I have a 2004 420d cat backhoe that is not going into forward properly. it works fine in reverse but when I put the transmission selector in forward it doesn't move. it will move after some time idling. any suggestions on what the problem is??
serial number please is this a manual box with forward and reverse shuttle or auto shift? Mark
I had a similar problem with my '02 420DIT except it wouldn't go in reverse. I replaced the FNR selector and it fixed it. The selector is a sealed unit, plug and play. Here's is the thread on my fix - HeavyEquipmentForums That fixed my problem , yours may be something different. Mine would not move at all but after cycling the selector I could get it to go in forward or reverse, whichever was acting up at the time. Best of luck.
Ditto what CM1995 said on His 420D... my 420DIT required the same replacement.... I think the price was around a hundred bucks.
serial # bln10735.It's a semi -shift with 4 gears with fnr selector and no clutch
Hi crocker14, has this problem happened slowly over time or suddenly? have there been any repairs done on the transmission or electrical repairs to harnesses etc. what is the condition of the transmission oil. has it been serviced recently? what grade of oil are you using? a couple of things to check.to make these checks easier, remove the floor in front of the seat. 1/check your oil level 2/cut open transmission filter and inspect for contamination 3/remove transmission suction screen from transmission and inspect for contamination if these are OK 1/check voltage supply to forward solenoid with shift lever in the forward direction .should be battery voltage approximately .if low you need to trouble shoot electrical system if ok proceed with next step 2/swap solenoid from revers clutch to forward clutch position and try if no change proceed with next step 3/install pressure gauges in pump test port on top of transmission and also install pressure gauge to forward clutch test port also on top of transmission pump pressure at high idle should be about 220 PSI forward clutch pressure at idle should be about 205 PSI if you can not obtain pump pressure you have an internal leak inside the transmission or a week transmission pump if your forward clutch pressure is low and your pump pressure is OK. it is possible that the forward control valve is sticky or faulty or internal leaks in the clutch pack or shaft seals if you need the test procedure please let us know Mark
This is an old thread, but we have an old machine, so our issue seems to fit here. In our case, we have an FDP-series CAT 420D that has trouble shuttle-shifting into Reverse. As the reverse alarm comes on each and every time the shuttle control is shifted into reverse, I removed the floor plate and took a look at the Shuttle Control Valve Group (SCVG) on top of the transmission. After reading this thread, it would seem that that the two solenoids in the valve body can be swapped as a way to troubleshoot the issue...but my inspection revealed that each solenoid has a final connection "block" with different shapes. As this usually indicates a way to prevent "cross wiring," I'm now wondering if the two solenoids may be different? I also noticed that the Reverse solenoid is being held onto the valve body via a hex nut with a notch milled into it. On the other hand, the Forward solenoid is held in place with a normal hex nut. Any thoughts on this would be greatly appreciated. Thank you for your time ~ HL
cat 428c .I have a problem with the front rear handle, when I install a new one it plays in reverse