Help with 82 Bronco again please

I thought I was in the short rows but I’m still having things to fix. Got the engine in, running good, but now the transmission. I was told it shifted fine when I bought the truck but I haven’t driven it until today. Reverse and drive, first, is good. It didn’t want to shift into second until I pushed it up into neutral and back down into drive. Went into second but that didn’t work for third. Ignorant me didn’t try to manually shift it. I didn’t do any work on it when I had it out other than filter, gasket, and fluid change.... any ideas?

The other problem is the temp gauge. I can dead short the gauge and it pegs out so I figure it’s good. Two sending units later and still no reading. Needle won’t move and I know it should. Previous owner had a set of aftermarket gauges on it but I rewired everything and have all other original gauges working right.

As usual, all of the advice and suggestions are greatly appreciated.

It is a c6 automatic and a 5.8

Danny, make sure you have bought a *sender* and not the *sensor*

Both have the same thread and connector.

I agree with Jim.  But you can test your units by connecting a DVM on the low resistance scale to one, place it in a small pan filled with water, and turn on the heat.  The reading should be of higher resistance than 72 ohms when the water is cold, and should then go to 10 or 12 ohms when the water approaches boiling.

On the transmission, make sure your shift linkage is stopping in the detents on the transmission for each gear.  If that's ok then there are a couple of other suggestions.  First, a bottle of Sea Foam transmission treatment worked for me.  Apparently things get gummed up when transmission sit, and something like Sea Foam helps clean the gum out.

And others have said that a quick blast in reverse helped theirs.  They got out where no one else would be, like maybe a parking lot after hours, and went backwards as fast as they could - safely.  

I would check the vacuum line going to the tranny.

grumpin wrote

I would check the vacuum line going to the tranny.

For fluid, meaning a blown modulator?

Or, for cracks?

Sorry, I'm a manual kinda guy, but I'm learning..

Vacuum is used to control shift points.

Had the line going down to the tranny get pulled off. First thing I noticed was it wasn’t shifting right, had the A/C on and then noticed it wouldn’t stay in the proper mode, coming out the defrost.

Finally the light bulb came on!