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Before I take this into the shop - I want to check what some of you experts think.
A couple symptoms:
1. When overdrive is enabled: I get a a very noticeable rumble when going in between gears (intermittently). This is especially apparent on the highway on ramp.
2. When overdrive is on/off: I'm hearing an intermittent metallic scraping sound. Definitely something within the transmission/driveshaft area. Only lasts a few seconds at most when on the throttle. Seems more noticeable when O/D is off.
I'm thinking that it symptom #1 is potentially a failing torque converter, but wondering if symptom #2 is relatable, or if I should be looking elsewhere?
This sounds like what mine was doing. More than likely the OD Servo Snap ring has broken, and the "Piston" is able to turn somewhat sideways. If it hasn't been doing it long, than it shouldn't be a big fix. You will have to drop the pan, and then drop the Valve Body. A tip on the valve body is to loosen all the bolts but one near the center. Then remove all the bolts except the tight one, then loosen it. It'll help with the drips. Once it is drone dripping loosen the bolt, and remove it, remember that your valve body is heavy The valve body holds quite a bit of fluid. The Servo bore you are looking for is in the front, passenger side of the transmission. You will need a good pair of snap ring pliers, a floor jack, and some pipe (I used pvc) to remove the old broken ring, and install a new one. Put the new ring around the pipe before you use it to jack up the piston just enough to get the old ring out. Getting the old ring out was the biggest pain for me, i had to use picks to pry it out. The more of it is broken, the easier it is to remove. Once it is out then use the snap ring pliers to put the new one in. Your 2/3 servo doesn't have a snap ring that holds it in, so It will fall out when you drop the valve body. I slightly bent out the wings to make it stay in while I put the valve body back on. While it is out you should look at it and see if the top plate of the Valve body is cracked at the 2/3 servo, many of them are. You can order a new "Tough Plate" from Transtar. I think I paid $50 for the plate, snap ring, and new gaskets. The new Tough plate comes with a nose cone to keep the 2/3 servo from cracking the plate again. I used Assembly Goo to keep the cone on during installation.
If you remove the OD servo piston you will also have to reattach the OD band to the top of the piston, so try not to take it out.
Now, that bad news. If the OD snap ring has been broken for a long time, the piston may have worn the bore (Piston is steel, Transmission case is Aluminium). If it has been worn, you will at the very least need to have the OD cylinder bored and sleeved. Mine was doing it so long that the Increased pressure from the bleed off from the worn cylinder that it caused the failure of the Forward drum. All said and done it was $2,200 for a local shop to do all the machine work and rebuild the transmission. Broken Snap ring Fixed snap ring
This sounds like what mine was doing. More than likely the OD Servo Snap ring has broken, and the "Piston" is able to turn somewhat sideways. If it hasn't been doing it long, than it shouldn't be a big fix. You will have to drop the pan, and then drop the Valve Body. A tip on the valve body is to loosen all the bolts but one near the center. Then remove all the bolts except the tight one, then loosen it. It'll help with the drips. Once it is drone dripping loosen the bolt, and remove it, remember that your valve body is heavy The valve body holds quite a bit of fluid. The Servo bore you are looking for is in the front, passenger side of the transmission. You will need a good pair of snap ring pliers, a floor jack, and some pipe (I used pvc) to remove the old broken ring, and install a new one. Put the new ring around the pipe before you use it to jack up the piston just enough to get the old ring out. Getting the old ring out was the biggest pain for me, i had to use picks to pry it out. The more of it is broken, the easier it is to remove. Once it is out then use the snap ring pliers to put the new one in. Your 2/3 servo doesn't have a snap ring that holds it in, so It will fall out when you drop the valve body. I slightly bent out the wings to make it stay in while I put the valve body back on. While it is out you should look at it and see if the top plate of the Valve body is cracked at the 2/3 servo, many of them are. You can order a new "Tough Plate" from Transtar. I think I paid $50 for the plate, snap ring, and new gaskets. The new Tough plate comes with a nose cone to keep the 2/3 servo from cracking the plate again. I used Assembly Goo to keep the cone on during installation.
If you remove the OD servo piston you will also have to reattach the OD band to the top of the piston, so try not to take it out.
Now, that bad news. If the OD snap ring has been broken for a long time, the piston may have worn the bore (Piston is steel, Transmission case is Aluminium). If it has been worn, you will at the very least need to have the OD cylinder bored and sleeved. Mine was doing it so long that the Increased pressure from the bleed off from the worn cylinder that it caused the failure of the Forward drum. All said and done it was $2,200 for a local shop to do all the machine work and rebuild the transmission. Broken Snap ring Fixed snap ring
so you don’t think it could be overdrive?
I’m pretty mechanically minded, but haven’t pulled open a tranny yet. Think I should bring it in?
If it is the OD Servo snap ring than it will eventually lead to the transmission failing. The OD servo is the end of the line, so the pump is upping the pressure down the whole line to compensate for the loss of pressure at the end of the line. My Forward drum literally came out in 2 pieces. Kinda like this.
10-01-2018, 11:46 AM
Bloody Transmission...need some pointers
