highway speed surging

[qtacclia]

When driving down the highway the rpms will go up 300-400 rpm and drop back down. I am on flat ground no grade. It even does this on decline with cruise on. I have had it do this with cruise off and o/d off. Does it moreso with overdrive on that not. Checked fluid not burnt but looks over full. I don't know of an accurate way to check fluid. Everytime I check it on anything I've had it's always been way up the stick. Any help appreciated any questions I'll try to answer. I did have new tires put on about 6 months ago and the speedo has been reading 5 mph fast. They are the same size as stated on the door.

 

[qtacclia]

anyone????

 

[N1265]

how many miles ?

 

[qtacclia]

185,000

 

[jlsparky7]

You should check the trans fluid level with the engine running so the torque converter can fill up with tranny fluid.

Have you gotten the codes pulled on the vehicle? Is it a shifting problem or a engine problem? Hard to tell from your description.

 

[qtacclia]

There are no codes. I have tried to check the fluid level with the truck running but the fluid is way up the stick. Its not like check oil level where it doesn't stay in the grid area. Every vehicle I've had new to old the trans level was hard to check. I' tried to check running in park and running in neutral. The truck is not under a load when this happens. I am on the interstate usually with the cruise on and the rpm's will go up 3-400 speed doesn't increase. I have just recently got a noise from under the truck that is hard to explain but it sounds like a zip tie hitting the bottom of the truck. Someone at worked asked me if the torque converter was going out and I said I didn't think so because it was shifting fine. You can't hear th enoise will driving only when you stop and the truck is idling usually in park.

 

[my98nnj]

The torque converter locks up in 4th and 5th gear when your crusing at a steady speed. It will unlock if you take your foot off the gas to coast. Stepping on the gas again causes an increase in RPM's just before the converter locks again. Even the cruise will cause this to happen.

Is that what your seeing?

 

[qtacclia]

I understand what you are saying but it is doing it down hill, level ground everywhere that should stay at a steady speed. I don't lose speed before it does this and i don't gain any speed when it does this. It just started a couple weeks ago.

 

[jay_c]

This is exactly the problem I am having. I would like any kind of input, if anyone has some...anyone?