Man, this is a real head-scratcher. I can't wait to find out what the actual problem is, the suspense is killing me.

I am beginning to wonder if it's not something really weird, like something that is wired incorrectly. Like, maybe the switch that won't let your car start in gear is killing the engine when you put it in gear, or something crazy like that. Keep at it, you'll get it, sooner or later.

Scott

 

Probably nothing really exotic. That video was very enlightening. Been barking up the wrong tree with the timing thing. But it's all good in the end if we find the problem. And now the timing is better too.

 

I'm racked with anticipation myself. I am so close to being able to finally drive this thing and this "little" problem is just killing me. Just hope to get it figured out before the first snow falls. Anyway, I will get it up on jack stands tomorrow and do some more. I am running a marathon next month to raise money for Leukemia research and my 16 mile run this morning has dampened my motivation. I'll let you know what happens tomorrow.

 

16 miles, yeah that would do it for me for a day. Looking forward to the results.

 

I have a friend who runs the Boston marathon every year, and I'll tell you the same thing I tell him: Run 26 miles? Dude, I complain if I have to drive my car 26 miles. That's a long drive!

Scott

 

Yeah, it takes its toll on you. I bought this car as a project for me and my dad, but he passed away a few years ago. He was pretty young when he died (65) and I figured I should do something so I can stick around a little longer for my two girls. Plus, I get to help raise money for blood cancer research, which is a plus.

Anyway, got the car up on jack stands, started it up, let it warm up, then dropped it in gear. Let off of the brake and she ran like a top. Applied some brake, and as the rpms slowed to near stop I could feel a stall coming on. Shifted into neutral, no problems, into Drive, ran fine as long as the wheels were moving. Once I applied enough brake to nearly stop the wheels, again, almost stalled. So what do you guys think? Torque converter? God I hope not. I do not relish the thought of taking the transmission back out.

Thanks,
Bryan

 

There is only one thing between the engine and the transmission. I'd say you have a torque converter problem. Maybe it's just not installed properly. Three bolts connect it to the flex plate. Did it bolt up easily or was it jammed in tight against the flex plate?
You may be able to disconnect the drive line, bell housing, and trannie mount then support it with blocks, slide it back a bit and tip the bell housing side down to slide the converter off. Still plenty of work but not muscling the trannie around as much.
When I replaced my trannie, I put each tire on 4 concrete blocks, 2x2 so it was two blocks high. This gave me enough room to maneuver around under there.
If new torque converter is needed then I would get a higher stall converter maybe 2400 rpm or so.

 

I am going to go out on a limb here and say that your problem is definitely somewhere between the engine and the wheels.

A friend of mine is convinced that an automatic transmission "has a twinkling of magic in it", and I can't find any reason to tell him he is wrong about that. In fact, if you wrote a book called "What scottyp99 doesn't know about automatic transmissions", it would probably be an extremely informative book about automatic transmissions. In other words, we are out of my comfort zone here, and you are on your own. My suggestion is to get in touch with whoever re-built the tranny and tell them what is going on. I will go out on a limb with a guess, though. I think the torque converter is spinning whenever the engine is running, and when you put it in gear, the transmission is connected to the torque converter. The engine should stay running because of the slip that is provided by the torque converter, but if the torque converter isn't slipping, it will be just like a manual transmission in gear, and stall. I have heard several people describe it as such when using a switch to manually engage and disengage the lock up on a 700r4 transmission. If they forget to disengage the lock up, the car stalls when you come to a stop. Long story short, yeah, I'm guessing it's the torque converter.

Scott

 

It was installed correctly. I was very careful to make sure that it was. I installed the engine and transmission as one unit. When I mated the two, I had about 1/2 inch clearance between the TC and flexplate. I guess it must be the TC but based upon my understanding of how the TC works, I just don't see how it could be locking up. Guess I'm getting the transmission jack out of storage. Damn. Appreciate all of the help from you and Scottyp99. At a minimum, got the time dialed in and my distributor recurved.



Bryan

 

I don't know how it could be frozen up either. All the evidence seems to point to that. I haven't been able to find any other instances of this kind of failure. Maybe it is an exotic failure? Is this the same torque converter you started with or is it new?
If you end up replacing the torque converter here is a little info on them that I found.

http://forums.corvetteforum.com/newr...1&p=1584875168

 

It is a replacement TC but I am not sure what the stall speed is. I had the transmission rebuilt long before I had the motor done and upgraded. I suspect that the TC is closer to stock stall speed than not. I did some reading on a few other car forums and found some discussions of like problems with upgraded engines and stock stall speed TCs. What's more, on Jegs website, they recommend a 2200+ stall TC for an engine similar to mine (cam specs, comp ratio etc). I can't say that I understand the reason for this, but just because I don't understand doesn't mean that it isn't the answer to my problem.

 

A higher stall torque converter allows the engine to get up to an rpm that the cam operates in easier. This gives it a much better launch capability. A higher stall allows it idle easier since the cam will not want to idle as low as a stock cam. Also while stopping and at a stop the engine is not fighting the brakes so much since the torque converter is a "looser" allowing more slip below the stall rpm.

Highly recommended with a higher stall torque converter is an additional trans cooler. Since there is more "slip" in the fluid coupling of the torque converter more heat is generated. Heat is the enemy of the transmission.
Now the bad news,... Since you may have a torque converter failure it's possible it made metal and circulated it through the transmission.
If it were me I would want to find out why and how that torque converter failed. Than means having a transmission shop open it up and inspecting it. If all the parts are there and no metal appears to be missing you may be all right. Give a reputable transmission rebuild shop a call and ask some questions about Converter failures and if they have the ability to open up a converter or what they would recommend. These guys do it for a living, we are just amateurs. Their input would be good to consider your options.

 

I decided to take my own advice and called a transmission shop, a guy I trust. His belief is that there is something wrong with the transmission not the torque converter.
He says if the torque converter was locked up that the engine would be loaded even in park. So since that is not your situation then it looks like you still have a transmission problem.
I guess you may have to go back to the shop where the transmission was rebuilt and tell them your story and see if you can get them to stand behind it.
Yep, were amateurs. In either case the transmission is coming out.
When I replaced my transmission I got a B&M Street strip TH350 with a shift kit in it for $800 and free shipping off of Amazon. It was a pretty good deal since locally they wanted $1000 just for an over haul and reinforced sprags. Two years now and no problems yet. Bad part is they only warranty it for 90 days. Guess they are not too proud of it. The torque converter I bought would only be warrantied if the tranny was new, always a catch. So if you want a new torque converter as well now may be the time for that.

 

I called the guy who did my transmission and he said that it sounds like the TC is just not giving enough slip, ie. stall is too low. He recommended something in the 2500-3000 range. I asked about your scenario above and his opinion was that if the TC were completely locked, at 1k rpm idle, the car would lunge suddenly then die. As it is, where the car dies gently, he believes that the TC is slipping, but not enough for the cam and it is just bogging it down. I guess it is time to shop for a new TC.

 

Keep in mind that the guy who rebuilt the transmission has a vested interest in it NOT being a transmission problem. Get a second opinion from another transmission shop or two.

 

I took that into account, but I trust the guy. When I first installed the TC, I didn't seat it completely in the pump gear. When I put the car in gear the first time, I basically shattered the gear. I pulled the trans, took it back to him for a new gear. He disassembled the whole thing, cleaned everything out to make sure that there were no pieces of metal from the broken gear, re assembled the trans and installed a new pump gear, all at no charge. And this is on a rebuilt trans that he offered no warranty on. Anyone willing to do that much work, for free, when they are not obligated to do so earns a little trust in my book.

 

This transmission/TC thing has been a real pain in the butt for you so far. Hope it works out this time around.

 

Yes it has. I had a voice nagging me all night telling me to get a second opinion on the diagnosis offered by my trans builder. Called a few local transmission repair places and uniformly got the same response; "well, bring it in so we can take a look at it". Thanks, but no thanks. Called B&M and Hughes Performance and talked to their people. Both took a lot of time discussing my current set up and the nature of the problem. Both came to the same conclusion, not enough slip from the stock TC. Both suggested 2500-3000. I will order today and maybe get it installed this weekend, but a half marathon may wipe out my Saturday. Either way, I will update the thread with my results once I have completed the job.


Bryan

 

Sounds like they have no idea but willing to charge you to replace both trans and TC to fix it.

In mine I have the stall below my normal cruise RPM, logic being it will be more efficient and and produce less heat from slippage. Not %100 sure if that is really true though since it takes lots of torque to get it to slip near the stall speed. My brake stall is at 2500 and normal cruise at 65 mph is 2750 ish. Any of them recommend an additional cooler for the higher stall converter? In my research lots of folks recommended it. Some thought it was ok without it too.

 

I asked that question and the responses seemed to be that it depends. If you plan on driving it hard, it couldn't hurt and may be a good idea. However, if you are just talking about a weekend cruiser and just getting on it occasionally, probably not necessary.