TH 350 Torque Converter

[Domer]

This is a non lock up trans. I was able to go forward in all gears the rebuilder said the nut on inside of the trans fell off and everything was laying in the trans pan. I wish I never had this trans rebuilt by him! He has "30" years of experience too lol. I will try it in manual low today when I go to the shop. Ive just tried it going from park to reverse, park to drive and neutral to reverse and neutral to drive.

Same motor just have had a lot of motor work done to it. Im at 475 hp now.

Did you do this motor work while you were doing the swap? how high of a stall do you have on the converter? if you have a stock converter on that build, or a real tight low stall converter, then that would cause it to die when put into gear.

 

[foamypirate]

Did you do this motor work while you were doing the swap? how high of a stall do you have on the converter? if you have a stock converter on that build, or a real tight low stall converter, then that would cause it to die when put into gear.

That's kind of what I was leaning towards with my earlier question (asking if this engine was behind this trans originally). I'd say this might be the case, for sure.

 

[HotRodPC]

Did you do this motor work while you were doing the swap? how high of a stall do you have on the converter? if you have a stock converter on that build, or a real tight low stall converter, then that would cause it to die when put into gear.

That's kind of what I was leaning towards with my earlier question (asking if this engine was behind this trans originally). I'd say this might be the case, for sure.

Yeah, good point there. If it's a 475hp motor, I know it's no stock cam and isn't idling at 600 rpm. If you're needing to idle at 1200-1500 and have a stock stall, even though 1600-1800 is stock, that could be the issue.

So what happens if you just put it into gear without a foot on the brake and let it take off if it wants to?

 

[BigAl285]

I pulled the pan tonight. For just having the pan off by the quality rebuilder with new trans fluid there is a lot of junk in the pan. I removed the filter to get a better look. The "rooster tail" wasn't straight. I tested it before fixing it and it would go inbetween 1st an 2nd gear. I loosened up the bolt and realigned it so it was centered. Cleaned up the trans pan, filled and tested it out. It is better now it will sort of idle. Looks like need a larger stall converter. It is a Big End 2000 stall that I bought from a local speed shop. The speed shop runs them in some of their cars and have good luck with them. My truck will go into gear and not die right away now like it did. It will stumble and sorta run. Soon as I touch the gas it will move no stall at all. Now it looks like I need a larger stall torque converter, thought a 2000rpm stall would have been enough.

This motor was bolted to this trans and torque converter before the frame swap and motor work. Originally it was a 9 to 1 compression 383 with intake. now its 11.5 to 1, aluminum intake, port/polish, 2.02 fuelie heads that where redone, 750 holley carb that was jetted up a few sizes. Same cam is used 500 lift.

 

[HotRodPC]

That really sucks you pay someone to build **** to avoid all these headaches and have to go thru all that. And fluid isn't cheap these days either. I'd have reused the fluid but if it had that kind of junk in it, not sure I would have unless I could strain it real well. I kinda figured the Rooster tail would be part of the problem as it seemed to be hung up with pressure not going where it should have gone, and the bolt falling off kinda confirmed that.

I kinda screwed you here too. There is a way to KNOW 100% certain, that the manual valve is in it's correct spot. I just freakin forget now without looking at a trans apart. I can't remember now if it's, Park, N, or D, but with the trans in whichever gear, the manual valve is supposed to be flush and smooth with the end of the valve body hole. You know how the manual valve actually goes all the way thru the bore and sticks out the other side? Which ever gear it is, that valve will be flush with the end of the bore and that is how to tell for certain that the manual valve linkage, S clip and rooster tail are in proper shape and not bent. It would have been nice for you to know that before you pulled it apart and been able to compare or know how far off it was. All it takes is to be off 1/8in or so, and then you have fluid pressure bleeding into passages that it shouldn't and maybe lower pressure where you should have it. Sorry bout that. I did think of it, but moving, I think my book that covers that is packed and moved 70 miles east of here. If it comes to it where you end up taking the pan off again, DO NOT do it until we have the definate info on that, so you can make 100% certain it's correct.

 

[BigAl285]

That's fine, only way for me to learn is to do it. Pulling the pan isn't that bad. I will be running it and changing the filter so I will have it off again. If I wanted it done half correct I could have done that without having the tools. I would have atleast had everything clean. Do you guys think I need a larger torque converter then?

 

[HotRodPC]

You just might need a higher stall. But, I'd also have a conversation with your speed shop or the converter guy you got that 2000 stall from and see what his opinion is. I really doubt your idling at 2000 rpm, and as heavy as these trucks, you should be able get a true 2000 rpm out of it.
Usually ratings are just that, a rating. You tell a guy I want a 3000 stall converter, and he'll go get one off the shelf not knowing it's a C60 dump trunk that weighs 5 tons, or a Monza that weighs 1600 lbs. A good guy like Edge Converters in No Cali, builds race converters customs. You tell him what you want, and he asks, about the motor, the weight of the car, the gear ratio etc, and he builds what you want and will be within 100rpm either way every time. So weight can make your stall higher, but then lower gear ratio can compensate for that too. So many things are considered.

So now that the truck at least sorta idles, when you put it in D, and foot on the brake.. Does it feel like it's trying to lunge or learch forward? If it does, then for sure you're not getting the stall out of the converter, if you're idling at 1500 and supposed to be a 2000 but it got a lunging forward feel to it.

I don't have a tach hooked to my 85K1500, but when I built my budget Th350 for it, and didn't have cash for a converter, I used the cleanest looking converter I had from a known to be good trans that I had in stock. It was out of a 79 Monza behind a Buick 231 V6. I'd have to say I'm probably getting 2200 stall out of it in my 85 K1500 on 31x10.50 tires and 3.73 gears. I actually like it. I had intended on swapping it out later on, but I like it enough, I'm leaving it in there. Of course, being a Monza converter, I doubt it's built very stout so I can expect to wear it out or break it in short order.

 

[BigAl285]

Ive been running low on money especially now haha. When I got this one I told them what it was going in, motor, trans and tire size. I will never go back to where I got my torque converter and my motor work done at. They did everything fine on my motor but didn't call to give me a update on the price and did more then what I wanted done.

When its in drive I hardly tap the gas and it goes or if I let my foot off it rolls. I don't have a tach yet. That is on my list to get but not right away.

 

[BigAl285]

I got a B&M torque converter with a stall of 2500 rpm. I gave them my cam info and what it was going in and that's what they said to use. I couldn't afford a Edge Converter or other brands I just looked at there prices on the internet. I went with what I have heard of. Put it in and that thing rips. I might have to jet it back a size on primary it loads it self up. Thanks for the help fellas!

 

[HotRodPC]

I got a B&M torque converter with a stall of 2500 rpm. I gave them my cam info and what it was going in and that's what they said to use. I couldn't afford a Edge Converter or other brands I just looked at there prices on the internet. I went with what I have heard of. Put it in and that thing rips. I might have to jet it back a size on primary it loads it self up. Thanks for the help fellas!

Good News !!! Glad to hear it. So you got quite the lesson on this project.

Many times, coming here does end up being much more helpful than taking yoru vehicle the repair shop. Some people at those shops are just idiots, like your trans builder for example. He should have been able to tell you which converter you needed or at least had the conversation. When I do a trans build, first thing I ask is what type of vehicle and what's it's use. As in, is it a stocker? Daily Driver? Light to Mild off-road use? Extreme off-road use? HiPo? Street/Strip or what. All of that matters bigtime. But I guess if you're dumb enough to not even know to check the manual valve linkage and know to tighen your bolt to the linkage you wouldn't know to ask how the trans needs built or what converter might be needed.

Then of course, the other reason it works to come here, maybe not because someone is stupid, but because fact is, more heads are better than one when it comes to diagnostics. Just a bit harder to do diagnostics over a text description of the issue and not being hands on with it.

But Hey, it's all good now. Enjoy !!!

 

[crazy4offroad]

Glad to hear you got it fixed, I'm looking at higher stall converter too.

 

[BigAl285]

I remember when I had the trans rebuilt by him I told him what it was going in and what I was going to be doing ( street , truck pulls and the motor will be built up) I had a idea going in what I wanted and what everything should be doing he had no clue. Oh well live and learn.

 

[HotRodPC]

Glad to hear you got it fixed, I'm looking at higher stall converter too.

It was kinda cool. While going thru the shed out in the yard to get some stuff moved I found my old 3000 stall converter for Th350/400. Fluid still in it, looking as pretty as can be. I had a conveter cap over it. So it's stayed dry for these 10 years or so it's been in the shed. I hope someday to need a 3000 stall again. I was getting 3100-3200 stall out of it in my 64 GMC 3/4 ton with Dana 60 Limited Slip 4.56's and 31x10.50 BFG All Terrains. I had it built by a local converter guy who builds all the race converters for most of the guys who go to the track. It only got taken out cuz I snapped the input shaft and when I rebuilt the trans, I put a stocker back in it, knowing I was selling the truck and didn't want to let the converter go on the intermediate dogbone sprag and drum. I still haven't found that drum though, and I'm a bit pissed. I have a feeling someone stole it, and I know who, but they are long gone now, and it would have been stolen many years ago.

I remember when I had the trans rebuilt by him I told him what it was going in and what I was going to be doing ( street , truck pulls and the motor will be built up) I had a idea going in what I wanted and what everything should be doing he had no clue. Oh well live and learn.

It's a tough lesson and hard one to blame yourself for. When you pay a guy you expect he knows what he's doing. Now you know, keep your ears open for someone who is real happy with a hipo trans build or if you see someone abusing the hell out of their trans and it's holding up well, hit them up and ask who they have build their transmissions, cost, and past problems etc.

 

[BigAl285]

Well here is an update for you fellas. New stall installed. Took trans for a test beat and still can't feel the shifts. I cranked up the modulator valve checked vacuum lines all good. Took it around the block. Shifted ok. Well thought its from the stall torque converter. So I planner on getting the valve body reworked. I took it from the place where I used to work on it at to my garage. I bought a house pretty pumped. I drove my truck home and the trans wasn't acting right. I let it sit for a few weeks l pulled it an set it to a trans shop that specializes in th350 trans. Got a call today...... Case is junk, internally messed up. About only thing good is the modulator valve and some of the clutch pack discs. The guy sanded the valve body surface on the trans so its not straight. I lost track of everything. They haven't seen one this bad before. Lesson learn, take it somewhere or have one you you guys do it for me.

 

[foamypirate]

Well here is an update for you fellas. New stall installed. Took trans for a test beat and still can't feel the shifts. I cranked up the modulator valve checked vacuum lines all good. Took it around the block. Shifted ok. Well thought its from the stall torque converter. So I planner on getting the valve body reworked. I took it from the place where I used to work on it at to my garage. I bought a house pretty pumped. I drove my truck home and the trans wasn't acting right. I let it sit for a few weeks l pulled it an set it to a trans shop that specializes in th350 trans. Got a call today...... Case is junk, internally messed up. About only thing good is the modulator valve and some of the clutch pack discs. The guy sanded the valve body surface on the trans so its not straight. I lost track of everything. They haven't seen one this bad before. Lesson learn, take it somewhere or have one you you guys do it for me.

Damn, that sucks. I'm not too surprised about the case being junk. My trans builder said he usually goes through 3-4 TH350 cores anymore building a single trans because they are just so worn out.