I have been on a quest for a carburetor in my area for the past couple months and I have just gotten one recently for the 76' bronco in question. I believe this will finally make the engine run stably as it has been recently rebuilt and tested on a similar 351w motor. However, during my time of searching, it seems that another problem has developed. The C4 transmission in the truck seems to be leaking transmission fluid while the truck has sat. I had filled it up when we had the truck running previously to move the truck around, but while it has been sitting waiting on the new carburetor it appears all the fluid has escaped. As all the undercarriage is thoroughly coated in grime and other oily fluids, it is nearly impossible to tell exactly where the fluid is coming from. I am tempted to think it is the gasket on the transmission oil pan, but I am honestly not sure. If anyone has had a scenario similar to this I would be interested in knowing your solution. Thanks in advance.

 

You're probably going to need to steam clean or pressure wash the underside of it before you try to diagnose where the leak is coming from if it is that dirty.

Jason

 

Being that the Bronco C4 is a pan fill with dipstick in side of pan, that would be a good place to look. After setting for awhile, the torque converter will drain back into the pan too, really emptying it. I can imagine the mess. Any other place leaking would still show some fluid on dipstick.

 

unless U can C the color, or smell the difference I would not assume it's tranny fluid. Have U checked the crankcase as well? I like the "clean it all off" idea too. At that point U could put a newspaper of something under to spot the worse of the leak. Then trace that up (due to gravety). A stream down the block somewhere will lead upwards to the leak. I found a head gasket leak this way (all the way up to top of motor). Could see the stain after clean up, then the H2O as it leaked.
Couppla spray cans of that stuff, garden hose, long handeled scrub brush? Drive in quarters-as-U-go sprayer, rented/barrowed steamer? Lotsa ways just cover carb & ele parts. Let us know any Qs.

 

I am actually sure this is transmission fluid. It has always had a minor leak that I have never known where it was coming from. however, it would hold pressure as long as the engine was ran every few days. this time it has completely dumped the fluid more or less. Would this suggest the idea that the torque converter drained into the pan and possibly leaked there? I completely agree that I need to clean it up to further suggest this but I am more or less just looking for a place to start.

 

My son's Mustang was leaking around the dipstick base(case fill). It too would only leak slightly if run every other day or so. Once it set long enough for the torque converter to drain back, same deal, large puddle. So yes, pan gasket is a good place to start. And agree, really need to clean it up. Shifter shaft, band adjuster, vacuum modulator, cooler lines, all good leak sources.

 

sometimes the fan &/or just drivin (the 'wind' generated) blow it back too.
1) clean, 2) may B sompin under (newspaper?) to find leak fast (might indicate sm leak quicker) 3) if needed - a re-fill up of fluid for a bigger indication of where it is.
Good Luck, keep talkin

 

Okay, so I seemed to have developed yet another problem. I was trying to get the engine to start after installing the new carburetor. The Carb works flawlessly, however, the engine will not start for anything. The voltage at the positive side of the coil is 12.4v when not cranking and about 9.3v under cranking load. Is this normal? If so would that mean that I have a bad coil? The truck has the Duraspark Electronic ignition. I am not ruling out one of the wires being shorted because that is a possibility, but the last time I started it with the bad carb it ran fine. Any ideas?

 

Are you getting spark? 9.3 volts is a bit on the low side. But if you've ran your battery down trying to get it to start, your static voltage might show fine, but under load it is dropping. Is it cranking normally?

A Duraspark module can fail like that. Running one day, nothing the next. So don't rule that out.

Jason

 

it hesitates to crank at first but once its going its normal. The battery is fresh off the battery charger because I figured that could be a problem. But I know it's a good battery as its from another one of my trucks. And I don't really have any idea whether or not its getting spark as I'm not really sure of a safe way to test that? I know it has fuel so I can only assume it doesn't have spark. Assuming the duraspark module is bad what would be the most effective cheap solution? Should I just look for one at a junk yard or would I be better off to get one from an auto parts store?