Torque converter/lockup

On my 86 Grand Marquis, the torque converter locks up as soon at it shifts into 3rd gear, no matter what speed you're traveling. Installed a heavy duty shift kit at 105K, and changed the fluid at around 128K but it has always done this, even prior to the shift kit installation. Tranny has about 138K on it now.

I believe the lock up feature is supposed to engage at around 40mph; this seems reasonable considering the low rpms below about 35mph.

Also, when letting off the gas from cruise, there occasionally is a shuddering, as if there is something tight in the trans that is not allowing it to coast

Any input would be valuable and thanks in advance.

I guess you're saying the torque converter is reaching it's 'stall speed'. I believe that's when it shifts gears.

I believe the shift points are marked with small dashes on the odometer as: "-- --".
At 10, 15-20, 30-35.

I think there's supposed to be another shift point around 70mph. But it doesn't. I've had it serviced a while ago, and I'm not sure about why it doesn't.
Unless one of the 4-speeds is hidden in the 5-45 mph range.

I've experienced the forward/backward "shudder", and it seems to be happening more since I added the dual cherry bombs. It's almost like there's a vacuum problem somewhere.

There was a vacuum leak in the automatic emergency brake release switch, at the base of the steering column (on firewall), but I fixed that about 3 years ago.

Sometimes I also notice since the exhaust upgrade, that it takes longer for the tranny to downshift at about 30-35mph.....often lasting until about 25mph.

But something I've noticed that helps the Tranny shift, is to lift the foot off the accelerator just at the moment it feels like the converter is about to stall.

Does this sound the same?

Yes as a matter of fact, there is a hissing noise coming from underneath the dash. You say that is the emergency brake auto release...Do you know how that effects the lockup for the torque converter? The shift points, aka converter reaching stall speed, seems to be correct. It's just that in 3rd gear, it goes straight into lockup, even if, say, it shifts at 18-20mph. Then have to get it to downshift back to 2nd to accelerate, when it should/could stay in 3rd and NOT be locked up and let the engine stay in the powerband. There aren't any mods on my car, it's bone stock (and yes to all those performance guys out there I would like to, but it's just not in the budget right now and Virginia requires stock emission stuff). Anyway I'll go look for that leak in the emerg brake release.

But I'm thinking it might be the converter itself? This car did sit for over a year prior to the time I got hold of it.

As far as one of my fixit manuals said, that either
the emergency brake release is either by the handle just above the emergency brake pedal, or by shifting from Park-to-Drive....not both.

However, mine does. If you remove the cardboard kickpanel under the dash, you'll see a white-tannish crescent shaped thing screwed to the firewall, and around the base of the steering shaft.

The hissing is probably coming from there. The hissing can come from the vacuum release hoses, but they're usually in new condtion.

It's amazing at what a little vacuum leak can do for overall engine performance.

Other than that, maybe the tranny pan is loose.
I've noticed sometimes going around a corner, can cause the tranny to slip into neutral.

When you say "lockup" is that downshifting, or upshifting?

One of the great things about having cherry bombs, is that I can hear the car shift better, and I can listen into the exhaust pipes for cylinder/valve problems.

Hey thanx for the tip, will take out the kick panel next time I work on it. (aka, soon). If that's engine vacuum powering that, I can see where it would make a difference.

As far as the Em brake, mine will release either way also, by putting in drive (usually overdrive won't work....vacuum maybe) or by pulling the lever.

The lockup definitely engages in a 2-3 upshift, and seems to stay engaged in a 4-3 downshift; see the note on shuddering earlier; I had a 93 Ford Crown Vic once, the lockup would disengage when you were coasting (if you slowed enough) then re-engage once you got back on the gas. The 86 doesn't do that.

Maybe I just need to look for a manual tranny vehicle when this one quits.

As far as hearing the motor....don't have cherry bombs, but if I just tune the radio to AM and no station, and it picks up the engine speed just fine. Need a really loud stereo to sound like yours though :)

Hey thanks Samurai, finally got around to working on the beast. BAD vacuum leak under there, the part was $15. Made a big difference. Thanx again--

Right'o Fred.
Glad I can help people with my problems.
This is what the Internet was actually for in the beginning - collaboration.
I have more problems to post anyway :(

I am having the same problem with the shifting. The shuddering lock up and all that good bs
what if the vac isnt bad???

Shuddering shifting up from 1-2-3-4, or down 4-3-2-1 at lights? What gears are affected?

Ford AOD converter locks up for 60% of third gear and bypasses overdrive altogether. Has 2/3:1 overdrive ratio so even with 373 rears when it hits od its like running 249 rears. No way to bypass lockup. Could change input shaft and use non lock up converter.

hissing is in fact emergency brake. Two lines at base of steering column. Find noisy one. disconnect and put screw in end

hissing is in fact emergency brake. Two lines at base of steering column. Find noisy one. disconnect and put screw in end


I went high-tech and got the rubber caps.