I just picked up this 73 Riv for 500$. I didn't have time to fully test drive it, so it was a quick run in the drive way of the of the shop where it was sitting at. The manager said it ran fine, but he had as I did, noticed how it slipped in reverse, it wouldn't transfer the power. But he assured me it was tight in all forward gears. Well I get it and start to drive home, and the car never reaches second or third, or it does, but I don't notice it. If you run it in "1" you get the engine push back as you let of the gas. If you run it in "2" it rolls when you let off, no push back but it has never shifted to 2nd. If you run it in "d" it's the same as "2" and you go through 1st and you hear it trying to do some kind of shift, but it comes out like a sneeze with some clink noise, and you let off and it's still in 1st. The car doesn't want to change gears. If you get it rolling in "d" and you want to get back on the gas there's no response throught the tranny, it will rev, but not accelerate. The guy seemed decent and he was convinced it shifted good. (Or a good liar)They have been in the transmission to fix a leak, and it is now way overfilled if you look at the stick, could this be part of it, or is it toasted? Any troubleshooting tips? I drove it home through slow traffic so there wasn't much need for the shifting anyway, but I'd like to get it up and running. I don't know too much about the car, could have been sitting for quite dome time?? If I would need a new transmission for it, or rebuild the existng one which I'm not to interested in since it was a 500$ car, which cars would have a th400 that would fit that I could chance it on in the yard? how tricky is it to take out/put in transmissions? Something you can do in you back yard, or a real pain. If you have any specific questions on the diagnose I'll try to answer them as good as I can, hopefully we can sort this one out, without having to replace the 400. Where do I begin? Many thanks for your help..
The transmission sounds like it is on it's way out, but you might as well check the basics. If the fluid is overfilled, see if you can siphon out the extra fluid. Sounds like they changed the fluid to fix the leak, so you really don't know how the old fluid looked or felt. Check the vacuum modulator. Make sure it has a good, leak free vacuum supply. Also, remove the modulator, and test it with a mityvac or equivalent. Does it hold vacuum? You can also remove the governor, and make sure the valve moves freely, and it's not gummed up. The hardest part of transmission removal/installation is dealing with the bulk and weight of the transmission. I recommend you get help from a friend if you decide to do this yourself. Get the car as high as you can on jackstands. They make attachments for floor jacks that will mount to a transmission, and it makes the job much easier. Get one of those inexpensive plugs that fit in the tailshaft. If you don't you'll spill most of the fluid in your driveway. Any short tail, BOP THM400 will work, you just have to transfer your speedo gears from one trans to the other.
73 Riviera is a long tail trans (actually a medium tail, but commonly called long tail), so a short tail won't fit. If it is the original trans coded 73BC or 73BT, don't toss the tranny as it has a very good valve body in it. Mark
Is there a code stamped somewhere to make sure which one it is? Thanks for the input, I'll see what we can do to it. It's jst surprising that the guy who sold it would stand there and say it shifts tight in all three forward gears after I've already paid him a few days earlier. He must have believed it himself, could they have messed something up while working on it? This is what their print out said from the work they had done: Remove trans pan, replace switch leaking. I'll give them a call on Monday to see if I he would have any additional info on it. If it's "long tail" which cars would have one of those? or "short tail" ???
You likely won't find much unless you drop the pan. The switch that could have been replaced is the TCS (transmission Controlled Spark). It is attached to the valve body and energizes when 3rd gear oil pressure is applied. It then sends a signal to a switch on the carb that has vacuum hoses to the distributor allowing vacuum to the advance. The switch may have been leaking, which would cause the trans to slip in 3rd and reverse. Sounds possible from what you described. This should not be related to the problem you are now having as the trans would only slip in 3rd gear. It sounds like they messed up installing the filter or used a poor quality one which is restricting fluid flow. Filter problems would cause the trans to slip all the time and not shift into higher gears. The filter attaches to a plastic pipe (early ones were metal, but 73 should be plastic) that goes into the case and filter. If they tore the "O" in the case side, it would suck air. Sometimes, mechanics screw up and put the pipe in upside down. This will cause air being sucked in as well. Looks like you need to pull the pan and take a look. As to identifying the trans, there should be a metal tag on the passenger side which has the year/code on it. Should be painted a faint red (may look pink) and have the codes in it. If the paint is worn off, the codes are stamped at the bottom of the tag. Sometimes, the tag is missing. Most times it is there. Short tail trans' are used primarily on "A" body big block cars. GS's, Gto's, 442's and chevelles. The longer tail ones are normally in full size cars. 69-76 and up Electra/Wildcat/Centurion/Riviera (71-76), Bonneville, Olds 98 etc. This should give you something to go on. Good Luck, Mark
Many thanks for the help... Enlightenment is always good on the unknown. I saw that the vacuum hose coming down from the carb is completely off at the transmission, I'll have to get that replaced and see what happens. Keep your fingers crossed..... If that doesn't work, it will be taken back in behind the house and the pan will come off. They said they fixed the pan leak but there's of course a puddle under the tranny.. I don't think I'll ever take my car in to a shop again, I wonder how they get away with doing shitty jobs all the time, or does this only relate to me?
That's a big problem right there. The vacuum modulator needs the engine vacuum signal. Another thing, the vacuum takeoff is not at the carb, it is right off the back of the intake manifold. There should be a metal vacuum line that has rubber lines at both ends. one side goes to the intake manifold fitting, the other goes to the modulator. Fix that first before you do anything. The vacuum modulator must see manifold vacuum at all times. The fitting for the modulator is right above #8 in this picture
