My speedometer went out yesterday. The needle keeps up to about 20mph then drops off to zero. I checked out the cable, do not see any leaks or damage but while I was under I noticed a pretty good leak that appears to be coming from the top of the transmission either around the shift lever or possibly at the back of the transmission. Anyone seen this leak before? Could use some advice.



Hard to tell from this angle but it looks like it could be the gasket for the retainer plate (33599 in diagram below). If it is this gasket, could I replace it from the cab? I suppose it could also be from the back of the transmission and spun up from the driveshaft, but would have to be a lot of pressure to go up and forwards like that.

 

IMHO, Yes, it could very well be the part (gasket) you show. P/N 33599.
Also, yes, you should be able to change it out from the cab. You'll need to remove the shroud over the shifter first, the faux leather thing .Unscrew the shifter knob, and it should just slide up and off. I'm not sure how it's held down, but I think it's just some plastic tabs around the outside of it's frame. May be screws, but I had it in my pea brain you just need to slide a standard screwdriver under the frame piece, move it as far along as you can, until it get's stopped by one of the the clips, and give it a twist. Should pop right up. Get them all, and it comes right off. Assuming you took the knob off, that is.

Make sure that when you go to put the shifter back down in, presuming you removed it to change the gasket, which I'm pretty sure you need to do, everything is right back where it was when you removed it. IIRC the book specifies it should be in Neutral to remove/install the shifter. Once you get it back in, and bolted down, make certain it will actually place the tranny in the gear you think it's placing it in. Like you want to be sure it's not putting the tranny in 3rd when you think it's in first. That kind of thing.

Ensure the fluid level is correct, using the filler plug on the side of the transmission. It should JUST start dripping out the filler hole when the plug is removed, but as long as you can put your index finger in to the first knuck, the one right under the nail bed, and flex it down, you can touch the surface of the fluid.
Yes, you can add fluid from the shifter, while it's removed, but you still need to remove the filler plug to check the level. Keep in mind, you should always remove the filler plug before draining the transmission, or differentials, so you can be sure you can fill after you drain the old fluid. Nothing worse than draining the transmission, and then realizing the filler plug won't come out.

Does that help at all?
Pat☺

 

Yes very much! Thanks Pat. Ordered the parts this morning.