A-727 Transmission noise

[CudaCraig]

A few months ago I picked up a '73 'Cuda with a fairly modified 440 in it with a TCI 727 with a reverse shift pattern.  The previous owner claimed it was cranking out ~550 hp on race gas.  I'm not sure about all that, but the car does pull like a bat out of hell in every gear.     Anyways, I've taken it out a few times on an abandoned road near my house and got on it as if i was running an 1/8 mi drag race.   After maybe 8 of these test runs I noticed the transmission seemed to slip and rev without the forward momentum expected.  No wheel spin either.  I got the car back home, but in the process noticed that the car now makes a rattling or almost grinding sound when it's in gear, 1st or reverse, moving and stopped.   There are no noises or idle problems with the car is in P or N.   I've tried it a few times since and the sound is still there.  What could that type of sound/behavior indicate? 

The car seems to have a stock stall torque converter, forward movement at ~1200 RPM, so my concern is that the tq converter couldn't handle the power and is failing.  Thoughts?   

[transman]

It is possible the converter is going away on you, but short of pulling it out and having it cut open, it's hard to say.
How is the oil in the transmission?  Are there any indications of contamination in the oil:  metal, clutch material, water etc.?  The oil should be a nice red color and not smell burnt.
With the transmission slipping, it is also possible you've got internal transmission problems.  Usually when a transmission is slipping, it's a good indication that the seals on the drums are going away on you bypassing oil and causing the friction plates to slip. 
If it was me, I'd start by dropping the oil pan and see what might or might not be in there.  If the pan has junk in it, and the filter is clogged, the unit should probably come out and taken apart to see what is wrong.  Burnt oil and crud in the pan/filter are signs of internal problems.

Just my  others may have another opinion.

[transman]

I forgot to put in my reply, that if the converter is a stock one as you think it is, for the HP quoted, it is definately not the right one.
transman

[CudaCraig]

It is possible the converter is going away on you, but short of pulling it out and having it cut open, it's hard to say.
How is the oil in the transmission?  Are there any indications of contamination in the oil:  metal, clutch material, water etc.?  The oil should be a nice red color and not smell burnt.
With the transmission slipping, it is also possible you've got internal transmission problems.  Usually when a transmission is slipping, it's a good indication that the seals on the drums are going away on you bypassing oil and causing the friction plates to slip. 
If it was me, I'd start by dropping the oil pan and see what might or might not be in there.  If the pan has junk in it, and the filter is clogged, the unit should probably come out and taken apart to see what is wrong.  Burnt oil and crud in the pan/filter are signs of internal problems.

Just my  others may have another opinion.

Thank you, Transman!  I drained a little tranny oil to see if there was any discoloration or particles and it does have metallic flakes in it.  I didn't see much if any clutch material, but then again I've been out of the game a while.   It is still red, but does have a slightly burnt smell to it.  No water.  I really appreciate the help/advice!     Sounds like she is going back up on the jackstands....    

Is there a torque converter you could reccommend?  ~550 hp, 727 tranny, 3.55 suregrip... I would prefer a TQ converter that didn't have a really high stall speed.  Maybe around 2000-2500(?) if possible?  Mainly because I don't know what RPM my engine can handle safely.  I know some of the competition and race converters have like 3000-4000+ rpm stall speeds. I generally only run my engine out to about 5000-5500 rpm.  If the problem is more than a new TQ converter, am i better off buying a new one?  Like TCIs super street fighter?  Or something else?

thanks again!

[transman]

Thank you, Transman!  I drained a little tranny oil to see if there was any discoloration or particles and it does have metallic flakes in it.  I didn't see much if any clutch material, but then again I've been out of the game a while.   It is still red, but does have a slightly burnt smell to it.  No water.  I really appreciate the help/advice!     Sounds like she is going back up on the jackstands....    

Is there a torque converter you could reccommend?  ~550 hp, 727 tranny, 3.55 suregrip... I would prefer a TQ converter that didn't have a really high stall speed.  Maybe around 2000-2500(?) if possible?  Mainly because I don't know what RPM my engine can handle safely.  I know some of the competition and race converters have like 3000-4000+ rpm stall speeds. I generally only run my engine out to about 5000-5500 rpm.  If the problem is more than a new TQ converter, am i better off buying a new one?  Like TCIs super street fighter?  Or something else?

thanks again!

PM sent

[blueironboy]

Sounds like a Torque converter - I just had mine go in a 97 Jeep with a 999.  I was researching like crazy to find the root problem of my Tranny failing and ended up finding some gems for info.  If it were a pump issue the noise would be persistent in all gears, as well as park and neutral.  Here's a great link that helped me out:
http://transmissioncenter.net/Transmission_Noise_Help.htm