Torque Converter

[Supreme Cutlass]

How do you tell if a torque converter is bad? Mine looks kinda rusted, there's also a whine (edit; a bit of a rattle, too) driving, and occasional stalling in reverse.

[CutlassSL91]

wow someone with the same problems! My '91 4t60 has stalled in reverse quite a few times. there is also a nice clunk when setting the cruise and when stepping on the gas after coasting. along with overall clunkiness sometimes. other times it is good. It also whines around 3k rpms, sometimes. Also, it has a major lack of torque on most occasions, and other times, i will get to 30 without ever revving it up to 3k rpms. Have you had and Are these also similar side effects?

[corning_d3]

The only test to check the converter is a stall test. BUT, this test is hard on stuff, so...you been warned.. Start the engine and let it warm up to operating temp. Place the vehicle in drive and FIRMLY hold the brake and push the accelerator pedal to the floor and observe your engine RPM. This RPM number is your stall speed. Anything over 2800RPM's is a sign of converter failure. Remember, only stall test a vehicle for 3-5 seconds, then put it in park and let the transmission fluid cool a few minutes before shutting off the engine.

 

A rusted converter is normal. Most all of them rust after a while.

 

 

CutlassSL91,

 

Have you inspected your inboard CV Joints? I mean pulled it apart and inspected the bearings/cup? Your driveline slack seems to indicate a worn joint. As for the whining noise, I'd say thats the transmission fluid pump, or the power steering pump..

[Intlcutlass]

I NEVER knew that!

[z284pwr]

The only test to check the converter is a stall test. BUT, this test is hard on stuff, so...you been warned.. Start the engine and let it warm up to operating temp. Place the vehicle in drive and FIRMLY hold the brake and push the accelerator pedal to the floor and observe your engine RPM. This RPM number is your stall speed. Anything over 2800RPM's is a sign of converter failure. Remember, only stall test a vehicle for 3-5 seconds, then put it in park and let the transmission fluid cool a few minutes before shutting off the engine.

 

A rusted converter is normal. Most all of them rust after a while.

 

 

CutlassSL91,

 

Have you inspected your inboard CV Joints? I mean pulled it apart and inspected the bearings/cup? Your driveline slack seems to indicate a worn joint. As for the whining noise, I'd say thats the transmission fluid pump, or the power steering pump..

 

So what happens when you have like a 3500 stall converter?......test means nothing? gotta watch out for those with high stall converters

[corning_d3]

Well, obviously, a stock converter isn't gonna stall at 3500, ulness it's f'ed up(too much impeller to stator or stator to turbine gap).. If you have a 3500 stall, it should be no more a 300-400 RPM over if you stall test it. This IS an accurate test for all converters......A rule of thumb is no more or less than 400 RPMs away from advertised stall speed..

[z284pwr]

Well, obviously, a stock converter isn't gonna stall at 3500, ulness it's f'ed up(too much impeller to stator or stator to turbine gap).. If you have a 3500 stall, it should be no more a 300-400 RPM over if you stall test it. This IS an accurate test for all converters......A rule of thumb is no more or less than 400 RPMs away from advertised stall speed..

 

Yeah I know, just giving you a hard time, the only problem is if the people actually know what it "should" stall at, that or know how to actually use 2 feet while driving

[corning_d3]

Yeah, if you don't know the stall speed OR someone has installed a higher stall........ I'm a 2 footed driver..been driving manuals too long.

[z284pwr]

Yeah, if you don't know the stall speed OR someone has installed a higher stall........ I'm a 2 footed driver..been driving manuals too long.

 

Me too....but because I have been around racing all my life, imagine that....My lady friend always thinks I'm weird because I drive with 2 feet

[corning_d3]

lol..Apparently, driving with both feet can be difficult for some people. I had my cousin try it in his car 'n' we was goin thru the windshield...back glass.. I remember going from a stick to an auto. My clutch foot was used to a stiff manual clutch. You could imagine what happened when i left-footed the brake!

[dbtk2]

Well, obviously, a stock converter isn't gonna stall at 3500, ulness it's f'ed up(too much impeller to stator or stator to turbine gap).. If you have a 3500 stall, it should be no more a 300-400 RPM over if you stall test it. This IS an accurate test for all converters......A rule of thumb is no more or less than 400 RPMs away from advertised stall speed..

 

I have a stock converter in my STE and there's nothing wrong with it and it'll brake torque to 3500. Now for most w's, your theory there is okay. But there are plenty of stock cars that stall higher than 2800. The power of the car also has a lot to do with how much over the "stall speed" it will slip. If your car has 700ft.lbs. and you have a 2500 stall it will probably stall at 3500 no problems. To figure out what stall convertor you need for a car you need to take torque into account as well.

 

I've always been a 2 footed driver and it wasn't from driving manuals, I just never thought it make sense to use both pedals with one foot??? Don't see why you would do that? So I drive with two feet. I usually don't have any problems going from a stick to an auto either, but occasionsaly the first time I step on the brake in an auto I will hit them a little hard...but usually not.

 

Shawn

[corning_d3]

If a 2500 stall converter will stall at 3500, then why even worry about stall speeds when buying a new converter.....do some research.

[dbtk2]

If a 2500 stall converter will stall at 3500, then why even worry about stall speeds when buying a new converter.....do some research.

 

A torque convertor will slip more if you put more power to it. Take a convetor that slips at 2000 in a car that makes 150ft.lbs and put it in a car that makes 500ft.lbs. I garuntee it will stall at more than the 2k it did in the 150ft.lb. car.

 

Shawn

[corning_d3]

Okily dokily..I'm an idiot :shock:

[z284pwr]

I guess I'm weird or something, because I never have any problems at all going from manual to automatic to manual and back, and I drive a TSX everday, so you can imagine how touchy the brakes are, then go to an old Beretta with crap brakes, then back to the TSX, I guess you just learn the feel and smoothness over time?

 

Now this stock convereter in your STE stalling at 3500? That is quite interesting to me indeed. Mine stalls at a mere 1800 or so hence why my bottom end sucks. Maybe that is why your launch is so good, these cars at 3500 are nasty

 

I'll bet your car would love the chip I have, no boost ramp maps, no rev limiter, 12 psi all the way to 7800, etc. etc.

[dbtk2]

I guess I'm weird or something, because I never have any problems at all going from manual to automatic to manual and back, and I drive a TSX everday, so you can imagine how touchy the brakes are, then go to an old Beretta with crap brakes, then back to the TSX, I guess you just learn the feel and smoothness over time?

 

Now this stock convereter in your STE stalling at 3500? That is quite interesting to me indeed. Mine stalls at a mere 1800 or so hence why my bottom end sucks. Maybe that is why your launch is so good, these cars at 3500 are nasty

 

I'll bet your car would love the chip I have, no boost ramp maps, no rev limiter, 12 psi all the way to 7800, etc. etc.

 

TGP's also had higher stall convertors than the N/A cars did as well, but they aren't supposed to be 3500 stall, I think like 2200 or so but I could be wrong. My dads TGP is just chipped (K&N, chip, 160tstat, no cat) and will stall at 3000rpm. My STE only did about 3000 or so when it was stock but with the chip, etc...., the stall has gone up to about 3500. I don't brake torque it very much at all because it has full boost at 1800, so if you just mash the gas off idle it just sits there and smokes the tires off. I haven't brake torqued it at all with this trans, I only did it on very rare occasions when people would call me out on 50+ft. burnouts, so i'd just show them. My dads GTP has a "3000" stall but he can stall that at almost 4k IIRC, don't remember for sure.

 

My car would never make power up to 7800, the turbo is waayyy too small. When I want I can have no boost ramp, but the car is really nasty then so most of the time I just use my modified stock boost controller. (keeps boost ramp but allows me to raise boost level over what chip commands) I have a "boostvalve" boost controller that I put on it from time to time, and thats nasty. The boost ramp makes the car much more driveable on the street or strip.

 

Okily dokily..I'm an idiot

 

Let me know after you have an ASE certification in auto trannies, then maybe I'll look into what you're saying, since it goes against everything I've learned about torque convertors at school and what I've seen personally by adding power to a car and seeing the stall speed raise...

 

Just think about how a torque convertor works and you should easily be able to understand why more torque would make the stall speed higher.

 

Shawn

[corning_d3]

Ok, i've already passed my ASE tests on transmissions and drivelines, and engine performance. I gotta wait a year for the others...I'm still in college.

 

I understand what your saying about higher torque numbers affect stall speeds. All I'm saying is if you order a converter, they ask for all your specs(supposed too). So when you buy a 2500 stall converter for your engine, you can expect your stall to be 300-400 rpm's away from the stall you selected. Of course it's going to stall higher if i put it behind a 502 Ram-Jet with spray or something(It'd prolly twist my little converter in half!)

 

Here's a ?. When i bought my 3000 stall converter, i never planned on boosting my torque numbers much. But i just came across a 3.1 with a new garrett t3/t4 hybrid, matched to the engine, out of an '89? TGP. I plan on modding this engine pretty good. What i want to know is, what is the peak of your torque curve with all your goodies? I need an idea.. I swear I'm not post-whoring..

[dbtk2]

I understand what your saying about higher torque numbers affect stall speeds. All I'm saying is if you order a converter, they ask for all your specs(supposed too). So when you buy a 2500 stall converter for your engine, you can expect your stall to be 300-400 rpm's away from the stall you selected. Of course it's going to stall higher if i put it behind a 502 Ram-Jet with spray or something(It'd prolly twist my little converter in half!)

 

Thats all I'm saying. If you order a torque convertor for an engine making the output of what yours is, then yes, the stall speed should be within a few rpms off. But obviously there can't just be a generic "3000 stall" convertor for any engine. Thats what I was saying, and from what I was reading it seemed like you were saying that a 3000 stall convertor would stall at 3000rpm on any engine.

 

Here's a ?. When i bought my 3000 stall converter, i never planned on boosting my torque numbers much. But i just came across a 3.1 with a new garrett t3/t4 hybrid, matched to the engine, out of an '89? TGP. I plan on modding this engine pretty good. What i want to know is, what is the peak of your torque curve with all your goodies? I need an idea.. I swear I'm not post-whoring..

 

I have no idea what the peak torque is of my engine, haven't dynoed it yet. That will come around April some time. If I had to guess though I would say somewhere around 400ft.lbs at the crank, but I could be wrong. It put down 272 to the tires stock (which is around 340 at the flywheel assuming 20% loss)

 

Shawn

[corning_d3]

Well, all that arguing for nothing!! I see how I mis-lead there. What RPM is your max torque at? BTW, That's one hot ass little 3100! Makes me wanna go buy the Stage 3 turbo kit from DPP...

[dbtk2]

Well, all that arguing for nothing!! I see how I mis-lead there. What RPM is your max torque at? BTW, That's one hot ass little 3100! Makes me wanna go buy the Stage 3 turbo kit from DPP...

 

Not sure cause I haven't dynoed it yet. Stock max torque was at about 3600 from what I can tell on the dyno sheet. I expect max torque to come a little sooner now, but not sure.

 

Shawn

[mfewtrail]

1898 rpm is the stall speed of our converters(Turbo Grand Prix's/Turbo STE's) for what it's worth.

 

Shawn is right about the torque output of an engine changing the speed of which the converter will actuall stall(specifically engines that produce a good amount of low end torque like our turbocharged 3.1's do). 3,000rpm+ launches are pretty fun, but I don't do that very often.

[z284pwr]

1898 rpm is the stall speed of our converters(Turbo Grand Prix's/Turbo STE's) for what it's worth.

 

Shawn is right about the torque output of an engine changing the speed of which the converter will actuall stall(specifically engines that produce a good amount of low end torque like our turbocharged 3.1's do). 3,000rpm+ launches are pretty fun, but I don't do that very often.

 

My car doesn't have a prayer in the world of taking off good with the 1800 stall converter. I wish I could get 3000+ launchs. I can barely get the thing to move as it is. It takes off like a a damn semi its so bad. Our 4cyl TSX makes it look dumb. Hell I think its faster 1/2 throttle off idle than WOT. :oops:

[Supreme Cutlass]

The only test to check the converter is a stall test. BUT, this test is hard on stuff, so...you been warned.. Start the engine and let it warm up to operating temp. Place the vehicle in drive and FIRMLY hold the brake and push the accelerator pedal to the floor and observe your engine RPM. This RPM number is your stall speed. Anything over 2800RPM's is a sign of converter failure. Remember, only stall test a vehicle for 3-5 seconds, then put it in park and let the transmission fluid cool a few minutes before shutting off the engine.

 

 

Did the test today, I did it once for like a second and it went to about 2500. Then I did it again for a tad longer and it edged up till it got to about 3,000 rpms, is it shot?

[corning_d3]

If i remember right, 1800-2000RPM was stock stall speed for your vehicle, but my stock T.Q. stalled at about 2500. If your torque converter feels like a marshmallow(spongy, soft) and there's no direct feeling, it may be time for a replacement. It can be drove this way, but torque multiplication and fuel mileage will be down. Also, if the torque converter decides to swarm, it will ruin your transmission.. Getting a new one is best, but you could pick one up at a salvage yard, although you never know if it was took off a car that had a bad transmission in it. If you do decide to go with a used one, make sure it has been capped with some fluid left in it. Inspect the fluid for contamination(clutch material, metal shavings, etc..), and smell the fluid to see if it's burnt.

[Supreme Cutlass]

What is swarming?