Cat 416d will not move

Hello Guys,

I need help.

So I have an older Cat backhoe (416d with 4 on the floor 2000-2001) that hasn’t moved in a while. The engine starts runs great, all the implements and hydraulics function fine....BUT The transmission will not shift into forward or reverse.

After doing the the stuff listed below I’ve noticed the yoke intermittently make a quarter turn when shifted into forward then stop...other than that, I have no other movement going on. I feel like the oil is not getting to the clutches (oil level has not dropped since refilling the transmission)..or maybe there is some other electrical component I’m skipping over. Any help or ideas would be greatly appreciated.




Here is what I have done so far

-Tested the FNR Lever -ok
-Tested the Neutral Switch on dash -ok
-Checked and rechecked fuses -ok
-Tested voltage to Solenoids -ok
-Removed fwd and reverse solenoids, cleaned up, and bench test seem to be working ok.
-My next step was to remove drive solenoid valve block but found the Allen bolts corroded and stripped out looks like it’ll be a big deal to extract those.. So I backed away from that and removed the little spool valve out and inspect springs etc-some gunk was present, no scoring, cleaned up and put back together.
-Remove Neutral solenoid, cleaned up bench tested
-Drained trans oil, removed the screen filter at the bottom of the transmission. Oil was kinda black but nothing crazy in the screen
-Removed spin on filter, haven’t cut that open yet (only 200hrs old), replaced spin on filter and filled trans with fresh to4-30

2001 Cat 416d Backhoe
S/N cat0416de bfp02589

Thanks!
K

I think your next step is checking pressures, do you have stuff for that?

I do, I just didn’t have them with me at the time, nor did I honestly really an idea of what range I was looking for, this is very helpful thank you PE!

Ok today I checked pressure at all the above test ports warm at high idle and I have have zero pressure transmission. Initially I thought my gauge may have been acting up so I plugged it into the hydraulic pump to make sure it’s ok.

Is there a maybe a pressure relief valve or something I may be missing?

So the service manual i have for 416d has almost nothing transmission related in it that I can see. Did some digging around the web I found a transmission troubleshooting guide in a 416b manual. I know it’s a different transmission but I think the basic idea is the same.

Steps point to #15 inlet relief valve being stuck open. Does anyone else think this could be the issue?

I’m not exactly sure where it is located or if I can test it or remove it to inspect it, etc

transmission schematic

Hey thanks for that Mark!

...Forgive me if I’m interpreting this incorrectly, but If I’m getting near 0 psi reading at the pump check port (#1 on previous post) then it’s likely either the charge pump or something upstream from that is failing to provide the needed flow to the pump?

I think You should just pull the transfilter and crank it to see if the pump is able to pump anything at all
If you get flow then go ahead and check the relief.

Ok that makes sense...I’ll give that a go and see if I have any pump flow going on.

And thanks for the picture showing the relief valve all this is super helpful