archeman Posted March 12, 2022 Share Posted March 12, 2022 I live near the Eastern Sierra Mountains that descend down to the valley in about 30 miles of rolling hills taken at highway speeds. My truck feels like it is really hurting itself slamming in and out of OD. You can feel the hits right through the chassis. I started reading (now we're in trouble!) the AOD Service Manual on this site and found this bit in the Troubleshooting section: Symptoms:Shift clunk when throttle is backed off after full or heavy throttle acceleration. Harsh coasting downshifts out of 4th gear (automatic 4-3 shifts in © range). Cause: TV Control Linkage is set too long. Remedy: Follow linkage adjustment procedure using Linkage Adjustment at Carburetor. Since linkage is long, backout linkage lever adjustment screw at least six turns before a gap develops between screw and throttle lever.If this is not the case, long linkage diagnosis is incorrect Has anyone else tried to perform this adjustment? How to verify this is really my issue and I'm not just looking for something to tinker with? Link to comment Share on other sites More sharing options...
mat in tn Posted March 12, 2022 Share Posted March 12, 2022 first of all... is this truck new to you? if not, is this symptom new? Link to comment Share on other sites More sharing options...
85lebaront2 Posted March 12, 2022 Share Posted March 12, 2022 first of all... is this truck new to you? if not, is this symptom new? Not to mention he doesn't have a carburetor, so he has the wrong diagnostic chart. Link to comment Share on other sites More sharing options...
archeman Posted March 13, 2022 Author Share Posted March 13, 2022 first of all... is this truck new to you? if not, is this symptom new? OK thank you, I see where I was on the wrong page. My symptom still matches that one described for the carb'ed AOD. Hard shifts when coming off throttle after cresting a hill and starting the descent above 55mph. The truck has had this issue for a very long time, more than 10 years but I moved out of the mountains so I wasn't reminded of the problem until I rolled it up the mountains a couple of weekends ago. I wanted to start to address some of this trucks issues since I plan on keeping it for a long time. Link to comment Share on other sites More sharing options...
85lebaront2 Posted March 13, 2022 Share Posted March 13, 2022 OK thank you, I see where I was on the wrong page. My symptom still matches that one described for the carb'ed AOD. Hard shifts when coming off throttle after cresting a hill and starting the descent above 55mph. The truck has had this issue for a very long time, more than 10 years but I moved out of the mountains so I wasn't reminded of the problem until I rolled it up the mountains a couple of weekends ago. I wanted to start to address some of this trucks issues since I plan on keeping it for a long time. Ok, on yours, the cable is up on top of the throttle body, originally under a plastic cover. A hard downshift, and probably a late, hard upshift is caused by the cable being too short. Since there is no cable adjustment, you have to move the cable casing. To effect the lengthening of the cable involves moving the outer casing toward the pin that the cable snaps on to. There is a large spring loaded section near where the TV cable attaches to the throttle body bracket. There is a large pressed in detent latch on the part that attaches the cable to the bracket. Holding the cable so it can't move back, release this latch by prying it up until you feel the cable casing want to push away from the bracket, push the casing in until you can re-latch it one notch in. This has now "lengthened" the cable one notch. Drive the truck and evaluate the shift feel, if it is good, reinstall the cover. Basically cable casing toward pin = earlier, softer shift, away from pin = later harder shift, just opposite of the carburated rod. Link to comment Share on other sites More sharing options...
mat in tn Posted March 13, 2022 Share Posted March 13, 2022 Ok, on yours, the cable is up on top of the throttle body, originally under a plastic cover. A hard downshift, and probably a late, hard upshift is caused by the cable being too short. Since there is no cable adjustment, you have to move the cable casing. To effect the lengthening of the cable involves moving the outer casing toward the pin that the cable snaps on to. There is a large spring loaded section near where the TV cable attaches to the throttle body bracket. There is a large pressed in detent latch on the part that attaches the cable to the bracket. Holding the cable so it can't move back, release this latch by prying it up until you feel the cable casing want to push away from the bracket, push the casing in until you can re-latch it one notch in. This has now "lengthened" the cable one notch. Drive the truck and evaluate the shift feel, if it is good, reinstall the cover. Basically cable casing toward pin = earlier, softer shift, away from pin = later harder shift, just opposite of the carburated rod. yes, the cable adjustment is very important. if it is too long(loose) it will apply holding pressure on the clutches later and will allow the clutch to slip. whereas if it is too short(tight) it will hold more pressure than required per the load on the engine and harsh shifting can be felt. mis adjusted tv cables have been the cause of MANY aod failures. too loose or disconnected and it will burn the clutches quickly and that is the real weak link of the aod. too tight for the most part is just uncomfortable. I try to set them where I can just feel the positive gear change and no more. That should bring in od at 40-45 mph. of course the more throttle used the later the upshift. proper adjustment requires a test gauge attached to the tv port on the rear passenger side of the transmission case. pressure reading is spec'd at 0-5 psi at idle. I go for 4-5 psi. I want as little slip as comfortably possible and downshift on tip in responsive. Link to comment Share on other sites More sharing options...
archeman Posted March 15, 2022 Author Share Posted March 15, 2022 yes, the cable adjustment is very important. if it is too long(loose) it will apply holding pressure on the clutches later and will allow the clutch to slip. whereas if it is too short(tight) it will hold more pressure than required per the load on the engine and harsh shifting can be felt. mis adjusted tv cables have been the cause of MANY aod failures. too loose or disconnected and it will burn the clutches quickly and that is the real weak link of the aod. too tight for the most part is just uncomfortable. I try to set them where I can just feel the positive gear change and no more. That should bring in od at 40-45 mph. of course the more throttle used the later the upshift. proper adjustment requires a test gauge attached to the tv port on the rear passenger side of the transmission case. pressure reading is spec'd at 0-5 psi at idle. I go for 4-5 psi. I want as little slip as comfortably possible and downshift on tip in responsive. Thank you Mat in Tenn and Lebaront I will carefully walk through that cable adjustment. I'll also provide some before and after cable position photos with behavioral results, as much for myself as the the community. Link to comment Share on other sites More sharing options...
LARIAT 85 Posted March 16, 2022 Share Posted March 16, 2022 Thank you Mat in Tenn and Lebaront I will carefully walk through that cable adjustment. I'll also provide some before and after cable position photos with behavioral results, as much for myself as the the community. I agree with what was already said: too little TV pressure and bad things can happen to your AOD quickly. If anything, err on the side of more TV pressure rather than less. But your symptoms sound like you may actually have too much pressure. I adjusted my Lokar TV cable to have a full pull of the TV cable at full throttle. It has been adjusted that way for about 7 years now and I haven't had any issues. Link to comment Share on other sites More sharing options...
archeman Posted March 28, 2022 Author Share Posted March 28, 2022 I agree with what was already said: too little TV pressure and bad things can happen to your AOD quickly. If anything, err on the side of more TV pressure rather than less. But your symptoms sound like you may actually have too much pressure. I adjusted my Lokar TV cable to have a full pull of the TV cable at full throttle. It has been adjusted that way for about 7 years now and I haven't had any issues. I found this crusty old TV formatted video that I believe describes the factory setting of the cable and I will follow that procedure. Link to comment Share on other sites More sharing options...
archeman Posted March 30, 2022 Author Share Posted March 30, 2022 I found this crusty old TV formatted video that I believe describes the factory setting of the cable and I will follow that procedure. So I got time to try this cable adjustment. I may have an issue in that I think the cable is at it's limit WRT the adjustability OR perhaps my 'idle' screw is mis-adjusted which would pull the cable too. I found that the little lock collar that is the key to the cable adjustment seemed to be frozen in place. That is because it has probably not been disturbed in decades. In the video above the guy just grabs it and the thing popped up for him but he must have had some magic fairy dust he sprinkled on it 1st because mine needed a fight. The retaining tabs are at the bottom of the collar and need to be pushed inward then the chemical bond created by dust and time needs to be broken after that. A quick drive afterwards didn't show any appreciable difference BUT didn't reveal any problems with the adjustment I made. I'll have to go drive it in the hills later. Link to comment Share on other sites More sharing options...
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