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catmastertech
catmastertech, Technician
Category: Construction and Road Equipment
Satisfied Customers: 2366
Experience:  Field service technician for CAT 19 years.
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I am working on A Cat D250E Articulated truck PIN#5TN01600,

Customer Question

I am working on A Cat D250E Articulated truck PIN#5TN01600,
Transmission # *****
Engine Serial-49S02988, Model-3306.
I have ran in to a few problems that I need help with.
My main problem #1: is that I cannot get the truck to shift into any other gears than 1,R1,R2,N. When i want to shift into 2,3,4,D The EPTC recognizes that I selected the gear through the gear lever switch but will not shift when I attempt to drive.Problem#2: The bed does not raise when I move lever to raise position. The fuse for this application keeps blowing out on me every time I attempt to raise the bed. Although this continues to happen, on the EPTC it will read that the body is in float mode when i have lever switch in float (I am thinking that this may not have anything in relation to the trans problem).Problem #3: The parking brake indicator light is on on the EMS panel no matter when the switch is activated or not, although on the EPTC when I deactivate or activate the parking brake lever the EPTC shows that the parking brake is on or off. (Do not think this may have any relation to the trans.)Extra info: The EPTC does not show any faults in the transmission system, We have removed the drive shaft to the differential to be able to work on the truck more comfortably, We have replaced the up and down solenoids and replaced the transmission gear switch.
Submitted: 1 year ago.
Category: Construction and Road Equipment
Expert:  Dan replied 1 year ago.
Hi my name is***** will be glad to try to help. Test for power at the transmission solenoids in each gear position with the keyswitch on and thoroughly inspect the harness and connector pins for damage. This will verify if the shift controller is working and powering the solenoids. If ok check the solenoids for proper operation and do a click test powering the solenoids while checking for mechanical function removed from the transmission. Test the resistance of all to confirm all are within the same range of each other as well. To also confirm a bad solenoid you can swap to another location to see if the problem moves with it. Electronically the parking brake can effect the transmission from shifting but it would not allow any shifts if the controller sees the brake engaged. Also for insurance, check the transmission filter and suction screen for metal/debris indicating an internal failure occurring. Let me know
Customer: replied 1 year ago.
Hello thanks for responding. All of this has been checked prior to asking. Everything seemed to be within spec and clean.
Expert:  Dan replied 1 year ago.
Hi, Thanks for the update. So if all is in specs and all the transmission shift solenoids are powering in its selected gear as you said it was confirmed then the solenoids have been tested good too? But it will not shift and there is no indication of any burnt or discolored oil, debris or metal in the screen or filter? That is odd. Please give me some more information from the actual testing done ad the results so I can better assist
Expert:  Dan replied 1 year ago.
What did the solenoids OHM out at when tested with an OHM meter? How many volts are there to the solenoids in each gear position?
Customer: replied 1 year ago.
31.5 ohms-up solenoid
31.5 ohms-down solenoid
Up solenoid received 24V when i move shift lever to first but does not receive a 24 volt signal when I put it into any other gear. (I believe the EPTC is not sending the signal out to the up solenoid to move into a higher gear.) Also on the EPTC THERE are different modes to which I can select to further diagnose the trabsmission. In mode 4 (s gift monitor mode) it will show what I select on the lever and what solenoids activate when I do so. When I move the lever to selct gear 3 the up solenoid comes on for a brief moment (1 sec) and it shows the transmission shift into first, then i rais RPN and it will show the lock up clutch solenoid stay on but the up solenoid no longer comes on. After I put the lever into the neutral position the down solenoid will come on and stay on.
Customer: replied 1 year ago.
Shift monitor mode*
Customer: replied 1 year ago.
When I swap the up and down solenoids the transmission stay in gear 5
Expert:  catmastertech replied 1 year ago.
Hello, Dan has ask me to help you with this issue. I am assuming you have a service manual since you have the correct terminology for these components.I am not clear on a few things, if you will provide some extra details, it would be very helpful.You said the EPTC shows it is still in float even when you raise the bed? Is this correct?Have you tried disconnecting the hydraulic valve solenoids to see if they are causing the fuse to blow?Have you replace the parking brake switch? (The switch has two sections. One is for the light and one is to the control. Both need to work for proper operation.)Normal control of this transmission will default to the down solenoid being on and this is to force the transmission back to neutral when a problem occurs. If all systems are working correctly, one a gear is selected, the solenoids are not powered. a spring detent hold the valve in the correct position.Have you checked the shift control valve timing settings?Can you see the transmission output speed sensor working and increasing speed when you speed the engine with the transmission in gear?
Customer: replied 1 year ago.
No I have not tried disconecting the solenoids for the body hoist. I will try that tomorrow. I did connect 24 volts directly to the raise solenoid and the body did raise. on the TOS it maxes at 260 RPM in 1st. What are ways to check the shift control valve timing settings?
Expert:  catmastertech replied 1 year ago.
Here is the procedure to check the linkage adjustment.Verify the spring that hold the cam in position is not broken.
Customer: replied 1 year ago.
The spring that holds the cam in position is not broken. I want to confirm what engine needs to be in this truck. The engine has been replaced with a 3306PC and am not sure what is the correct engine for the truck. It maxes out at 2000 RPM and in the book the shift point charts do not match with the engine. I thought all 3306 engines max at 2100RPM.
Also I still need help with the fuse blowing on the body hoist switch.
Thanks for your help
Expert:  catmastertech replied 1 year ago.
You are correct. The engine speed must reach the correct speed or the transmission will not turn fast enough to shift. I am away from my PC so, I cannot get the spec at this time. I will get them for you tonight.
Customer: replied 1 year ago.
Okay thanks.
Expert:  catmastertech replied 1 year ago.
I just researched your engine spec's.The engine must turn 2400 at high idle for correct speeds.The original engine was 260 hp at 2200 but, top speed is 2400.Adjust governor to obtain at least 2400. Shift points are estimating engine speed must be at least 2350 to make the shift.TOS must see 287 rpm to shift to second speed. 491 for third, 817 for fourth and 1410 for fifth.
Customer: replied 1 year ago.
What would be the procedure to adjust the governor to raise the RPM?
Expert:  catmastertech replied 1 year ago.
Turn the high idle stop screw out.
Expert:  catmastertech replied 1 year ago.
Do you know which fuel system is on this engine?
Customer: replied 1 year ago.
Okay I will try adjusting the screw tomorrow when I am at the truck.
I know the fuel system is manual with a fuel injection pump that directs fuel to each injector.
Expert:  catmastertech replied 1 year ago.
Yes but, this engine had three different versions of fuel systems.Low pressure OLD SCROLL,Sleeve metering,High pressure NEW SCROLL.Each has different locations for the high idle screw.Serial number is ***** always correct.If you are not certain, upload a picture of the governor end of the fuel injection pump and I can identify it from the image.
Customer: replied 1 year ago.
Ok. I will not be able to upload a photo that til around 7 a.m. Central tomorrow.
Expert:  catmastertech replied 1 year ago.
Ok, I will get it by my phone and if it is not too difficult I will try to reply.I have some issue stay connected when I am out in the field.
Customer: replied 1 year ago.
Ok. I understand. Thank you.
Expert:  catmastertech replied 1 year ago.
I will be looking for your post. Thanks
Customer: replied 1 year ago.
Customer: replied 1 year ago.
I have attached a couple more photos
Expert:  catmastertech replied 1 year ago.
This is an OLD SCROLL (low pressure) system. However, it is not like the ones I have seen. It does not look the same as other engines. The next to last picture shows the end cover. This cover should have another cover on it where the idle screws are located.This could be a special governor and may not have adjustments. Try removing the rear cover and see if it has two adjusting screws at the top of the housing point rearward. The one to the outside is high idle stop screw. If you have time, when you remove the cover, take a picture inside the rear of the governor and maybe I can match it up to something else.
Customer: replied 1 year ago.
These are the photos with the back cover removed
Expert:  catmastertech replied 1 year ago.
I will need to do more research to see if this governor can be adjusted. It appears to be a power plant governor for pumps or generators. They are often limited in the adjustments available.Where did this engine come from? Is it a vehicular (machine) engine?I do not find a 49S prefix serial number but do see a 49V. Can you verify the serial number?
Customer: replied 1 year ago.
It came off of a generator bought at an auction. So probably makes sense why it can not be adjusted.
Expert:  catmastertech replied 1 year ago.
I am not having any luck locating a similar service manual for this engine. Can you verify the serial number?Have you tried adjusting the vertical screw. Back it out about one turn and see if the top speed changes.I am not sure this is an OLD SCROLL system. Can you get another picture of the whole fuel system?