1999 Silverado

[matuva]

Good day all,

I have a 1999 Silverado with 5.3l to check.

Transmission only have 1st and D

Unfortunately, my scanner can't communicate with the ECM, so I can't read any potential DTC.
MIL is off.

Any opinion?

Thanks in advance !

 

[THEFERMANATOR]

Sounds like a broken sun shell. When the sun shell breaks you lose 2nd, 4th, and reverse. Most of the time you will not get a code except maybe a gear ratio error.

 

[DiHdChevyGy]

Do you have reverse?

 

[matuva]

Yes, reverse is still working.

What's the "sun shell"?

 

[DiHdChevyGy]

If you are sure you have 1st, then I am lost. I was told that if it stays in 2nd or 3rd with a free wheel coast when you let off your throttle, you may be in limp mode and you have to have a tech2 to diagnose it. That's where I am at right now. Limp mode with no codes. Good luck.

 

[THEFERMANATOR]

Yes, reverse is still working.

What's the "sun shell"?

If you have reverse it isn't a sunshell. The sun sheel is a part inside that connects the front planetarys to the rear planetarys around 3 clutch packs. Basically it is the part that allows the band and reverse clutch packs to connect up to the output shaft. If you have reverse and no 2nd or 4th then possibly you have a problem in the band apply area. Need to know exactly what its doing and check it for codes.

 

[matuva]

If you have reverse it isn't a sunshell. The sun sheel is a part inside that connects the front planetarys to the rear planetarys around 3 clutch packs. Basically it is the part that allows the band and reverse clutch packs to connect up to the output shaft. If you have reverse and no 2nd or 4th then possibly you have a problem in the band apply area. Need to know exactly what its doing and check it for codes.

that is one part of the problem : couldn't not connect to PCM. My scanner (AEnginuity scan tool) can't open communication port and don't access to DTC file