We had a somewhat similar episode recently with our ZF Meritor 12 speed transmission. As in your case it was not so much a transmission problem as an electrical one.
Driving the truck in snow and slop, we lost the automatic function on the transmission. It kept working fine, but we had to shift it manually.
Since we were passing through the area and had time, we went to our home Volvo dealer, the dealer that sold us the truck, VoMac Truck Sales in New Haven, IN, near Fort Wayne. These guys are fantastic and we get as much truck work done there as is practical to do.
The codes indicated a bad ABS sensor on a rear wheel. When one goes bad, the transmission is designed to go into manual mode, which it did.
A lesser mechanic would have replaced the sensor and sent us on our way. That did not happen. Our VoMac mechanic tested the sensor and found it to be good. He then went on to inspect the wiring and connections, and found a wire that had broken. The bad news was that it broke just where it led into a molded connector. To fix it right, the harness would have to be replaced. They did not have one in stock but could get one overnight.
That worked out perfect for us. I was on my way with the truck from home (MN) to Ohio for some training at FedEx Custom Critical. Diane was flying there to meet me, staying home for a dental appointment before that. After training, we were planning to drive to Milwaukee for a family event. A Saturday morning stop back at VoMac would be easily worked in.
I was surprised to learn that the little wire way in the back of the truck was part of a harness that reached all the way to the front. It was all one big and expensive piece (see photo) that would require three hours of labor to replace.
The good news was that with a 19 month old truck and 200,000+ miles, the repair was covered under warranty. Our VoMac friends believed the wire broke because of a manufacturing defect. Whoever put the harness on on the line, put just enough too much bend in the harness before he or she tied it into place. (Just enough too much bend... that's a technical term
).
A lesser dealer would not have gone to the trouble to convince Volvo of that and fight on our behalf to make this a warranty repair. We bought extended warranty coverage when we bought the truck. It was some of the best money we have ever spent.
By Saturday noon, we were on our way to a family event and into service after that.
With your Eaton issue, if it acts up again, it may turn out to be not the connections that were wise to clean, but a wire in the harness that may act up sometimes and sometimes not. Ours was an intermitent problem coincident with wet weather before the partially broken wire was diagnosed.
Let me close with a plug for VoMac Truck Sales. Again, these guys are great. Volvo extended warranty service has been fantastic too. It gives us great comfort to know we have five years of it in effect from the truck purchase date.
