• Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!

Issues with Lamtrac mulching machines

treemuncher

Senior Member
Joined
Dec 31, 2006
Messages
733
Location
West TN
Occupation
eatin' trees, poopin' chips
Has anyone else out there had issues with Lamtrac mulchers and final drive issues? My machine, an LTR8300-T, was not tracking straight due to a speed sensor on the travel motor being out. It read the speed fine in reverse but not in forward motion so the right track would push harder and the machine was always tracking heavy to the left if the joystick was kept in the straight forward position.

After conferring with the factory engineers via the internet and remote computer diagnostics, I replaced the $600 Rexroth hall effect speed sensor and that solved the problem, temporarily. After 6 hours of use with the new sensor, that sensor or something else went crazy. I suddenly did 2.5+ 360 degree turns as the right track remained in full power even though the joystick was moved to every other possible position. This is a fly-by-wire electronic controlled hydraulic system on this machine. Once I was able to get the machine back under control, it never pulled the donut stunt again but tracking was off. Scanning through the outputs on the computer screen showed no rpms on the right track when going forward. Next morning, checking the issues again and now NO rpm's showing in either forward or reverse on the right track motor. I DO NOT want to be loading, unloading or working extreme terrain and having this sudden "donut issue" happening again.

I'm working on trying to get this issue resolved so that I can put this machine to work and get an income with it. Several times, prior to the sensor going out, it acted as if something was caught in the tracks or the parking brake had come on as one track would lock up temporarily, just 1 or 2 seconds. No blockages were found and the issue was just part of or the learning of this new-to-me machine. Track frames were recently removed for frame updates and wiring to the travel motors was inspected and wrapped with fresh protective covers as were the hydraulic lines. No issues were evident on any of the wiring at that time and they were inspected due to the previous sensor problem.

If anyone else has experience with these machines, please give me some ideas as to what to look for. I did change out the final drive oils to inspect those for problems. Maybe 1/8" of extremely fine metal dust on the plug magnets but no other chunks or problems evident on either side. The right side did have more pressure build up that the left and possibly more fluid but hard to say exactly due to differences in drain plug positions when I opened the plugs. I warmed up the finals prior to changing the oil and replaced with a synthetic Mobil 220 SHC. Now, waiting for the factory engineers to help me with this via the laptop and internet, again. The $600 sensor was their last fix and that did not solve the problem.
P4060916a.JPG
 

Drifter

Well-Known Member
Joined
Oct 31, 2009
Messages
143
Location
Canada
First thing I would do if you haven't done it already is case drain test the motors. I would also change the hyd filters and cut them open and make sure you don't have a motor on it's way south.
 

Tones

Senior Member
Joined
Mar 15, 2009
Messages
3,059
Location
Ubique
Occupation
Ex land clearing contractor, part-time retired
If the track frames were removed did the final drive come of with them? Check all the wiring plugs, one could be loose somewhere causing this mischief.
BTW the 101 looks a little forgotten. :)
 

treemuncher

Senior Member
Joined
Dec 31, 2006
Messages
733
Location
West TN
Occupation
eatin' trees, poopin' chips
First thing I would do if you haven't done it already is case drain test the motors. I would also change the hyd filters and cut them open and make sure you don't have a motor on it's way south.

Case drain test? I'm guessing cap the return line at the pump and measure leakage from the motor case drain line over a period of time. I've been having a tough time determining filters without cracking the canisters open. I'm not sure where I will find acceptable leakage rates. Rexroth is quickly NOT becoming my favored hydraulic system because literature is not easily found and parts are EXTREMELY EXPENSIVE in comparison to other systems that I have become familiar with. Lamtrac's sensor was $600+ but getting it through a Rexroth dealer was even more expensive with a 6 week lead time on top of that.

If the track frames were removed did the final drive come of with them? Check all the wiring plugs, one could be loose somewhere causing this mischief.
BTW the 101 looks a little forgotten. :)

Track frames were removed in order to weld the axle assembly to the main frame. There was a Tech Service Bulletin issued because the bolted assembly was moving about and breaking the bolts. The fix is to weld underneath and up the sides of the frame. In order to access the side of the main frame, the track frames must be removed from the axle. While removed for service, the track frames were inspected for cracks, missing bolts, loose connector and all repaired. Track motors were inspected to make sure that they were tight, kept immaculately clean, well capped and all new o-rings on the fittings. All hydraulic lines and electrical lines were inspected for wear and re-wrapped with new protective covers. All electrical plugs were inspected for water, loose connectors and any other evident issues.IMG_20170322_104020462a.jpg

Lamtrac factory was supposed to call me this afternoon but never came through. I have been waiting for their help since last Thursday - not too impressed with their response time here. I've found a discrepancy in the computer code that might have something to do with the issues but I'm not trained in this stuff. 3 out of 4 pump values have a zero value but the 4th has a 5000 mAmp value - sticks out like a sore thumb in the code and does not look logical. Once their engineers can look at it, maybe they can answer my questions and get this figured out. I had a friend help me today and we inspected all of the wiring for issues but found nothing that could be identified as a problem. Major junction plugs were sprayed with WD-40 and coated in di-electric grease. Still nothing obvious at this point.
 

lantraxco

Senior Member
Joined
Jan 1, 2009
Messages
7,704
Location
Elsewhen
Rexroth motor with speed sensor failures.... hmm, possible causes would be metallic contamination, faulty sensors (not likely but it happens) or my guess, something is badly awry inside the motor. Typically those sensors work off a toothed ring that is part of the cylinder block, if for instance a bearing is becoming loose or a bad piston is throwing it out of balance, the gap is going to vary too much for the sensor to work or work properly. And it sounds like it's rapidly getting worse. The locking up may or may not be a mechanical issue inside the motor. My $.02 I would suggest yanking the cover off the final first and if no issues present themselves I would pull the motor out and hie myself to yon local pump and motah highway robbers for a teardown and eyeball session. But then that's just me.
 

treemuncher

Senior Member
Joined
Dec 31, 2006
Messages
733
Location
West TN
Occupation
eatin' trees, poopin' chips
Thanks for everyone's input so far.

Lantraxco, I am still thinking it is in the electronic controls. When the first sensor was out, I asked Lamtrac how to test it to verify that it was bad. "computer says it is bad, it must be replaced and we have no way to test it" So, I swapped the right and left sensors for verification my own way. Problem moved from right side forward to left side reverse - verified that the speed sensor was bad. Also, no marks on the sensor from any ring contact, no chips or trash in the motors nor the finals. When the track frames were removed for the servicing, all travel motor lines were disconnected and attention was paid to fluid cleanliness - all very clean, everything kept capped and new oring seals installed prior to re-assembly.

After the right track locked into full power on and the machine did 2.5 360 degree turns, that was when the right sensor acted as if it went bad again. While locked into power, no input from the travel joystick worked on the right side but left side input did still have an effect. First, no forward speed sensing. Next morning, no reverse speed sensing as well although it did work the previous afternoon and all of this on the right side, same location as the discrepancy on the code and same location as the first sensor to go bad.

I've also asked if I need to bleed out the brake release line but was assured that there was no need to do that, by the factory.
 

lantraxco

Senior Member
Joined
Jan 1, 2009
Messages
7,704
Location
Elsewhen
The weird part is it should have a limp mode, should not run away like that. But then not everybody codes the way I do I suppose.
 

treemuncher

Senior Member
Joined
Dec 31, 2006
Messages
733
Location
West TN
Occupation
eatin' trees, poopin' chips
Waited all week for Lamtrac to help me with the diagnostics on this case. Nothing but empty promises and excuses that engineering was unavailable to help at the time. I've even requested that they allow me to review the code and software to see if I can figure this out myself - no help in that respect either.

I NEVER want to own another "fly-by-wire"machine again. This issue makes me appreciate my more basic controlled hydraulic machines - easy to maintain and keep in operational condition. I prefer the computer stays in the office or in my pocket and out of the machine's control system.
 

lantraxco

Senior Member
Joined
Jan 1, 2009
Messages
7,704
Location
Elsewhen
I love modern technology... when it works. You can't always code around every fault, but in terms of safety and reliability the machine should do everything it can to protect itself and the operator, and still be of some use even if it has to go into some sort of limited limp mode because it's not getting the information it needs to perform as designed.

As a guess Lamtrac may have hired the control system design and the coding out to some outfit that specializes in that sort of thing. Having seen the result of this practice a couple times the usual result seems to be the typical built by deskbound engineer thing, they have very little real world experience and at best a vague idea what the operator wants that machine to do to make it work efficiently.
 

treemuncher

Senior Member
Joined
Dec 31, 2006
Messages
733
Location
West TN
Occupation
eatin' trees, poopin' chips
As a guess Lamtrac may have hired the control system design and the coding out to some outfit that specializes in that sort of thing. Having seen the result of this practice a couple times the usual result seems to be the typical built by deskbound engineer thing, they have very little real world experience and at best a vague idea what the operator wants that machine to do to make it work efficiently.

I think that you hit the nail on the head with that statement. I went to school with a bunch of those theoretical wizards that could not figure out how to operate a screwdriver in a real world applications, but they were book smart. I worked for my degree because I wanted to design stuff that had maintenance and repair as a primary goal. Little did I know that desk duty would ruin my life if I stayed with it.

The designers of the hydraulic control system of this machine need to know standard basics that most operators know (from experience). Pushing the blade drop function more than 50% went into float function (51%-100%) plus there is a power down button. Now why in the hell would anyone program the machine that way? Even my old Leibherr is power down all of the way (1%-100%) with a button for float function/quick drop of the blade when wanted. I thought that this was industry standard as 3 of my other machines were set up like the Liebherr, including the Barko. It is logical and works well. Push the joystick too far forward on the Lamtrac and it goes to float, right when you want or need power down. Just plain STUPID on the part of the programmers who don't have a clue.

Another issue with programming is that they thought it would be smarter to have the outside track go faster rather than slowing the inside track in order to make turns. How stupid is this move? It certainly does not work the way any normal dozer does with brakes and clutches. Generally, when I am turning, I am around timber or obstacles that I don't want to hit with the machine and slowing it for a turn makes more sense than speeding it up. I would really like to flog their programmers and beat some sense into them with a smart stick. I've been told that this issue, with the tracks, can be resolved by changing variables and I will be asking that to be done when ever they finally get around to figuring this machine out.

As a former instructor in a machine shop course told us during a lecture one night, "For those of you who go on to become engineers, NEVER THINK THAT YOU KNOW EVERYTHING. Always ask the machinists on the floor for their input on how to build something the easiest way. They will know more than you can ever learn from a book. They can save you embarrassment, speed up production and save the company money."

I never forgot that lesson. These programmers should have consulted with operators prior to writing any code or trying to build what looks pretty on paper. Functionality make for efficiency, efficiency is standardization and standardization makes it more functional.
 

treemuncher

Senior Member
Joined
Dec 31, 2006
Messages
733
Location
West TN
Occupation
eatin' trees, poopin' chips
A quick update -

I went through all of the wiring connectors and looms with an Ohm meter for everything that was connected to the final drives. No broken or abraded wires found during re-inspection. All pin and socket connectors were disassembled, cleaned and soldered to the wires which resulted in a drop in resistance of all wiring from the main computer junction to the final drive motors when the wiring was reconnected. This still did not repair the problem.

I did finally break down and replace the sensor that worked for a total of 6 hours, for another $600. That fixed the problem with that tracking issue so far. I still feel burned over a 6 hour working lifespan for $600. Still no word back from the manufacturer if they will cover this or not.
 

lantraxco

Senior Member
Joined
Jan 1, 2009
Messages
7,704
Location
Elsewhen
If you haven't, I would get ahold of your local Rexroth dealer, compare pricing for those replacement speed sensors... seems about double to me, but then that's why I use Danfoss pumps and motors.
 

Tones

Senior Member
Joined
Mar 15, 2009
Messages
3,059
Location
Ubique
Occupation
Ex land clearing contractor, part-time retired
Have you considered removing the electronics and converting it to good old fashion pilot control? Maybe a little expensive but at least you will have a machine that works and stays working. Humm, sadly it must be a thing with mulcher manufacturers not calling back. I think sometimes it's easier to pull teeth from a ducks bill than get the required info.
 
Top