Coolent bubbling

[kevan.gibson.9]

Lol and it's 2wd


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[great white]

Always and only 35-40 mph?

If it's only related to speed, it's driveline and not engine.

There's lots of things it could be and it's near impossible to troubleshoot something like this over the internet, but that sounds like torque converter shudder on OD engagement/lockup.

Next time it does it touch the brake pedal. Not enough to engage brakes, but enough to turn on the brake lights. The brake light switch disengages the torque converter clutches.

If the shudder stops, you've probably found your problem.

Unfortunately, the fix is a new torque converter. It's worn clutches in the converter or valve body leaking off engagement pressure.

 

[kevan.gibson.9]

Lol I will try that thank u and yea my friend showed me that if u push the brake pedal it does that is it so kinda computer thing ? And yes only at 35 to 40 Ben doin it for a year


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[great white]

Lol I will try that thank u and yea my friend showed me that if u push the brake pedal it does that is it so kinda computer thing ? And yes only at 35 to 40 Ben doin it for a year


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On a 94, converter lockup is controlled by the computer. The 4L80E transmission is all electronic controlled, right down to shifting and line pressure.

The PCM commands the torque converter lockup clutches to improve MPG. The clutches are relatively small though and wear out over time (like all things). once worn, they slip and this is what causes "shudder".

The other thing that can happen is the bores in the valve body wear over time and as they wear, fluid escapes around the valve. This results in dropping line pressure and less hydraulic force available to engage the converter clutches. This is a double whammy as the reduced line pressure can allow the clutches to slip, which wears them out faster.

The converter is a sealed assembly, so replacement it the only cure for that.

Worn valve bodies can be fixed with a kit from a company called Sonnax. Basically, the bore is reamed out and a sleeve is inserted which returns it to factory specs. The transmission is usually a good candidate for rebuild at that point anyways though.

Some people have gotten a bit more out of a converter in this condition by chucking in some friction modifier (IE: snake oil). But that's kind of "the last refuge of the damned" and only lasts a while...

Do the "brake check" and see if ti goes away before you start feeling bad or start pouring schmutz into the transmission though. There are other things it can be.

Even the brake check can indicate it is a braking problem as much as it could be a converter shudder....

 

[kevan.gibson.9]

Ok thank u very much I will! U shore seem to no your stuff hope I'm not bothering u asking so many questions


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[kevan.gibson.9]

My brake warning light is on


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[great white]

Ok thank u very much I will! U shore seem to no your stuff hope I'm not bothering u asking so many questions


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Well, I do have a wee bit of experience in the field.....

No worries on the bother. I'm just sipping my morning coffee right now before I head out to the garage to finish a car starter install....

 

[kevan.gibson.9]

Wow great to meet a mechanic that knows a lot people around here don't sound like they no anything and they always try to cheat u


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[great white]

Wow great to meet a mechanic that knows a lot people around here don't sound like they no anything and they always try to cheat u


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Lol. I'm actually just a gear head from waaaay back.

I was a mechanic once upon a time, then joined the military as a technician and eventually ended up a Flight engineer flying Search and Rescue on Choppers, which is where I am today. Managed to slip a couple university degrees and an AME certification in there along the way too. Just about ready to retire to the golden years in another 5-10. I'm hard on the back side of that hill.....

I've always kept up on automotive stuff though, it's fun as a hobby but not as a job.....

 

[kevan.gibson.9]

Wow sounds like u have had a realy interesting life sounds like a good 1 I'm working my way up now I love cars and anything to do with them so anything I can lean I take it try my best at what I got also took a couple years at a auto tech trade school a few years ago but these days everthing has change so much


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