My 1999(gm400) Yukon SLT is not moving.

[Blackandgold51]

Okay, let me start of by saying this. After I had installed a new starter for my Yukon I've found out a problem that I did not have before I had installed a new starter to get the truck running, after it was sitting for a while for like a couple to a few months without moving. The truck had a problem backing out of the driveway which the there's a little hill-like bump that tried to climb while in reverse, so in order for me to get out of the drive I had to move the truck up for about 2-3 yards and then put the truck in reverse and let it go on it's on for 2-3 seconds, then I hit the gas hard to get the truck out of their over that bump coming out the driveway.

Now it did have a problem driving forward but for some reason it had a problem getting out of that driveway which it did not have before it was sitting for a while before a new started was installed.

Also, since I go to automotive school I've told my instructor about the problem and he said that it's 2 things since my truck have been sitting for a while before it was started; It's either that the truck needs it's Transmission fluid changed along with a new Transmission Filter or it needs a new Transmission. So I'm thinking that since the truck have been sitting for a while with the Motor Oil that haven't been changed and things like that, that it might needs a new transmission fluid and filter.

So, can you tell me to further back up this evidence?

 

[MOBS]

Unless it needed new fluid/filter before it sat up for the 2-3months, then I doubt it needs it now. Alot of my vehicles have sat longer than that and a couple haven't been moved in ages, but I can 99% guarantee that if i went out and threw a battery in them, they'd move with no problems. It kinda sounds like it's either not getting any fluid movement(or not much) through tranny or the torque converter may be dry?

 

[Blackandgold51]

Unless it needed new fluid/filter before it sat up for the 2-3months, then I doubt it needs it now. Alot of my vehicles have sat longer than that and a couple haven't been moved in ages, but I can 99% guarantee that if i went out and threw a battery in them, they'd move with no problems. It kinda sounds like it's either not getting any fluid movement(or not much) through tranny or the torque converter may be dry?

So I might have to change the torque convertor.

 

[MOBS]

I've had an old 78 model that did what you're saying, now I know they're different, but you almost had to redline the engine to move and it was just a creep even then. Took it to a tranny shop and they said it was a bad torque converter, they didn't say why it was bad or what part in it was bad, just that it was bad. They replaced and it lit up like a bat outta hell outta there. So yeah, it's possibly your torque converter.