'89 Chevy Caprice Wagon Transmission

transmissions
caprice

#1

I need help guys.
Last night transmission in my beloved '89 Caprice Wagon let go, it slips completely in all the forward gears. I was coming down a long hill using low gear for several minutes and when I put it back into OD at the bottom it seemed to skip a little but it was still making power well enough. I got off the freeway at my exit and stopped at a red light, when the light changed I was reving high but barely creeping through the intersection. I pulled over and this is what I figured out:
-All the forward gears make essentially no power any more.
-Reverse seems to work normally.
-The fluid is at a normal level and not discolored or burnt smelling.

I don’t know if this is related or just an amazing coincidence but the water pump also seems to have blown the gasket at the same time. I must have just happened within a few minutes of me pulling over because there was still a ton of coolant left and the temp was still in the normal range. I don’t see how they’re related but, like I said, the timing is too coincidental. Earlier this week but just a few miles ago I also topped the power steering fluid and oil.

It’s a 200-R4 transmission, is it toast? Why does reverse work but all the forward gears slip completely? Is the water pump just a red herring? Thanks.

P.S. I did drive the rest of the way home in reverse.


#2

If you overheat the engine, you also overheat the transmission.

The tranny fluid cooler is inside the radiator.

Tester


#3

It was running in the normal range all day and was extra cool while I coasted down the hill, even after I saw the leak it never got above the middle of the gauge which is where it settles when you’re climbing a hill. I think it might be labeled 220 degrees if memory serves, is that too hot? Is 220 hot enough to burn up a clutch?

I’m looking through the service manual, the hundreds of pages dedicated to the transmission are pretty well beyond me but it looks like there is a “forward clutch” which is engaged for all the forward gear selections and a different “lo and reverse clutch” for reverse. I’m feeling a transmission replacement coming on.


#4

Then you might be talking that the transmission overheating the engine.

Remember, the tranny cooler is inside the radiator.

Tester


#5

I think the forward clutches are shot. Reverse is a different clutch. It can happen very quickly. I had my 74 cutlass parked in the ramp. It was bitter cold out and backed it out of the stall, and no forward gears. I had to back it out of the ramp and a couple blocks to a place where it could wait for a tow for an overhaul. No warning before that except 180k on it.


#6

Likely the water pump is a co-incidence. Automatic transmissions have a bunch of gears and clutches inside. The gears don’t wear out usually, at least if the routine maintenance is done on schedule and the car is driven conservatively, but even in the best of situations the clutches do wear out eventually. And when they do, they have to be replaced with new ones. This is really more in the way of expected maintenance, and the proof of this statement is that rebuild kits are available to fix this problem. Somebody already anticipated this would happen to you, and they have the kit of parts you need all together to fix it. The transmission isn’t “toast”. Most of it, it’s still serviceable. But it most likely needs to be taken apart, and the the parts that are worn out replaced, i.e. time for a transmission rebuild.

That said, there’s a chance it is something more simple. There are electrical selenoids that can fail, and these are easier to replace than doing a whole rebuild job. It’s not a thing requiring any magic. A good well recommended local inde transmission shop can tell you one way or the other.


#7

I think your transmission is gone; and this is not surprising considering the age of the car.

Are you sure that’s a 200R4? A Chevy should use a 700R4 with the 200 relegated to Buicks, Pontiacs, and Cadillacs, etc.

It might be best to drop the pan on the transmission. If the pan is full of metallic debris, friction material, or even shrapnel then you definitely need a rebuilt transmission.


#8

If the Forward Clutch is not engaging you will not have any forward transmission of power. You can still have Reverse as it uses the Direct/Reverse clutch and the Low/Reverse clutch as well as the roller clutch in the OverDrive unit between the torque converter and the reduction unit.

The fact that you have Reverse indicates that the pump and presssure regulator are working and that power is making it through the overdirve unit. If you wanted to diagnosis this further, do a line pressure check in OD/Drive selection, as well as Reverse, Reverse at stall, and all the other forward selections. See how the pressures match up to specifications. If the pressure is low in all the forward selections, you might drop the pan, and note if any valve body bolts are loose. Then remove the valve body and see if there are signs of a broken gasket. Then do an air pressure check of the Forward Clutch. If you hear air escaping and no “thud”, you have narrowed down the problem.

As to what is actually broken, it could be one of the seals on the Forward Clutch piston or a broken seal ring between the clutch drum support and the drum hub. It would not be the one between the High/Reverse and the Forward as that would show up as a problem with reverse. In any case, the transmission would have to come apart for repair so a complete overhaul should be done.

It is possible that when the Forward Clutch piston lost clamping pressure that the slipage heated the oil enough that water going into the engine started to boil. The extra hot water would enter the water pump which might be the cause of the later coolant leak. Remember that the transmission cooler is the in the outlet side of the radiator so it heats the coolest water in the circulation.

Hope this helps.


#9

I have a caprice with a 200-r4 in it. I had to have the front seal replaced and decided not to have the unit rebuilt since it functions perfectly. I wonder if your seals got cooked.