Car bucking around 45mph?

[tom5170]

02 gp gt, 204k miles, no idea if it's original trans or not. I changed fluid and filter 6,500 miles ago and added the transgo shift kit.

Yesterday I made a 80 mile round trip on the freeway. Today while driving across town 7 miles to work, I noticed my car kinda jerking back and forth once I hit 45mph while lightly accelerating. I tried accelerating harder and it didn't jerk at 45mph and shifted just fine with lots of power. So then I lightly accelerated again just to see and once it hit 45mph the rpms dropped and acceleration became slow.

The transmission shifts just fine on take off. Lots of power. It just has this issue at 40-45mph when lightly accelerating. If I accelerate harsher at that speed it doesn't happen.

Should I try disconnecting my battery and letting it sit a few hours? The plugs, wires, maf sensor, map, fuel filter, is all new

[Fivefingerdeathpunch]

If the shudder starts and you take your foot off the gas and get back on lighty again and it takes a few seconds for it to return, then my guess is that it's a torque converter shudder.

Taking your foot off the gas will unlock the converter for a tiny bit and will re-lock again once you lightly apply the throttle again.

[tom5170]

It just started happening this morning. Like I said when I was llightly accelerating it hit 40-45mphish it started bucking. I let off the gas and slowed down to about 30 and then accelerated lightly and once it got to 40-45 the rpms dropped - once or twice more i did this I was almost able to feel a very slight buck. If I accelerate harder this never happens and it shifts and gets up to higher speeds just fine.

I did notice since I had the car that sometimes lightly accelerating at higher speeds the rpms would drop off and it would accelerate up to speed much slower and if I let off the gas a bit and waited and then accelerated harder it would speed up just fine. But today was the first time it was more pronounced and it started bucking.


What would cause tc shudder?

[Scottydoggs]

o/d kicks in at 45 mph, good chance thats your 4 th hub taking a slow death and starting to slip.

[tom5170]

So on these cars 4th gear is o/d? So if I accelerate quickly up to 60mph that's 3rd gear and then it drops into 4th o/d?

I read all kinds of crazy ish from different websites about these transmissions and gears lol.

[Scottydoggs]

exactly. if your light on the gas it will go into o/d aka 4 th at 45 mph.

[tom5170]

I'm going to leave work here soon and drive it home and I'll try to watch and see exactly what it's doing again.

Is it bad driving it like this? I do mostly city driving where speeds might get up to 50mph max.

[Scottydoggs]

once it strips out all the way you loose 4 th all together. then its in 3 rd and runs about 2200 rpm at 65 mph. you know its gone when you shift between 3 and od and theres no change in rpm's at hwy speed.

[tom5170]

Ok so I drove home reaching 65mph a few times. I didn't baby throttle though and it drove just fine. When I was at 50 mph rpms Dropped in place at 1200-1300. When I pressed gas it would accelerate just fine up to speed. I'll try to accelerate slowly next time and see what happens. But like I said I wasn't really babying it but wasn't aggressive either.

Maybe it was how I had my foot placed on gas pedal and didn't realize it? I know when I place just the tip of my shoe on the end of pedal, it seems to be very touchy and will make the car hop and I've done this before and freaked out. I could've swore this morning was a tranny problem though.

[tom5170]

I drove 60 miles and it's shifting just fine. I hit 4th gear and rpms drop normally.

[Fivefingerdeathpunch]

If you drive mainly 50mph or under just stick it in 3. I did that everyday for 4-5 years as my commute at the time was 5-6 miles a day total. Never entering 4th gear is the best way to save the hub.

[tom5170]

Alright sweet will do, I drive 14 miles across town round trip 45 max.

[mnKISSgirl]

If you drive mainly 50mph or under just stick it in 3. I did that everyday for 4-5 years as my commute at the time was 5-6 miles a day total. Never entering 4th gear is the best way to save the hub.

My 2004 does this too - so just wondering - is it ok to leave it in 3 the whole commute (obviously if it's under 50mph)? Like, is it ok to start from a stop with the selector in 3?

[Fivefingerdeathpunch]

Yes, that's fine.

[mnKISSgirl]

cool, thanks