installed a 454bb in my Jeep CJ5. I used a TH350 transmision, but it has started making some form of rattling noice, when I start to drive. There is no noice, if I start veeeery slowly, but if I use just a little throttle, the 'case will say that awful noice. Any ideas to what my problem here is?

1. I'm betting on:[*]The Forward/Revers Clutch, or[*]the Torque Converter.

LEVE: You could be right! When I switch between drive and reverse, there's also a noice, which I don't like and haven't heard before. So yeah, the forward/reverse clutch is probably the problem. Can this be fixed when the transmission is still in the vehicle or do I have to take it out? Thanks for your help and very quick reply to my post!

1. Nope... unless it's a band problem.
2. The clutch is internal to the transmission.
3. Check the ATF fluid for clutch material, or
4. A burned smell...

Pulled the pan and in the bottom of it, lays alot of black, hard, small pieces. Don't think it's pieces of metal though. There's also a layer of black/grey thick fluid.

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lays alot of black, hard, small pieces. Don't think it's pieces of metal though. There's also a layer of black/grey thick fluid.

[/ QUOTE ]1. I'd bet the hard black material is parts of a seal, band or TC material.
2. Take a magnet and see if it magnetic.
3. The black/grey thick fluid is likely metallic gunk....
4. That's deposited on the bottom of the pan.
5. This is not good news.
6. IMHO... it's time to rebuild the transmission.
7. Do it yourself and save...
8. I've only rebuilt one TH350, and that was a bazillion years ago..
9. But it was easy... and didn't cost much for the parts.
10. Professional rebuilds won't be too much either,
11. If you drop and reinstall the transmission.
12. Just remember to clean the ATF cooler...
13. AND check for the warranty if you pull and re-install.
14. This may be a time to think about an upgraded AT...
15. A 455bb is mighty powerfull...

Thanks for all your help, LEVE. I'll pull the TH350 and get a professionel guy to rebuild it. I'm actually pretty good at working on manual transmissions and engines, but here in Denmark, it's rather difficult to get hold of a repair manual for the TH350. You woulnd't have to know, if there is some sort of online repair manual for the th350?

1. I remember seeing one several years ago,
2. But never captuerd the material..
3. I'll look around and see if I can find it...

That will be great! thx man

you may as well get a th400 or you'll be rebuilding it alot. i'v been through 3 th350's behind my 455 olds motor. they just are not built for big block torque unless it's just a big ol dog of a stock motor, even then it makes gobs of torque.
hope you have upgraded axles or they will be the next to go, well actually driveshafts first. and probably then the t-case if it's a nasty high hp motor. your motor has at least three times the torqu of even the biggest stock motor in that jeep.