Hi everyone!

Thanks for all the good info! I had asked my mechanic about welding that used one with the small crack & he said he didn't recommend it & wouldn't do it. My parts guy found one that was supposed to be new but when it arrived it was of course used (not to mention overpriced) but thankfully not cracked. It took what seemed like forever to get it (it finally arrived yesterday) & my mechanic put the new exhaust manifold, used intake manifold, new intake gasket set & new carb base gasket set in it & now his engine is so quiet that it's freaking me out, lol. It's crazy how quiet he is! He even feels different when I drive him, smoother than before - is that common or unusual after this kind of repair? I took pix of the damaged parts & boy, my mechanic wasn't kidding when he said it looked like something exploded in there . I'll post the PhotoBucket link in this thread once I've uploaded them.

During this whole exhaust leak escapade, we discovered that the transmission module is leaking & needs to be replaced. I'd asked my mechanic to change the transmission oil & filter while my truck was in the shop but for some reason he didn't do it. He said the fluid was really low today so he topped it off but it felt like it was stuck in first gear. He was shifting just fine when I dropped him off so I had no idea what could've happened. Apparently a vacuum hose was loosened during the manifold replacement & when he got under the truck to check it out, he discovered the module was leaking & sucking up all the oil. He's ordering the new module & I'll take my truck back as soon as he gets it. Napa Auto has a wide variety of transmission modules (& for a great price) but I don't know if I need a C5 or C6 module. Their parts guy said I should bring in the old one to compare; I'm sure my mechanic will know & I'm hoping he can get the part tomorrow morning so I can get that fixed ASAP. A friend of mine told me not to drive it anywhere till I can get it fixed or I'll ruin the catalytic converter w/all that oil & I risk ruining the transmission. It's been leaking for a while unbeknownst to me so now I'm kind of worried. Even the parts guy said, "Gee, I hope it didn't ruin the transmission." Thanks a lot, guy! Sheesh! How would I know if the transmission is ruined? Like I said, he drives fine & nothing seemed unusual other than the loud former exhaust leak, which I was well aware of. I didn't even know I had that problem till today. You guys probably think I'm a total weirdo & I admit I am a bit weird but I don't have anyone mechanically inclined out here to help me out (other than my mechanic & of course that comes at a price) so any advice you guys can give me will be greatly appreciated!

Thanks so much as always! Have a great rest of the week!

 

I don't see how transmission fluid leaking could wreck a catalytic converter? Maybe he thought your motor was burning oil. A motor that burns oil will ruin a cat, but unless the transmission fluid somehow gets into the converter I don't see how it could hurt it.

You can drive the vehicle, but you need to do so very sparingly and be aware of how much fluid is in there. Low transmission fluid can burn up a transmission like low oil burns up a motor. Except with a burnt up transmission you won't be able to go anywhere.

Get your transmission leaks fixed, and drive, drive, drive! You should notice it'll have a lot more power when you drive it now, and accelerate REAL smooth. That's the power of the mighty 300.

If you ever have a problem with the truck itself, feel free to visit us over in the 80 to 86 forum.

 

Thanks! I was really freaked out when he said that - I had big plans to drive my truck around this weekend but now that's all on hold till I get that module replaced. I check the oil myself periodically between oil changes & he's never been below the low line (I even know how to check it the right way, lol) but as far as the transmission fluid goes, he's never needed too much topped off during regular oil changes till recently. I wanted my mechanic to do a full transmission change because I thought the filter must've been bad after the last time I got my oil changed (2/7) when they said it was pretty low. My truck had been shifting just fine even with the low transmission fluid. (Btw, how does one check the transmission fluid on a regular basis?) Since he's still shifting normally, would you say his transmission is probably still okay?

Once I get that module replaced, I definitely plan on driving, driving, driving! I've got to run a bottle of Guarantee 2 Pass with a full tank of gas through it before I get him smogged & I have places to go soon!

 

just saw your thread. i have just finished my own experience with the "manifold hell." first, the intake CAN INDEED crack. when i pulled mine doing a head job, it was cracked. the exhaust was fine. i had a friend weld it, but then he ground off a "blob" and in the process ruined the mating surface between the intake and exhaust.

i went to a local salvage, got a complete new unit for $25. when i saw that the two sections were NOT flat, i separated them. i should note that when each unit was separated, the two long bolts snapped off in the exhaust manifold. i drilled and tapped the old exhaust manifold, installed the new unit, and it worked fine.

unfortunately, the lower end of my engine was just as worn out as the head (i had blown a gasket), so i ended up having to re-do the bottom end because of excessive blow-by. when i went to re-install the manifolds, it was dark outside and i unknowingly broke the ears off of the intake manifold.

went back to the salvage, got another complete unit. the junkman told me not to separate the two, as you can end up asking for trouble. well, since i had done the first one succesfully, i ignored that advice and put together the new intake with the best looking exhaust. only problem was, it leaked where they join together. upon inspection, the castings were just different enough that even with the new gasket, i just couldn't stop the leak.

i then put the "new" intake back with the "new" exhaust, got new nuts b/c i could NOT remove the studs, put it back together, and.... IT WORKS.

when these engines were a lot newer (about 15 or so years ago), my brother-in-law took his in for repair and was told that a new unit from ford was going to run him $700. he sold the van. these parts are starting to get scarce, and i don't know what the future may hold. where i live, i can go with an aftermarket intake and EFI manifolds, but we don't have smog inspections. also, i don't want to change to a 4 bbl carb at this time. fortunately, i don't have to. the truck is for my 17 year old son, and the stock freshly rebuilt engine has quite enough power for him, thank you very much. ours is also an 86 f150 4X2.

good luck with your truck!

 

If the diaphragm in the transmission vacuum modulator tears, then your transmission fluid will be sucked through the vacuum line into the intake manifold. I think that is what your mechanic is worried about. It probably can damage the catalytic converter if it goes on for a while. It will also screw up your shifts and make them late - for example, it will stay in 1st gear way too long, etc.

I wouldn't panic over the cat yet. Let him replace the vacuum modulator and top off the trans fluid. Then see how everything works. If your exhaust still smells like "catalytic converter exhaust" (a very mild smell with just a hint of "rotten egg") it is probably ok. If the exhaust has that old "just like my dad's 1965 station wagon" smell, the cat is probably toast.

 

Hi everyone,

Sorry for the totally late update. I wish I had better news. After I got the intake & exhaust manifolds fixed, my truck sounded so quiet that I sometimes didn't realize he was running, lol. I took him to be smogged but he failed due to running too rich Since he's the last year of carbs in the F-series, hardly anyone works on carbs anymore & it costs a heck of a lot even to simply diagnose it. I was unemployed & couldn't afford it so I paid my DMV fees & rarely drove in an effort to avoid getting a ticket. Paying the DMV fees does not mean your truck is registered as I just found out & I got in major hot water for that & now need to get him fixed ASAP. I really thought fixing the intake/exhaust leaks would do the trick but the test shows carb issues I've had to have the carb rebuilt at least twice before so it looks like I'll be doing that again. My regular mechanic isn't "STAR certified" so he can't repair my truck & certify him all at once, he can do the repairs & then I'll need to take him to a STAR station to be smogged. I found a STAR station that can repair & certify but they don't do carbs. He said I probably need a new catalytic converter, too, which they can do. So I've got to get the carb rebuilt (maybe just adjusted if I'm lucky) & then do a cat test & most likely replace the cat. I'm going to start another thread regarding the carb & cat issues to see what others have experienced. Thanks for reading. Have a great weekend!

 

Hard to believe youve had this carb rebuilt twice and a third rebuild would solve the problem.
Is this possible a feedback carb running in limp mode ? That would explain why its running too rich. ?

 

I looked back through my records & the carb has been rebuilt 3 times - isn't that nuts?!?! I took my truck to a carb specialist who adjusted it quite a bit (it was cool watching him work) & at first he got it running too lean but then he got it just right & the #s were in the passing range. It's now at the STAR station to get the catalytic converter taken care of. The carb specialist said the rear cat was shot but there's a chance the front one might be okay; I'm not sure how he knew about the rear cat but he seems like a very honest guy & I was thrilled that he was able to get the levels in check for a $100 adjustment vs. an almost $400 rebuild. I also can't believe that I've had to have the carb rebuilt so many times. I think I mentioned this earlier, but I had to replace the block back in 2003 'cuz the original cracked when he overheated & he's failed smog ever since Past mechanics have said it's just a coincidence but it sure doesn't seem like a coincidence. Wish me luck on the cat work - I'm praying they fix it for a fair price & then smog & certify my baby so I'll be legal again!

 

Is it possible a smog pump attached to a faulty cat could cause the computer to run in limp mode. I would think so but not sure.
Is this a feedback carb or not ?

 

Guys, look under her name. Right below "Catherine M" it says, "1986 F150". It's a feedback carburetor.

Pardon me for saying this, and I don't mean offense to you when I say it, but all of your mechanics sound like a bunch of ignorant morons.

Really, it sounds like they've all been milking you along and digging money out of you with a shovel. This horse crap has just been flat ridiculous.

To start with, rebuilding a Carter YFA isn't rocket science. It's pretty much the simplest carburetor out there. YOU could do it with a cheap GP Sorensen rebuild kit. Tuning the carburetor? Hah. 20 seconds with a vacuum gauge, then set the idle speed screws and you're done. That's for the old non-feedback models. Yours should be computer controlled. If there's anything wrong with the motor, they can pull codes.

I could understand replacing the catalytic converter(s) if the truck didn't pass smog. But that's AFTER verifying the carburetor is adjusted right, the timing is set right, the ignition has new plugs, cap, rotor, and wires, the filters are all good, the EGR is working right, the smog pump is right, etc. For what it's worth, if you have to replace one converter, replace BOTH. Don't replace the one and leave the old one on there. Decent converters can be had for CHEAP from RockAuto or Summit. I got mine from Summit Racing for a little over $100.

These mechanics all sound like parts changers to me... Just my $0.02.