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Issues with Terex TA35

Discussion in 'Other Earthmoving Equipment' started by nlabrecque52, Nov 13, 2019.

  1. nlabrecque52

    nlabrecque52 New Member

    Joined:
    Nov 12, 2019
    Messages:
    4
    Location:
    New Hampshire
    This could end up being a long post, so I apologize ahead of time. Its my first time here, and Im assuming the more information I give the more accurate the responses will be.

    I purchased a 1999 Terex TA35 articulating dump truck a few months back (serial number A7761027) from an online auction. When the truck arrived, I had to let it warm up for about 15 minutes before reverse would engage to pull it off the trailer. I also noticed a significant leak coming from the general area of the transmission. However long story short, the truck drove forward and backwards upon arrival. I contacted a local Terex boom truck dealer and they said they had a tech experienced with these trucks and sent a guy out.

    Trying to get a jump on the simple work myself, I unbolted the cab, disconnected the quick connect wiring that comes in behind the panel near the cab door, and then realized I needed to move the truck to a place he could more easily work on it. When I reconnected the electrical, the tech told me I switched two plugs, one to the ECU other to TCU, and in turn cooked the TCU. He said that he couldnt diag a leak without being able to build pressure in the transmission. $5k later I had a new TCU that he installed, fired the truck up, and instantly found a roughly 4inx3in hole in the stater that had been filled with a piece of tin and some JB weld.

    I Ordered new Stater, Tech removed cab, installed etc etc - Now with new TCU truck would move slowly in forward 1st gear, however wouldnt do anything in reverse, regardless of how long I let it warm up. Also had "Stop" light flashing as well as the code for transmission calibration needed. Tech called it a night, telling me I needed an AEB starter to calibrate the transmission. I contacted Centranz, the place I purchased the TCU from and spoke to a guy who was very helpful, and told me I needed to check pressures at the nipples behind the cab. For entertainment I plugged in the old TCU and surprise surprise, the "Stop" light went away as well as the code for the calibration. I check pressure and had 225psi in 1st, however it dropped below 150psi when I shifted to reverse. Gentleman from Centranz basically told me I needed a reverse clutch pack, and spent the next day on the phone with the technician I have hired having him open the valve body to check if something was actuating etc, and the tec at the end of the day had cut open the two main filters that are behind the cab, and found some pieces of brass, the he brought to me as evidence that the clutch pack was toast as that was the only place in the system brass shavings could come from.

    I have now spent $10k +/- in parts and $12k +/- in labor.....I started with a truck that drove forward and backwards with a leak, and now have a truck that is inoperable. If I take his direction and order a reman tranny ($26k from Centranz) it will come with a new stater. The obvious issue is that I will have spent $22k +/- on a TCU that the truck didnt need, and replacing a stater, that if I purchase a transmission, the new one will come with. The entirety of my $22k will be wasted.

    Either way, Im not convinced Im in need of a Transmission, and Im in hopes that someone can give me some direction for additional diag etc that may give me other possibilities, or a place I may find a more reasonable cost effective way of getting this transmission fixed.
     
  2. Bigbert

    Bigbert Well-Known Member

    Joined:
    Jan 2, 2016
    Messages:
    149
    Occupation:
    Consulting Engineer
    Location:
    Germany
    Hello nlabrecque52,
    sounds like a real mess.
    On ZF 6WG 310 there are two clutches equipped with sinter discs: KR and K1. some brass debris in filter does not necessarily mean a warped KR. A warped KR ususally created a brief move backwards when shifting from neutral into forward.
    However to get more clarity about the real situation:
    Please disconnect hose from control valve to KR/K2 shaft, plug it and see whether main pressure stays at 225 psi in reverse.
    On the other hand: Which fault codes could you see on transmission display in cab?
    Usually you are not able to burn a TCU with CAN wires mixed up. I'd rather assume corroded pins. New TCU will ask for AEB, however you can also drive and test w/o having AEB passed.
    May I ask you a question? What is the "stater" (sorry, I'm German)
     
  3. Vetech63

    Vetech63 Senior Member

    Joined:
    Aug 10, 2016
    Messages:
    2,645
    Location:
    Oklahoma
    Tough situation. Do you have any fault codes on the display and if so what are they? They are usually a letter and and number. I’m wondering what you are calling a stator. The transmission has a retarder on it and the front cover looks similar to a stator design. If I am remembering right, I don’t believe tcu and the ecu plug ins are the same
     
    mg2361 likes this.
  4. Bigbert

    Bigbert Well-Known Member

    Joined:
    Jan 2, 2016
    Messages:
    149
    Occupation:
    Consulting Engineer
    Location:
    Germany
    Okay, now I understand: The stater is the retarder front housing (with the hole in it).
    In fact this is the stator of the retarder, cast aluminum. With the retarder not actuated not pressurized.
    Did the Centranz guy do the readout of TCU with ZF Testman? Please try to get hold of it to get a clue about fault codes stored.
    Plugs on ECU and TCU are definitely not the same, only a 2 wire CAN connector inbetween. (And completely different location).
     
  5. nlabrecque52

    nlabrecque52 New Member

    Joined:
    Nov 12, 2019
    Messages:
    4
    Location:
    New Hampshire
    I am so sorry- I created this account, asked the questions, and somehow never got notifications about responses. Thank you so much for taking the time! Im uploading a picture of the stator.

    Quick update- I tried running the aeb starter program with both TCU's. Ran into error code "FO" which I believe is "out speed not zero"- so I replaced the output speed sensor. When I removed the sensor there was a big piece of clutch band on the magnetic pickup of the sensor. Truck now moves forward, but not in reverse. When the clutches for reverse pull in during the calibration you can all but feel them slipping. I would guess its the clutch packs, however my last hope I would think is in the valve body and something prohibiting the clutches from building or maintaining pressure. I removed the valve body, and brought it to my friends shop so that he can bench test it for me.
     

    Attached Files:

  6. nlabrecque52

    nlabrecque52 New Member

    Joined:
    Nov 12, 2019
    Messages:
    4
    Location:
    New Hampshire
    The mechanic was an idiot, and my old TCU works fine! Now I do however have a TCU if anyone needs one! I uploaded a picture of the "stator" and I apologize for any of my ignorance. Im far from a mechanic, which of course is leading to 90% of my frustration. Again I apologize for not responding MUCH earlier, and truly appreciate everyone taking the time to help/offer insight! Im working in Chicago for the next couple days however as soon as I get home I will check what the codes Im getting on the dash are.
     

    Attached Files:

  7. Bigbert

    Bigbert Well-Known Member

    Joined:
    Jan 2, 2016
    Messages:
    149
    Occupation:
    Consulting Engineer
    Location:
    Germany
    Hi nlabrecque52,
    crazy story.
    May I ask you some more questions?
    1. "FO" during aeb means too high output speed during clutch calibration, right. Have you been able to complete aeb with new sensor? Which result? All clutches fine? Or KR blinking?
    2. Have you been able to block KR hose at control valve to see pressure being up at 225 psi in reverse?
    3. Any fault codes on display when trying to go in reverse?
    4. When driving forward truck will move in 1st (KV/K1) AND 2nd (K4/K1)? (Select gear with lever to left or right)
    5. Again, the transmission will work also without having aeb passed, shift comfort might be a bit worse.
     
    Vetech63 and mg2361 like this.
  8. Dave Neubert

    Dave Neubert Senior Member

    Joined:
    Jul 19, 2018
    Messages:
    559
    Location:
    Monroe NC
    Have not worked on a Terex but heard that they are money pits a trans is very pricey for it my recommendation would send it down the road and cut you loss