The Great Bronco Engine Transplant-UH OH!

For those not familiar with my blog, I write about a variety of my interests. One project that I blogged about between October 2010 and April 2011 was a project to replace the small V6 engine in my Bronco II with a larger 302 cubic inch V8 engine and automatic transmission. It culminated in this post: The Great Bronco Engine Transplant-Final Installment ,although I continued to post sporadically as I continued on this project. For those interested, if you go to the "Final Installment" and continue to older posts, much has been posted about this project.

Recently, I have been noticing the Bronco's transmission seemed to be leaking. I started preparing myself to remove the transmission and repair what was wrong. But I then noticed two more strange things, fluid seemed to be coming out of the transmission vent that I had mounted on the firewall and the fluid was dark in color instead of pink. This may have been the source of the leak. So, last week I disconnected the transmission hose that runs to the transmission fluid cooler in the radiator and anti freeze drained out. This was not good! There has to be a leak in the cooler. I looked at the antifreeze in the engine and sure enough, it looks like there is transmission fluid in the coolant.

So today I drained some transmission fluid out of the transmission. Fortunately,  I had installed a drain plug in the pan. The first fluid out was clear antifreeze/water before dark colored transmission fluid started coming out. I isolated the cooler and started the Bronco to warm up the transmission. After warming it up, I drained the transmission and torque converter(fortunately it also has a drain plug). Most of what came out looked like chocolate milk. After thoroughly draining, I refilled with nine quarts of new Type F transmission fluid. This is only for flushing. My plan is to change it out with another fill of new fluid followed by a filter change and the final fill of synthetic transmission fluid. Lots of transmission fluid will be used during this evolution. I am hoping that no permanent damage has been done to the transmission and the leak was actually fluid blowing out of the vent..

In addition to the flushing, I also need a new radiator. The current one is actually the second radiator since I changed engines. The first had a visible leak almost immediately and the company warrantied it. The current radiator is two years old. I have contacted the company to see if there is any warranty value left. If there is still a warranty, I will try to upgrade to an aluminum radiator that they also offer. If there is no warranty, another company offers the same aluminum radiator for a cheaper price. Either way, when I get a new radiator, I will need to flush the engine coolant too!

 Nine quarts of Type F transmission fluid standing by to give their lives to the flushing process.

 About a gallon and a half of chocolate milk colored transmission fluid drained from the torque converter. It should be pink in color.

The gallon of contaminated transmission fluid drained from the transmission pan. Notice the water/antifreeze mixture in the bottom.