convertor stall problem
 

Maybe,the last couple of times at the track i have been having this problem with my stall speed changing, i would trans break stall it in the pits and it would zing right up to 6600 but when i would stage and come up on the break it would only go up to 3500 and that would make for a very lazy run.Has anyone else had this problem and am i thinking right that this is a convertor problem.

Re: convertor stall problem
 

It could very well be a sprag problem . If the sprag is not holding the stator in a fixed position, you'll have no torque multiplication and a very low stall speed.
What size , make, etc? Is it designed for trans brake usage?

Re: convertor stall problem
 

8 inch built by mike munsinger and built to be used with trans brake.

Re: convertor stall problem
 

Maybe you could talk to Mike about converting it to a mechanical diode type of sprag. That is, if he's available and not too busy,

Re: convertor stall problem
 

It sounds like a sprag problem, just as Mark said ... I had one go and the car wouldn't leave the line and started to pop ..
It wouldn't stall above 2,500 on the starting line and felt real flat, lost ET & MPH big time.... Get someone to look at it ASAP.....

Re: convertor stall problem
 

Good i thought that may be the problem, i am in the middle of changing out the transmission and did'nt want to put it back in and have the same problem pop up and by the way i am only changing to another powerglide with higher ratio.Thanks guy's

Re: convertor stall problem
 

More likely, the stator shaft in the pump is slipping. A sprag usually is either good, or bad, it either holds, or it doesn't. If it works, then doesn't work, then works again, it is most often a slipping stator shaft in the pump. Have the converter repaired because the stator shaft slipping can damage the converter. But it sounds a lot like the stator shaft is slipping.

Re: convertor stall problem
 

So, do you know why a stator shaft would fail,and what would be the likely cause of a sprag to fail.The reason i ask is i need to know if it is something that i am doing are is just routine maintenance.

Re: convertor stall problem
 

Well i took the convertor to the shop and the convertor guy said there was nothing wrong inside the convertor ,so it looks as though i am still left with the same problem.One thing that i am going to do is change transmission,also the trans guy ask me to check the big input shaft to see if it turned and it did not so what was he checking for.

Re: convertor stall problem
 

It's not an input shaft, it's the stator shaft. Did you try to turn it with something similar to Channel Locks? If the problem is intermittent, the stator is probably not hand turning loose. Swap pumps. Did he take the converter apart?

Re: convertor stall problem
 

A sprag or roller clutch inside the converter is difficult to check for damage without disassembly. The inner and outer races will show skid marks, that may hold fine using hand power, but will slip or skid under engine torque. What type of transmission do you have. Some stator shafts are a seperate part that is press fit into the pump cover, but others like a 200 THM are a one piece part .

Re: convertor stall problem
 

No Allen i just tried to turn it by hand,and yes he said the convertor was apart and there was no problems with it.The trans is a 1:82 pro tree powerglide.

Re: convertor stall problem
 

A good converter builder will usually spot a bad sprag with the converter apart. Normally, if there is a sprag problem even suspected, they just replace the sprag since the converter is apart, because a sprag isn't as expensive as the labor to put it in.

It should not be a problem to just swap the pump out in a PowerGlide, you don't even have to pull the pan, you just have to check the end clearance. I've swapped them in the pits, with the transmission hanging from a vise by a big Phillips screw driver.

It is almost a certainty that either the sprag is bad or the stator shaft is slipping. However, ordinarily if the stator shaft slips very much, it will usually spin by hand.