Hard shifts after fluid and filters change. Codes P0717, P0721

[Missiletm]

I recently serviced my Alison with the full service filter and fluid change and after driving it about 100 miles it started to shift hard from first to second. did it just a couple times, then stopped. Then after a week or so it became more often and then second to third as well.

It dosen’t do it all the time, but if I get on it, it really will shift hard. Threw P0700, P0717, P0721 Codes today.

Planning on checking the plug and wires on the speed sensor on the transfer case. The t-case fluid was drained and refilled when i did the trans.

my truck is a 2007 LBZ classic, bone stock, no tuning or mods, 230k miles

 

[Mike L.]

717 is turbine sensor and 721 is out put sensor. Odd it would throw both those codes at once. I would be lookig at the wires leading to each sensor and make sure the wires are twisted. 12-16 twists for every 12 inches of wire.

 

[Missiletm]

Thanks for the reply.

Where is the turbine sensor located? What about the output sensor?

 

[Mike L.]

Top of the case, rear part on driver side.

 

[Missiletm]

The problem turned out to be the 20 pin connector seal was leaking. There really wasn’t much fluid in the socket but the backshell of the plug was full of it. $10 part from Merchant Automotive solved the problem. Shifts like new now.

I unplugged the wiring harness from the transmission 20 pin socket, VSS, TSS and ISS and removed the old tape and covering inspected for wear and then retaped and wrapped it with a new cable protector.

 

[Mike L.]

20 pin connector had nothing to do with it. Speed sensor harness is where you fixed it.

 

[Missiletm]

If you say so.... there was nothing wrong with the wires.

 

[Bdsankey]

If you say so.... there was nothing wrong with the wires.

You unplugged them and plugged them back in right? Could have been a bad seat into the connector at the sensors..............................

 

[Mike L.]

If you say so.... there was nothing wrong with the wires.

This ^^^^^^^ coming from a guy who screwed up an oil change.

 

[Missiletm]

I screwed up an oil change? How?

Previously I had unplugged and plugged them in a few times. Even swapped the iss and the tss as well as replacing the speed sensor and that didn’t work.

 

[Missiletm]

This ^^^^^^^ coming from a guy who screwed up an oil change.

How do you claim I screwed up the wiring harness doing an oil change? Please respond, I’d like to know from an expert so it doesn’t happen the next time I do it.

 

[Missiletm]

Nothing? What a jackass.

 

[Bdsankey]

Nothing? What a jackass.

Mike is one of the most knowledgeable in the industry in regards to Allison transmissions, hell he’s behind some of their biggest innovations on the performance side. Keep calling people a jackass and I bet you’ll find a quick exit to your stay on the forum.


Sent from my iPhone using Tapatalk

 

[Missiletm]

Maybe so, but he doesn’t have to act like one when someone may disagree with him. That’s not cool. I came to this forum for help and the “expert” tries to shame me? That’s cool? C’mon Man....

 

[Mike L.]

Nothing? What a jackass.

People that get butt hurt easy don't last long here.

 

[Chevy1925]

People that get butt hurt easy don't last long here.

The man is not wrong. better put your thick skin on OP