2003 TB transmission slips in 3rd

My daughter just gave me her 2003 TB; about 180,000 miles. She never serviced the tranny but changed the motor oil religiously. She went to take it out one day and it wouldn't shift out of 1st. There was no warning, such as, sluggish shifting, hard shifting, slipping.

I dropped the pan, (no metal shavings just some grey slimy gunk) changed the 2 shift solenoids, filter and fluid. Now the TB has first and second but acts like it goes to neutral in third (no third). Before I give up on this tranny I was wondering if there is anything else I should look at: vacuum leak, known electrical issues with the tranny, PCM? It does not set any codes.

Thanks for any help/suggestions you can give.

Your problem is internal, a trans shop would a scanner that can command 3rd, see what happens

alright, I'll give that a go. just looking for a good winter beater with 4wd. this one was free.

thanks for your response.

alright, I'll give that a go. just looking for a good winter beater with 4wd. this one was free.

thanks for your response.

being a 2003 and never serviced the transmission has dexron III in it . this fluid is no longer an approved fluid . dexron VI is now the proper fluid. GM changed this because this fluid turns to acid after about 20-40K miles. depends on how hot the fluid gets . more heat the faster the acid.

so what happens is the valve bodies get eroded. then the loss of pressure.

a transmission shop with the knowledge can externally determine whats worn.

solenoids are just the electrical. valve bodies are what I believe is worn though you could also have a cracked shell as this is weakened by the acidic fluid.

2006 GM was loosing a lot of money on warranty repairs because of dexron III.

I use mobil synthetic transmission fluid since 1999. still have these 19/14 year old vehicles with no problems and little pan debris.