Car help - My truck "jumps"

[Halliday]

The specs: 89 Chevy Suburban, 104k miles, K2500 model I belive. 2WD, automatic transmission.

I know it is a truck and not a sportscar, but sometimes when I try to gun the engine it will "jump." What I mean by that it it seems to stick for a second and then continue moving. I notice it most when I am driving "agressively" but sometimes it just does it on it's own.

What should I be looking for as the problem? Tranny? Gears? Gearbox?

Thank you for any help

[Mister Sinister]

So when your saying jump are you talking about it actually kicking down a gear? Or is it just the motor stumbling then catching up?

[Python14]

Sounds like a tranny problem.....and not a cheap one either.

[Halliday]

The problem the best I can describe,
imagine you are driving, going forward, and for 1 second you hit a brick wall. Then you are moving again.

I can't tell if the tranny is "jamming" or the engine is trying to catch up. That's why I added the bit about acceleration. It happens most often when I am trying to really speed up quickly. It has just happened when I'm cruising down the interstate too not really trting to accelerate.

I know it needs work done on the muffler and back brakes, but this seems like it could be a bigger problem.

[Mister Sinister]

Does it feel kinda like its going into neutral... Then engine revs up but its not going anywhere.. .then it catches.... and does it do it when it should be changing gears? either during normal acceleration or when you are driving romping the gas and the tranny should kick down... If this is the case it sounds maybe like the bands in the tranny... they could be bad or just need adjusting... but adjusting is usually just a band aid fix

[Halliday]

No it's not in neutral. There's no coasting involved. It more of a slam. A stop in mid drive. *Sigh* Guess I'll visit my tranny guy Mon.........

[Mister Sinister]

It doesnt feel like its locking up does it?

[Halliday]

It doesnt feel like its locking up does it?

That is a good way of putting it, but that also sounds bad $$-wise.

[Mister Sinister]

Hmmm... kinda hard for it to lock up then release without it breaking something... i wish it was a manual tranny i know those much better than i do automatics ... Hmmm.. .at this moment sorry i'm outa ideas... other than take it to someone to look at...

[Halliday]

That's cool. My tranny guy is super-nice and seems to know is stuff. It's just the thought of putting a lot of money into an old truck that scares me

[dj89]

what speed dose it do it a round what are the rpms around.

or dose it just happen when ever?

[Halliday]

Crusing highway speeds: 65mph
I've had it lockup in town too, that was the time I was speeding up. Then it was around 30-40mph.

It seems that I can make it lockup if I try to gun the engine. Would that be the gears jamming/not switching?

[dj89]

well i thought it may be your tranny lost a gear and is going from like 2nd to 4th but i can't tell your for sure unless i drive it

[Halliday]

95% of the time it is fine. It seems to act up once in a while on it's onw, and if I try to speed. So now I am a very nice driver

[ryanshep]

that happened to my dads jetta.....cost him a new transmission....