4L80e Problem

[Silverado6.5td]

I have a 1998 chev 1/2 ton. The other day I was driving my truck and I lost OD and it started to shift hard from 1 to 2 and 2 to 3. Then it threw a P1870 code(transmission component slipping). I cleared the code and a couple days later I tried driving it again. It did the same thing once it hit operating temperature of about 150 degrees.

Does anyone have any thoughts as to what is the problem? Is the transmission toast? Could it be a worn valve body?

 

[docdray]

could be VSS, dirty electrical connection, burned fluid, low fluid level. 1. Is fluid color and smell normal? 2. Is fluid level normal @ hot idle? 2. when was last fluid change? 3. are VSS on tranny and Xfer case clean connections?

easiest are these. check fluid, then check vss's.

 

[Silverado6.5td]

The fluid looks good, smells normal and is at correct level. It was changed a few thousand kilometers ago when I had a transmission temp sensor mounted in the pan.

I haven't checked the VSS connections on the tranny or transfer case yet, but will soon. I am assuming VSS are the electrical connections?

 

[Mike L.]

I would say your converter is slipping. Put a Tech 2 on it and watch TCC slip. If it's between 35 and 50 rpm slip it's unacceptable and will throw a 1870 code. When this code is throw, line pressure elevates ( hard shifts ) and you will lose 4th gear.

 

[docdray]

Vehicle Speed Sensor, unlikely they are cause but could be. if tranny slip is more than 200 rpm from input to output you'll throw a code.

 

[Silverado6.5td]

I had my truck to the tranny shop today and they said it didn't appear mt TC was locking up even before it gets warm and I lose OD.

They also said that if my shift sensor is the original it could possible be the problem, but it has probably been changed with over 300k on truck and it most likely needs to be rebuilt.

Is there anyway to tell if the shift sensor is original or if it has been changed?

Where is it in tranny and is it easy to change?

Another thing interesting was that it usually got to 150 degrees before I lost OD, but the last couple times, I lost OD before the tranny even registered a temp on the gauge.

 

[Acesneights1]

Mine is doing the same thing. I think the tranny is toast. No codes on mine.

 

[Acesneights1]

I scanned it and found code 72 VSS. Service engine light was not on. I replaced he VSS and so far truck is back to normal. Dodged a bullet.

 

[docdray]

sweet, glad to have you back brother.

 

[Acesneights1]

Who was I kidding. I could never abandon my 6.5s.

 

[docdray]

we know, just let go and hug it out:grouphug:, Its going to be ok.