Hello all, We have a D8N (9TC03361) that is giving a bit of an issue. This one still has the pre emission 3406. Temp doesn't climb right away, you must work the machine 10-15 minutes, but if pushing in 2nd gear, the temp will climb and set off the trans temp light. If you grab 1st or 3rd, the temp comes right back down. This leads me to rule out the cooler. The machine does have fresh 30w trans oil, and I did cut open the filter and there wasn't anything in there that was alarming. Anything that comes to mind right away with a powershift transmission, when only one speed is creating a heating issue? I plan to run a full pressure test tomorrow to dig in a little further. Thanks much!
You said you cut the filter, did you find traces of anything that looks like fine grains of sand in it.? Another suggestion would be to remove the suction screen and inspect it at the same time.
The only thing that would cause heat only in one range would be slipping I would think run a pressure test see what pressures are in all ranges
I'd also be very interested to know why you push in 2nd gear with a tractor of that size.
Valid question. The operator who runs this machine uses 2nd gear too often. We have discussed this at length and we have that issue remedied. That still leaves me with a trans that is wounded. I cut open the filter that has been in the machine for a month now (since I cut the last filter, we needed to close out a job so the machine just came home), and there is indeed some metal in there now. Not a lot, but a few specs every pleat. Along with a spec or two of clutch material. I need to run P1, P2, a torque outlet yet (my 1k psi gauge got pegged this summer and I never had a chance to replace until this evening), but I have good main pump and good torque inlet pressure so far. I will finish in the morning and update. When I tested the machine yesterday, the transmission is still very strong in all gears. Pushes strong and will pull the engine down to stall in all gears. I've never been around a powershift that will overheat in only one gear so far. Looks like that streak has ended.
If the filter is seeing small amounts of metal & friction material I think you ought to find something more significant if you take a look at the suction screen.
I would comment that just because the Trans' filter has sparkle's it could well be from the R/Hand side Diff Steer gear train, the center gear has a washer welded each side to retain position, these washers can often get chopped up, I would still be looking at the coolers as it's worth checking and costs just a few gaskets. tctractors
Thanks all. Nige, I agree that I'd like to see what's in the screen too. I wanted to finish my pressure tests before losing that much oil. I was able to finish the pressure tests. All tests were spot on besides 2nd gear F & R. 2nd gear is 100psi lower than 1st and 3rd. Any ideas what could be the cause of the pressure drop in one gear besides potential clutch piston o-ring failure or valve body issues. I'd also like to get some ideas how to better isolate the pressure leakage. I'll be pulling the screen early this week to see what goodies rest in there.
Low pressure on the 2nd speed clutch is likely either a worn clutch with a piston overstroking or a piston seal on the point of failure IMO. Which one of the foregoing is the failure mode will probably be revealed when you pull the suction screen. I think you will find either signifcant amounts of friction material or possibly shavings of clutch piston seal in it. Question: Have you checked the speed cable adjustment.? Because you have good 1st & 3rd speeds it's not likely but might be worthwhile to check it simply to eliminate it as a possibility. Procedure attached.
Welcome to HEF, OwensExc !
Found the Teflon ring for 2nd gear rolled over. This must have been my pressure drop. Low pressure resulted in slipping and general carnage on the 2nd gear steel and clutch plates.
That seal was probably trapped and a sliver cut off the corner when it was first installed. You have to be really careful not to damage those seals when installing the clutch pistons. It’s really easy to shave a bit off the edge of the seal or get it twisted by forcing the piston into the housing.
Now that the Transmission is out, take a look at the center gear in the R/Hand steer hub , check the welded washer for cracks or damage, only the face that you can see tends to fail you don't have to strip anything down. tctractors