Over Drive Doesn't isn't coasting

Maintenance/Repairs
1

I have a 1999 F150 4x4, with about 109000 miles on it. I drive my truck in Overdrive and now when I take my foot of the gas it doesn’t seem to coast anymore. It feels as if I was in Drive. Is my Transmission going?

2

I don’t know about Ford so I guess I can’t help, but My Dodge V8 doesn’t coast in overdrive and never has. It isn’t supposed to.

3

If you notice a difference, there is one. OD may not be engaging. Do you have a tach that would help ?

4

I imagine the OP means, it doesn’t roll as freely as it used to. On many vehicles, the OD selector just allows the TCC to engage when a set of predetermined conditions are met. The direct coupling is less resistance to the drivetrain than reverse driving the viscous coupling. If the TCC is not engaging properly, it might not roll as readily when you let off the gas. As dagosa mentioned, a tach would be the simplest way to determine if the TCC is able to engage properly.

5

OD seems to be engaging, I do have a tach and I’ve watched it and the RPMs are lower when it is in OD vs. D. Also when I’m in D I can tell by how it sounds.

6

So when you pull off of the gas it is coming out of OD (the rpms would go up abut 2-400)? Depending on what you’re doing at the time that might be perfectly normal.

7

On my '96 Dodge van if you are in overdrive when you let off the gas, the thing remains in overdrive and the TCC remains locked up. Therefore it doesn’t COAST. I had a '99 S-10 that the TCC would release if you let off the gas. The torque converter would hold back some. It wouldn’t exactly COAST.

8

I had a '99 S-10 that the TCC would release if you let off the gas.

Well, something sounds fishy then because I believe the GM design only disengages the TCC if the brake pedal is depressed or the vehicle speed falls below 35 mph.

9

I not only had a '99 S-10 but I drove a company '01 S-10 204k and it was the same way. They both had tachs and I know that this is true.

10

Twinturbo;
“If the TCC is not engaging properly, it might not roll as readily when you let off the gas.” Don’t you mean “disengaging”? If the TCC did not engage the car should coast freely. Also what do you mean by “viscous coupling”, is that the torque converter?

11

“Well, something sounds fishy then because I believe the GM design only disengages the TCC if the brake pedal is depressed or the vehicle speed falls below 35 mph.”

The TCC releases when you hit the brakes, let up on the accelerator, or drop below around 35 mph.

My Dodge V8 does not release whrn you let off the gas.