Overfilled Transmission, Broken Wires

A second-generation Honda Insight came into the shop with a complaint of low power when accelerating, and the transmission “D” indicator was flashing. When I pulled it in, it was clearly something going wrong with the transmission.

I went to check the fluid, and when I pulled the dipstick, I could see the fluid in the dipstick tube. Normally you should not be able to see it, it should be only up to the bottom of the dipstick, which in this case in a few inches long. Because there was so much fluid, it was leaking out and the entire transmission was covered.

When I drained the fluid, I tried to measure how much came out, and there was at least two gallons, when it’s only supposed to have three quarts. My only guess is that when the “D” light started flashing because of a bad sensor wire, the customer or someone they know thought that it must be low on fluid so they just filled it up until they could see it, which is exactly what you should never do with engine and transmissions.

After fixing the fluid issue, I got to fixing the actual cause of the transmission problem, which was broken wires leading to the input shaft speed sensor. Normally, the best way to fix broken wires, especially ones attached to a sensor, is to replace the entire harness. The customer couldn’t afford that, so I had to repair it.

I found an identical connector on an old harness lying around the shop, and used shrink tube butt connectors to attach onto the harness. If I’d had the space, I would’ve staggered where the wire splices were so it wouldn’t be a giant bulge with all three side by side, but there wasn’t much wire to work with on the harness, and not a lot of room to work.

I got all the wires hooked up, checked that it worked fine, and then wrapped the wires up in plastic loom and electrical tape. It was a lot longer than the original harness, but fit in the area just fine.

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