I have a 1982 f150 4x4 with a straight 6, the transmission in it now is out of a 79 ford and its the one were the bellhousing bolts to the gearbox, well the threads were the 4 bolts go are striped and there's a gap between the gearbox and bellhousing. My question is should I just tap(make new threads) the bellhousing or get a new bellhousing or a new tranny all together? Any help would be greatly appreciated

 

I don't think a tap is going to fix the problem as it sounds like enough material is gone from the bell housing to prevent threads from being formed. And, a new transmission won't fix the bell housing. So it looks like you have three options:

1. Get a "new" bell housing that has good threads, possibly from the salvage
2. Repair the threads by using something like a Helicoil or having the holes welded up and re-tapped
3. Go "poor boy" and put nuts and lock washers on the inside of the bell housing. That will probably require you to bolt the tranny to the bell housing and then install the pair in one go, but that's the way the transmissions with integral bell housings are installed so shouldn't be a problem.

Having said all that, what has caused this problem? Have the bolts just been loose for years and finally stripped? Or, is there a problem with the transmission or drive shaft that is causing vibrations and, therefore, the bolts to back out?

 

If you drill & tap the bolt holes oversize it will work (I've had to do this on my bell housing - just the two bottom holes), - that also means drilling the holes in the trans slightly bigger too..........but as Gary said, re-tapping at the original size won't fix the problem.

 

Ken - Good idea. I thought about that but wasn't sure how hard it would be to drill the tranny oversize. Not too hard?

 

No, cast iron drills easily with a low speed drill.....a bit too easily sometimes. You can need to take the edge off the drill to avoid it pulling into the existing hole.

 

Thanks for all the info Gary, I just purchased this truck about 2 weeks ago to fix up and drive daily. I was looking up under there earlier today and noticed that my drive shaft is not straight it's at an angle so I called my buddy and asked him and he said that with the drive shaft being at angle could cause some kind of vibration and maybe could have caused the bolts to back out. So I'm thinking about getting a new bellhousing or finding a tranny for my year truck but not sure yet. Thanks for all the info guys this has helped me on my decision and also do any of you know we'er to get a bellhousing? I could go to a salvage yard but do you know of any websites were I could may e order one?

 

The drive shaft should be at an angle, so it may not be a problem. I have the spec's for an 81, and if your tranny is an NP435 and you have an NP208 transfer case then they'll work for you. But, you have to have a way to measure angles within 1˚ of accuracy.

I don't know where to buy a bell housing new. They don't normally go bad so most people get them from a salvage. What transmission do you have? If you don't know maybe you could post a picture so we can tell you.