCU would throw a slippage code. And pump would not create this kind of hard shocks. Could you provide some more Videos of entire loader?
I'm wondering whether the issues micht be created by limited slip diffs. Not sure whether Deere ever sold this kind of diffs, usually they got 100% lockable diffs. If limited slip diffs: With wrong oil in axles and running sharp bends this kind of stick-slip behaviour might occur. What happens during straight drive?
This is a straight drive, it's definitely a tranny, TC lockup issue. Complicated tranny with all the "soft" shift electronics etc. I believe the pressures checked out IIRC so leaning electronic
So it seems to be a ZF 5WG260 tranny with LUC. To exclude the electric impact please disconnect solenoid to LUC. See page 3, next to port 67. LUC must not engage in 1st at all, in other gears not below approx. 1200 rpm turbine speed. The upper pipe to LUC valve is feed, the lower pipe pressure to LUC.
Nice work! So I'll unplug the solenoid next to #67 and see what happens
Interesting this unit serial # is 4WG-260 636. The control unit ontop is 180* the solenoid faces the rear of machine. JD didn't make easy access. Haha, almost have to pull hydrolic tank to unplug that. Maybe the other end of the wires can be unplugged easier??
Hi Loveak, could you take a picture of type plate? Somewhere at bottom of housing towards articulation pivot. The 4WG260 did not get a LUC as far as I know, only converter. Does it look like attached pdf?
It looks similar just that the top plate area is 180* from the photo
My mistake. Yes it looks just like the 4WG images you shared. You can see in photo #2 the wire harness port in the rear of the transmission.
Hmmm, strange. So, again, as I see it. There is no converter lockup fitted on your tranny. Issue must be somewhere in geartrain of tranny or axles. I'd take out rear prop shaft, later also front prop shaft and check haviour of output flanges.
So I can't try to unplug the wire harness on the top back and try the transmission?
You can certainly do. Tranny will not shift at all, TCU will throw a few codes as all solenoids are unplugged.
Ok so it seems there is no point in trying to unplug it then. So back at square 1. Haha
Yep,almost. At least we know it's not the lockup clutch. Watching again your youtube file, I still have the impression the issue is closer to output resp. wheels. The shocks are pretty harsh, the tranny shafts and prop shaft would dampen torque peaks from input. What do you think, HEF experts? What about the idea to take out the prop shafts or jack up the loader. Both axles need to be off ground. Try to spin wheels by hand or bar. Output shaft goes straight through tranny and also spins output gear train. 4 gears. HEF experts, other ideas?
Interesting, so how does the output shaft engage the gear train. I'll play with diagnostic modes again, I remember a "input" and "output" mode. Can something be found here possibly?
The 4WG260 always needs 2 clutches for torque transmission. One so-called "input" clutch (KV, KR, K4) and one "output" clutch (K1, K2, K3). Output gear train is in permanent mesh with output shaft. See pdf. Diagnostic modes: I'm not sure what the Deere guys actually developped. However I'm afraid these modes were supposed to check input and output signals into and from TCU. Only electric stuff, no mechanical sense. So not sure whether this will bring you any further.
You could pull the drain plugs on both diffs and the transmission and see what falls out. I have a feeling you will see gear teeth. At least you can narrow your search.
And the magnetic suction screen in the line to the transmission pump, if it has one. @Bigbert should know.
I thought so too! Believe it or not the tranny oil was clean as new! No Grey sludge mettalics etc at all in tranny. This is an intermittent issue, most times it goes right in to gear and diffs work fine. Haven't chkd diff oils.
Still making me think it's #3 somehow. The electrohydrolic control unit ECU. The diagnostics are speed sensors. So....output shaft speed was telling me something prior isn't "locking" it into gear. I'll play with it later today and get some more ideas.
Nige is fully right, there is a coarse filter in the tranny. See PDF. You need to drain oil completely prior to removal. And the guys are right, too. I agree there might be a broken tooth somewhere. Intermittend issue? Can you check: The issue only occurs in 3rd and 4th forward? Not reverse, not 1st and 2nd F? Or the other way round? case 1: Broken tooth idler gear or K4 gear. case 2: Broken tooth KV oder KR gear.
Coarse filter and oil were crystal(well amber) clean! Lol. Suprised me, that was first I checked, no mettalics or Grey sludge whatsoever.
So we can almost exclude transmission as the troublemaker. Let us focus on axles. Usually front axles are more at risk, so I'd check this first. Remove prop shaft to rear axle, jack up front axle and try a ride. 2. Do same test with rear axle. Remove prop shaft to front axle, jack up rear, drive.
So I got a video that may help. It looks like the internal clutch isn't getting the power transferred to the output shaft. On the video the machine is in gear and "acting up" not going into gear as until the very end you see a rpm bump in the output shaft speed. The tranny sensors on machine are Torque input speed Torque output speed Internal clutch speed Output shaft speed When shifted into f or r and it acts up the output shaft speed won't lock into the output shaft. When it works right away when shifted into gear it's just a small bump in rpm and it's locked in gear. The machine doesn't want to change gears as well.
input shaft speed here is actually turbine speed, not engine or impeller speed. When switching into gear the TCU usually will try to go into 2nd, so KV and K2 pressurized. With proper pressure in clutches and loader at standstill, turbine speed, internal clutch speed and output must go to zero. With some peaks on signal due to backlash. But 1.5 sec after going into gear there must be zero on all of them. Output speed sensor is located on K3 gear with one mesh to output gear. So, with system for example in 2nd, engine running, input speed @900 rpm, internal 900 rpm, output speed somewhere, prop shaft at zero, there must be a broken tooth on output gear. How often will loader go into gear? Resp. how often does it fail? If you'd push or tow the loader 3 feet (to move prop shaft and output gear) would it pick up drive? Would you be able to measure pressure on control valve on KV and K2? Or did Deere fit some pressure pickups somewhere remote?
-Torque Converter Input Speed Sensor (Engine): This sensor is located behind the steering pump and monitors torque converter input shaft speed. -Torque Converter Output Speed Sensor: This sensor is located on the right side of the transmission and monitors torque converter out speed. -Internal Clutch Speed Sensor (Transmission): This sensor is located on the right side of the transmission and monitors the speed that the clutch packs are turning. -Output Shaft Speed Sensor (Transmission): This sensor is located on the right side of the transmission hydraulic control unit and monitors transmission output shaft speed
When shifted into gear sometimes it hesitates(does nothing) and return to neutral and back I to gear will put it into gear. Usually you have to run it for awhile to get this jackhammer problem to occur, the internal clutch speed drops to 0 when it operates properly, but when jackhammers in and out of gear it mirrors the input shaft speed. Last year we had a mechanic look at it and here were his findings.
I'm rather sure the pressures are fine on your transmission. The shocks look more like broken teeth somewhere. Pressures do not build up so fast and are not able to produce so harsh hits. Did your mechanic read out the TCU fault memory? There should be some faults recorded like slipping clutch K2 or K3 as speeds internal and output speed do no more fit together properly in situation of jackhammering. Did you ever check the main (fine) filter? Did you check the drain plug? Not quite sure whether it is magnetic type. Most likely there is/are at least one or two gears with some broken/worn teeth. However before pulling out unit we should have an indication for this theory.