does this seem right?

[77 cruiser]

I`ve got a 99 Grand Am with a 2.4 with I think a 4T40E / 4T45E transmission. It shifts just fine except that the conv. locks in 3rd & then goes on to shift to OD. Is that the way they are?

Jim

 

[chris718]

that certainly sounds like a typical shift strategy designed into the vehicles ecm.

 

[77 cruiser]

Thanks, but is still seems odd & the conv. really slides into full lockup slow.

Jim

 

[6PacktoGo]

Originally posted by 77 cruiser
Thanks, but is still seems odd & the conv. really slides into full lockup slow.

Jim

Be advised that many late model GM transmissions use PWM (pulse width modulated) converter clutch lock up. The intended purpose is to soften up the engagement.

 

[77 cruiser]

Thanks it`s defintely soft.

Jim

 

[6PacktoGo]

Originally posted by 77 cruiser
Thanks it`s defintely soft.

Jim

If it is actually TOO soft, it SHOULD set one of several codes, for overtemp, slippage, or one or two others. If it IS really slipping, it won't be long until it turns blue from the heat.

 

[AxL87GN]

I am not quite sure on the 4t40/45e but I believe they run the ec3 converter apply strategy. It applies in stages and is real soft they seem to be making them all that way. They have had many problems with the pwm but most don't experience it till high mileage. If it bothers you that bad take it to a shop you trust and have them monitor the slip on their scanner. it should be 10 - negative fully locked , it won't set a code till the slip is over 250rpm.

 

[77 cruiser]

I`m going to have a friend that works at a GM dealer scan it for me. Thanks!!!

Jim