Question: Tq converter Lock Up issues

slowlmm

New member
Mar 2, 2008
2,582
0
0
45
so cal
I belive my tq converter may be toast. with just over 20,000 miles under wot truck revs to 3500 rpms before it locks. and some times wont lock untill I let off the gas a little. and it will also lock and unlock also by itself. It seems its been getting progresively worse. I have changed tunes both ecm and trans put stock tunes in ect ect still the same issue. IS there a possibilty it could be something else besides the converter ? or is my converter going out? i have been haveing theese issues before with my old motor as well. its just getting worse and worse. I have a 1058 Any ideas Thanks.
 

Mike L.

Got Sheep?
Staff member
Vendor/Sponsor
Aug 12, 2006
15,681
232
63
Fullerton CA
You need to watch it with a Tech 2 and see when the command comes in. When the command is given you can watch it pulse on in about 3 stages, 37-67- 97%. 96 or 97 is full lock, you never see 100%. Once locked, you will see 0 rpm slip or anywhere from -5 to plus 5 or there abouts.
 

Cougar281

Well-known member
Sep 11, 2006
1,805
249
63
St Louis, MO
I think there's also a table *somewhere* in the TCM's that'll only allow the converter to lock when there's less than a certain amout of RPM difference between the engine RPM's and input speed. If the converter's too loose, it's possbile for it to be outside this range, causing it to not even command lockup until it is within range, such as when you let off the go-pedal.
 

slowlmm

New member
Mar 2, 2008
2,582
0
0
45
so cal
I think there's also a table *somewhere* in the TCM's that'll only allow the converter to lock when there's less than a certain amout of RPM difference between the engine RPM's and input speed. If the converter's too loose, it's possbile for it to be outside this range, causing it to not even command lockup until it is within range, such as when you let off the go-pedal.

Interesting would the converter get looser over time or if it was defective ? can the converter still be bad. but once it achives lock up not slip? what defines a bad converter?

When the coverter was installed it didint do any of this and then progresivley has gotten worse as time went on. mike Its not a slip issue but a non locking isssue as when its locked it +or-10 bounces around in there. I know others that have had simular issues with the 58. I have had issues with the converter unlocking on the freeway ect and have had people in the truck when its happend as well. it shouldent be a tuening issue as the truck has run the same tunes in when it didnt have the issue. I can basicly only drive the truck in th mode now becuase thats the only way to get it to lock under wot.?
 

duratothemax

<--- slippery roads
Aug 28, 2006
7,139
10
0
Wyoming
I think there's also a table *somewhere* in the TCM's that'll only allow the converter to lock when there's less than a certain amout of RPM difference between the engine RPM's and input speed. If the converter's too loose, it's possbile for it to be outside this range, causing it to not even command lockup until it is within range, such as when you let off the go-pedal.

yup yup yup!!

ding ding ding! Ive been saying this for 2 years and begging EFILive to find the table. If we find this table the allison will improve 10x as far as being a CONSISTANT race transmission, and the need for a co-pilot or other expen$ive lockup controller will dissapear.

Tommy- a bad converter WILL aggrivate this issue. My 1057 had over 80,000 miles on it, and over the past year it had been loosening up severely. It was so bad that id drive it in tow/haul all the time. If you went WOT from a stop, it woudlnt lock until like 65mph because it was so loose and the TCM would freak out. I had my converter refreshed and it feels 10x better. BUT I have yet to go WOT from a stop and see if it locks up *now* because im too afraid to go WOT. You know, im just gun shy from blowing up 2 motors. :eek::

ben
 
Last edited:

Mike L.

Got Sheep?
Staff member
Vendor/Sponsor
Aug 12, 2006
15,681
232
63
Fullerton CA
Interesting would the converter get looser over time or if it was defective ? can the converter still be bad. but once it achives lock up not slip? what defines a bad converter?

When the coverter was installed it didint do any of this and then progresivley has gotten worse as time went on. mike Its not a slip issue but a non locking isssue as when its locked it +or-10 bounces around in there. I know others that have had simular issues with the 58. I have had issues with the converter unlocking on the freeway ect and have had people in the truck when its happend as well. it shouldent be a tuening issue as the truck has run the same tunes in when it didnt have the issue. I can basicly only drive the truck in th mode now becuase thats the only way to get it to lock under wot.?

If the converter was defective, T/H would make no diffence because it is only a different strategy. Still sounds like a command issue.
 

duratothemax

<--- slippery roads
Aug 28, 2006
7,139
10
0
Wyoming
mike the converter can be shot but the lockup clutch still good (and able to hold power) no? This is exactly what happend to mine. :(
 

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
13,686
736
113
Texas!!!
I think mine has been doing the same thing. If I go WOT without turning my copilot to race mode, my converter won't lock until I get up to around 70 mph, T/H or regular. Even when driving in normal mode with somewhat spirited driving (but not WOT) it will sometimes wait until close to 60 or a little higher before it locks. Doesn't do it in T/H unless I go WOT.
 

slowlmm

New member
Mar 2, 2008
2,582
0
0
45
so cal
mike the converter can be shot but the lockup clutch still good (and able to hold power) no? This is exactly what happend to mine. :(

sounds like whats going on with mine. holds power once locked but. othere wise is pretty much pooo. Im willing to bet if the converter get changed the problem will be solved
 

Mike L.

Got Sheep?
Staff member
Vendor/Sponsor
Aug 12, 2006
15,681
232
63
Fullerton CA
sounds like whats going on with mine. holds power once locked but. othere wise is pretty much pooo. Im willing to bet if the converter get changed the problem will be solved

I told you I would change it. Sell your engine yet?