what happens when torque converters start to go bad or go out?

do they slip real bad off the line?
do they just quit and your truck won't move?

and is it very common for them to go out on our trucks?

 

I had one go bad, and if yours is bad youll probally need to rebuild the trany from contamination, however mine would work but as soon as any boost was applied there was severe shudder from the truck. torque converters usualy do not go bad, if you want a more in depth explanation ask gregg evans.

 

I dont think it's to common. However, I just had mine replaced yesterday. Here is what happened to me.

It started 2months ago. Ocassionally when I came to a stop the truck would die. It would act like you were not pushing in a clutch on a manual trans when coming to a stop.

The dealer had it for a week and found nothing wrong. No codes were thrown and of course it didn't mess up for them.

This past weekend it got much worse. While idling in drive
the torque converter locked and the engine bogged down and died. It did this twice in one day.

I got it to a shop and they put in a new converter. I just got a stock one put in again. Supposively it's a descent converter.

Was it slipping?? not sure. After driving with this new one I think it was but I'm not sure.

-Rich

 

Ah i forgot mine did throw an engine code,it was a code for the converter not loking up, so it sounds to me like yours was locking up when it shouldnt have been leading to the engine stalling, cus if it was slipping it wouldnt have caused the engine to bog and then stall.

 

A torque converter only slips when it attempts to lock, there is no real slip in a fluid coupleing (well, by definition a fluid coupleing is slip, but you get the gist) If the clutch is worn out, it will slip on lockup, but not off the line.

If it was built before 3-03 the most likely mechanical thing that can go wrong is the 812 thrust washer will get contamination for the tranny on it and eat the phenolic washer on the reactor, this is pretty bad and the converter is toast if it happened. Trannies built after 3-03 have the 812 thrust washer replaced with a torrington bearing and that pretty much solves that problem. It's much much more common for a tranny to trash a converter than the other way araound, aside from the aforementioned 812 washer and the coverplate splines from the triple disc converters (all Lightnings have stock 3 disc converters) there just isn't much in a converter to break. The impeller and turbine are furnace brazed so they hardly ever break, and the torrington bearing on the turbine hub and or the reactor will only break if they were installed wrong in assembly and that ussually doesn't take long to fail, UNLESS you balloon the converter, and then you will often lose the bearing on the turbine.

Hope this helps,

G

(home of the Jimmy Dog!)

 

 

So, can a torque converter cause this to happen?
Obviously I am hoping it was the converter.

BTW. Greg, I just sent you an e-mail with a bit more details.
Thanks for helping me through a lot of this mess.

and what does this mean: "UNLESS you balloon the converter"
Thanks,
-Rich

 

Under very extreme conditions, the converter cover can actually expand a little and sometimes it's enough for the bearing on the hub of the turbine to fall out of place, when the converter contracts again, it pinches the bearing out of location and this will cause a lot of damage and ferrous contamination. This is extremely rare in gas units (not real common in diesels, but it does happen) and after 1998, the torrington bearing was changed to give it a bigger lip and this prevents it from happening very much at all.

A build date of 3-3-3 I think still had the 812 thrust washer, I'm not sure but I think the change was about the 23rd. Or at least that date sticks in my mind. I have posted the exact date before, if you want to do a search.

G

 

The most common faliure I find in 4r100 converters is damage to the lockup piston and front cover(multiplate only).
Here is a picture of the lockup piston showing how it wears.
Sorry glare got the best of it I will try again to get a better picture.



Here is a picture of the front cover showing how the plate wears into it.


Here is a picture of the same front cover giving a better view of how the cover itself looks.


Here is a picture of what the 2 parts look like together. It shows how the damage was done.


When this occurs the lockup piston will either be stuck on,be stuck off, Or make a terrible thump noise when applied.
This also leads to contamination of the converter and transmission.

 

Thanks for the pics Alan, I've tried to explain why we don't use the triple disc, but that shows it pretty good. (Disclosure, Alan builds all Factory Tech Converters now, except for the Monster Boxes, which Jasper builds the exact same way).
The extra clutch surface would intuitivley be a good thing, but the extra moving parts, contamination etc... that goes along with it I don't think is worth the problems they can create down the road.

G