I have a 79 F-250 that I swapped a freshly rebuilt 460 into about 3 years ago. Since my truck already had the big block c6 in it i reused the trans without anything but a new filter and fluid. I bought motor mounts and retained the stock tranny mount. I ran the truck this way for 2.5 years doing a mix off on and off-road driving totally about 2500 miles on the original tranny the truck rolled of the assy line with back in 1979.

Here is where my problem starts - Last June my stock C6 finally decided it had had enough abuse from the 460 and gave out. Not a huge deal I knew it was a matter of "when" it went not "if" it was going to go. So after saving up for a couple months I bought a bunch of internal goodies for the rebuild. I then took it to a local transmission repair shop in my area to have the trans rebuilt with the parts I supplied them, which were all high-end brand-named components. I got the trans back in about a week all ready to go. I installed it very carefully making sure to line up the torque converter into the pump drive gear before putting the trans under the truck. Everything went together great and worked fine for about 2 months. (which only amounted to about 10 miles of driving but about 3 hours of running.)

All of the sudden a couple days ago my truck wouldn't move anymore after shutting it off at a gas station. Called trans shop who said it sounds like the oil pump went out. So I got towed home and pulled the tranny out. I found the the pump plate bushing had welded itself to the torque converter. I brought the whole trans and torque converter to the shop that worked on it before. Upon disassembly they found that the oil pump gear had ground in to the pump which caused it not to move fluid anymore. Upon further take down the tech found that the hub that encases the planetary gear set had a dent in the back of it(side that faces the rear of the trans) that was round with a 4 square box inside of it. He cannot figure out what hit the hub as every component thus far in the trans had been in the correct place.

Does anyone have any idea what may have caused my problem???

I know for a fact that the torque converter was fully seated into the pump gear and I had to pull the torque converter about 1/8 to 3/16ths of an inch forward to get it to contact the flexplate properly. It had the correct amount of fluid in it as well as the right fluid type.

Please help so I don't hosed for rebuilding my trans again from their possible mistake. Or please help to figure out what I may have done wrong on my install.

Thanks.

 

Other than putting the converter all the way on (mine usually take a spinning after they first go on, then they drop back one last time), there is really no rocket science to it.
The problems with farming out your rebuild is just what you describe; You don't know that the tech didn't do something wrong, and he doesn't know that you installed it right. Also, the parts were yours, so you have to chase down the warranty.
The trans tech should be able to tell you what happened in there. That dent sounds like a strange occurrence ... Maybe take it to another shop for their evaluation?
How much did you pay for the overhaul? I have paid about $300 for my C6's, plus $100 for a shift kit each time. (I bring them in myself)

 

I payed 200 for them to rebuild it but I had about 1000 in parts including a new converter. I plan on bringing it to another shop tomorrow after I pick it up today, I want someone to look at the parts that came out of it and give me an honest non-bias answer. I am relatively certain that it wasn't my mistake as I have installed a transmission 4 times with no problems until now.


When I brought it in this time they first told me the converter was out too far and not engaged in the gear. Then after they pulled to pump cover they changed their story and sayed it must have been in too far. After they told me that I then explained to them that I had to pull the converter forward some to get it bolted up. Then they switched the e story to the line pressure being too high causing high force on the front of the pump gear. This is the only thing that I cannot verify, but I will check when I re-install it. The pump gear could be the result of too high line pressure but I am sure that high pressure doesn't put dents into internal steel components.

 

Sounds funny to me too... Increased line pressure is what most kits do anyway, and every trans I had rebuilt was done that way with no troubles... Never had to replace a rebuilt trans before, as they seem to last forever.

 

The company I got my parts from it www.broaderperformance.com , and he is quite well-known and very knowledgable with Ford transmissions. I don't think he would have sold me something that would cause extremely high oil pressure without letting me know what to do to avoid it. I got all the internals from him except the sunnex "R"-code band apply servo. I picked up the 500hp rebuilt kit from the site and added the revervse manual valve body, 5 - clutch direct drum, and the stepped pressure plate for low/rev clutches. All the parts are high quality that broader performances bases their reputation on. He also hand built me a 1800 rpm torque converter to work with the manual V/B. I was really hoping to have to never pulling this tranny again after the first rebuild, so you can imagine I wasn't very happy to have to pull it again, this time in the michigan winter weather.

I will post pics of the internal damage when I actually get everything back.

 

Dang, that sucks even MORE with good parts like that gone to waste! I doubt you did anything wrong. Other than seating the converter fully, the job is quite straight forward on these things... Did it shift decent before this happened? How was your vacuum at the modulator from the vacuum line? I had a new rebuild that started acting up shortly after installation, and found the steel vacuum line kinked, restricting vacuum.

 

It shifted just fine before this happened, but I have the manual valve body so I no longer have any vacuum hooked to my trans. The modulator hole is now blocked off.

 

Oh... Duh! lol
I guess I should read a little more before posting haha...
Let us know what another shop says if you can get another opinion.

 

I will keep you up to date with what I find. I even went as far as to buy a new flexplate, mostly because the ring gear on mine was a little rough, but also because the trans shop thought it wasn't the right one for my set-up. It did end up being the correct one that I had but the new one has a solid center instead of the cut-outs the ford one had so it should be stronger.

I will post pics of the stuff sometime thurs night or friday morning after I pick it up thursday afternoon.

Thanks

 

to maybe make ya feel better....I had a rebuilt C6 going back into my bronco when the tranny slipped off the jack, nose dived, and cracked the aluminum case from the starter bolt all the way to the other side, pushing it upward about 1".

 

That sucks, I had mine slip a couple times when I put it in after It was rebuilt the first time but not hard enough to damage anything. After that I went out and picked up a motorcyle/atv lift. There are about $90 at most places and work slick because they have a wide base that lifts without tilting.

What did you do about a new case, or did you try having yours welded?

 

It's sitting out back. My truck currently has a NP435. It originally had a C6. I thought of putting a C6 back in until that happened. I have another case, but am in no hurry. I swapped a 300 and small block C6 into the bronco instead.

 

Well, I have everything back in my possession now and the trans shop that I had it at still didn't have any new ideas as to what happened. The did find out the the converter I was using either got damaged in the carnage or caused the carnage, and now the pump gear won't slide onto the hub at all. So I got a price on a new converter from them ($210) and then called the guy who built the converter for me. After an hour on the phone with him and without him seeing the parts he basically diagnosed the root cause of my problem. From what I told him I had experienced he is pretty sure that my pump for some reason wasn't getting fluid to it and was cavitating. He also gave me some pointers of things to check when I re-install everything and fire the truck up. He is also going to go through my converter again and check/replace the stuff that got damaged. He said he has had a few before that he did all the work on that have done this to him but he has a dyno to run them on with a pressure guage hooked to the trans so he knows there isn't any pressure and shuts it down before any damage is done. I wasn't so lucky this time.

The guys at the local shop also helped me out a great deal by only charging me $50 for this complete teardown and build up. Which I don't think even covered the gaskets, seals, and forward clutch plates that they put into it. Plus the even pulled my other parts tranny down and installed that pump into my good trans.