I have a cat 950F serial 4DJ03786. It will shift into reverse, but not forward. I hear a slight change in sound when shifting to forward then again when shifting back to neutral, but no movement or gear engagement. Shifts fine into reverse.
It sounds like it has lost the forward direction clutch. Did this happen suddenly or has the engagement of FWD direction been getting slowly worse over time.? Another thought. Is the SERV CODE icon on the Monitor System display screen permanently lit.?
It happened suddenly, I don’t see any indicator lights.
This is an older machine that doesn’t have a monitor screen like new loaders
I’ve been told it may be the forward shift solenoid, I assume the solenoid is under the rectangular cover on the top side of the transmission, but I’m not sure how to access that unless you have arms several feet longer than mine, or raising the cab
You mean you don't have this............ Supposedly fitted on 4DJ-prefix machines from S/N 2685-Up, which would include yours.
Yes I have these just not the lcd display like newer machines. No indicator lights are present.
Look closely at the rectangular window in the lower part of the RH unit in the illustration. When you first turn on the key the self-test should be performed - all gauges sweep, warning lights flash, buzzer sounds, etc. You will see the SERV CODE indicator in the upper RH corner of that rectangular window. Above arrow 5. Question is does that indicator stay on or go off at the end of the self test.?
It must have bigger issues with the instrument cluster because it does not perform the self test. All of the characters in the lcd light and stay lit no gauge sweep no indicator flash
That's a shame, and something that needs fixing eventually. It amazes me that people can run machines with no warning system. Has any of that system ever worked.? Change of tack. Remove the transnmission oil dipstick and take a close look at the oil. Does it appear to be clear and bright or dark and cloudy.? Does it smell burned.?
I’m not sure if it ever worked, I’m new to this machine. The trans oil appears clean and clear and doesn’t smell
Is there a way to get to the shift “coils”? I was advised to swap the forward and reverse coil to see if the problem follows. The only place I can see that those might be located are under a rectangular cover on the top (left) side of the transmission. I do not see how to access this cover. I removed an access panel in the cab floor and I can see, but not reach the cover.
That is good news in that it suggests no clutches are burned. It is quite probably going to require the cab to be removed to get at the direction and speed coils. With no working onboard diagnostics I would be very reluctant to recommend simply swapping coils willy nilly with no real information to go on. My honest recommendation is to get hold of someone (doesn't have to be a dealer) who has Cat ET diagnostic software to hook up to the machine and tell you what the onboard diagnostics would be telling you if they were working. Otherwise you are working 100% blind with no information to go on.
Ok, thank you! I really appreciate the guidance.
When so much work is involved simply to access what may (or may not) be the problem in your shoes I would want to be in possession of some data-driven diagnostics before expending all that energy. There could possibly be a problem in the directonal shifter control mounted on the steering column, or a wiring issue between various electronic components for all you know. Hooking ET up would hopefully answer that question. Here is an image of the hydraulic control with the cover removed. The six solenoid valves are identified as follows:- Ref 8 - #3 (4th speed) clutch Ref 9 - #4 (3rd speed) clutch Ref 10 - #5 (2nd speed) clutch Ref 16 - #2 (Fwd direction) clutch Ref 17 - #6 (1st speed) clutch ref 18 - #1 (Rev direction) clutch.
Thank you for the diagram!
You’re welcome, but remember that a defective solenoid is only one of a number of possibilities that could explain your symptoms. If the valve was accessible I would say go for it - but it isn’t. That’s why you need diagnostic information first.