95 Chevy Caprice transmission quirks... suggestions?

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AyWoSch Motors

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I have (among many other things), a 1995 Caprice 9c1 cleverly disguised as a Impala SS.. haha.
Anyway, its my daily driver, drive it everyday to work. Has a 262 4.3 TPI V8 and a 4L60E, both original. 150k miles.
It runs great but it shifts really funky.
Theres no slipping or anything, but it doesn't down shift, and it rarely finds 1st. It wont downshift when you step on it, or are going up hills, and it wont downshift when you stop at a light or slow down.
When it does find first, it hooks and books, launches hard, 2nd, 3rd, 4th, all work great, but when i come to a stop, it stays stuck in whatever gear it was just in. I go to take off and its in 3rd or 4th, itll go, but its real sluggish. Expectedly so. If you manually downshift it, it works, but it wont find 1st on the shifter. 90% of the time im taking off in 2nd. If i put it in neutral and rev it, or slip it to reverse and back, sometimes itll find 1st. If i shut it off and let it sit itll go to 1st. Works okay, its drivable, but its not right.

Was wondering why this might be?
I dont think its the trans "going bad", i suspect the valve body, but i dont know.
Its full on fluid, fluid is red, not brown/black. It smells like ATF, not burnt or anything. No glitter or clutch material.
If like to know whats going on and what to expect at the very least. And if it's fixable id love to know how to fix it.

What do you guys think?
Thanks.
 

Ricko1966

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Next time it does it disconnect the battery and reconnect it let me know if that resets everything. We're not stopping there but it's the 1stvthing that I want to know
 

AyWoSch Motors

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Next time it does it disconnect the battery and reconnect it let me know if that resets everything. We're not stopping there but it's the 1stvthing that I want to know
Okay, ill do that. But, alot of time, when i shut the car off, itll go to 1st anyway. How would i know if anything is different?
 

AyWoSch Motors

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I have (among many other things), a 1995 Caprice 9c1 cleverly disguised as a Impala SS.. haha.
Anyway, its my daily driver, drive it everyday to work. Has a 262 4.3 TPI V8 and a 4L60E, both original. 150k miles.
It runs great but it shifts really funky.
Theres no slipping or anything, but it doesn't down shift, and it rarely finds 1st. It wont downshift when you step on it, or are going up hills, and it wont downshift when you stop at a light or slow down.
When it does find first, it hooks and books, launches hard, 2nd, 3rd, 4th, all work great, but when i come to a stop, it stays stuck in whatever gear it was just in. I go to take off and its in 3rd or 4th, itll go, but its real sluggish. Expectedly so. If you manually downshift it, it works, but it wont find 1st on the shifter. 90% of the time im taking off in 2nd. If i put it in neutral and rev it, or slip it to reverse and back, sometimes itll find 1st. If i shut it off and let it sit itll go to 1st. Works okay, its drivable, but its not right.

Was wondering why this might be?
I dont think its the trans "going bad", i suspect the valve body, but i dont know.
Its full on fluid, fluid is red, not brown/black. It smells like ATF, not burnt or anything. No glitter or clutch material.
If like to know whats going on and what to expect at the very least. And if it's fixable id love to know how to fix it.

What do you guys think?
Thanks.
Oh, and one thing to add to that. It shifts hard from 1st to second. Slams into gear, like someone ran into the back of you. On payment sometins itll bark the tires from 1st to 2nd.
If your really on it, slams from 2nd to 3rd too
 

Ricko1966

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The reason I said disconnect the battery,don't just do it once and report,do it several times and pay attention to what happens. I'm trying to figure out of something is pis sing off the pcm. The4l60e is computer controlled. While the battery is disconnected honk the horn,turn on the lights,something just to make sure we've bleed l the power.
 

Matt69olds

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What’s fluid look like? It definitely sounds like valves on the valvebody are sticky.

As long as the transmission isn’t slipping, you might be able to fix it with some valve body work.

Order one of these 2 shift kits. The SK kit is what a lot of shops call the Jr kit. The more expensive kit has options for high performance applications. In either case, order the plate. Without a doubt, the check balls will have beat up the stock plate, sometimes the check ball won’t seal, in severe cases the check ball will get stuck in the plate, or blow tight thru it. The TransGo plate is made of much harder steel.

Once the valve body is out, carefully clean it, blow it out, make sure all the valves move freely against spring pressure. Cycle the valve with a small pick, when you release the valve it should snap back to its at rest position.

Either of those kits eliminates the Pulse width modulated converter clutch “feature”. The original 700 trans, and the first couple years of 4L60E production the converter was either on or off. The HydraMatic decided to pulse the converter, slowly bring the converter on instead of it feeling like an extra shift. It worked great for a couple years. The problem is the valve cycles a few dozen times during each converter apply. The valve and valve body bore wears, causing leakage. That can result in partial converter apply, trans overheating, check engine light, all kinds of problems. The shift kit has the parts to fix it.

It’s not too hard to install, you just need a large, very clean area. Be prepared for a transmission fluid mess. Have a small jar of Vasoline to hold the check balls in place. You need an inch pound torque wrench, a source of compressed air, small snap ring pliers, and lots of brake clean. Work slowly, don’t force anything.

There are lots of YouTube videos on installing these kits.
 

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AyWoSch Motors

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What’s fluid look like? It definitely sounds like valves on the valvebody are sticky.

As long as the transmission isn’t slipping, you might be able to fix it with some valve body work.

Order one of these 2 shift kits. The SK kit is what a lot of shops call the Jr kit. The more expensive kit has options for high performance applications. In either case, order the plate. Without a doubt, the check balls will have beat up the stock plate, sometimes the check ball won’t seal, in severe cases the check ball will get stuck in the plate, or blow tight thru it. The TransGo plate is made of much harder steel.

Once the valve body is out, carefully clean it, blow it out, make sure all the valves move freely against spring pressure. Cycle the valve with a small pick, when you release the valve it should snap back to its at rest position.

Either of those kits eliminates the Pulse width modulated converter clutch “feature”. The original 700 trans, and the first couple years of 4L60E production the converter was either on or off. The HydraMatic decided to pulse the converter, slowly bring the converter on instead of it feeling like an extra shift. It worked great for a couple years. The problem is the valve cycles a few dozen times during each converter apply. The valve and valve body bore wears, causing leakage. That can result in partial converter apply, trans overheating, check engine light, all kinds of problems. The shift kit has the parts to fix it.

It’s not too hard to install, you just need a large, very clean area. Be prepared for a transmission fluid mess. Have a small jar of Vasoline to hold the check balls in place. You need an inch pound torque wrench, a source of compressed air, small snap ring pliers, and lots of brake clean. Work slowly, don’t force anything.

There are lots of YouTube videos on installing these kits.
Ah, so you think valve body too..

I have to admit, thats one thing im kinda scared of opening up are automatic trans. Never messed with one, afraid ill screw sometbing up.
But it does look do able.

I was looking online, they sell whole, rebuilt valve bodys for 4l60e for only like $100-150. Would it better to just swap out the whole thing?
 

AyWoSch Motors

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Matt69olds

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If it’s a quality refurbished valve body, it should have all the updates done to it. I guess it depends on who you get the valvebody from.

In either case, be sure to get the plate.
 

Albrigap

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I drove an 87 9C1 Caprice from new to 150,000 miles.
These are the best driving cars in the world.
Would hit overdrive at 132 mph.
Radar verified.
What a car!
The only one better is the newer Holden version of the 9C1 with the LS engine and still RWD.
 

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