Have a 90 SC shes got 120000 this is my second SC She has a tranny issue wondering if its toast . it shifts great 1 2 cant get her to 3rd or OD the guy I bought it from said it happened after he had the fluid changed at oil can henrys. was thinking about taking the pan off is there anyhting for me to look for except for the obvious shavings. if shes bad and just 3rd and OD can I just rebuild those 2 gears. Im sure i can do it myself just need a tranny expert to school me a little thanks for the info in advance
Aod Toast?
- Thread starter shawpdx1
- Start date
Need more info...
What do you mean by you can't get it to shift to 3rd or OD? Does it act like you shifted to neutral (slipping and high rev), or does it continue to wind out in 2nd? If it slips, then check the fluid level first (it should be filled up to the stamped lettering that says "Do Not Overfill" on the dipstick). You should also check the Throttle Valve (TV) linkage at the throttlebody. If the linkage is too loose (TV pressure too low) this will cause shift problems (gear stacking) and trash the tranny. If it is too tight (TV pressure too high) it will cause delayed shifts. If the tranny just winds the engine out in 2nd without shifting to 3rd, the pressure may be too high. There are write-ups on how to temporarily set the TV pressure by the "no-slack" adjustment, but it is best to get it set properly with a guage attached to the TV pressure fitting on the side of the tranny (passenger side, right by the cooler lines). Drop the pan and look for debris. If you find a lot of glitter (metal flake), you are probably looking at a rebuild. If it just has some sludge, change the fluid and see if that improves things.
What do you mean by you can't get it to shift to 3rd or OD? Does it act like you shifted to neutral (slipping and high rev), or does it continue to wind out in 2nd? If it slips, then check the fluid level first (it should be filled up to the stamped lettering that says "Do Not Overfill" on the dipstick). You should also check the Throttle Valve (TV) linkage at the throttlebody. If the linkage is too loose (TV pressure too low) this will cause shift problems (gear stacking) and trash the tranny. If it is too tight (TV pressure too high) it will cause delayed shifts. If the tranny just winds the engine out in 2nd without shifting to 3rd, the pressure may be too high. There are write-ups on how to temporarily set the TV pressure by the "no-slack" adjustment, but it is best to get it set properly with a guage attached to the TV pressure fitting on the side of the tranny (passenger side, right by the cooler lines). Drop the pan and look for debris. If you find a lot of glitter (metal flake), you are probably looking at a rebuild. If it just has some sludge, change the fluid and see if that improves things.
garsc
Registered User
You stated this occured after it went for a fluid change. Too many times I have seen people take a car in for a fluid change thinking it will fix thier problems its usually too late by then and seldom works. I have seen fluid changed on cars where the tranny was functioning properly and after the fluid change the tranny began to malfunction, probably by disturbing debris already in the tranny.At any rate what you describe looks to me like an internal problem needing a rebuild. When you repair one of these trannys the prudent thing to do is a total rebuild.
slowpoke
Registered User
just a thought,i dont know to much about the aod's, if its anything like a 4l60e then it uses an electric valve body to shift and its possible that a wire might have come off or broke. as far as the part where you asked(can just those 2 gears be rebuilt) sorry to make your day bad sadly no. if any gear clutch ext goes out in an auto tranny then your wasting your money if you dont rebuild the entire thing and make sure to get a new converter. u can save some money by having the old converter flushed but then run a 50/50 chance that it will blow your rebuilt tranny. its better in my opinion to just get a new converter. keep in mind to this might be the excuse u need to install a stall converter, say around 2800rpm stall
garsc
Registered User
AOD trans arent electrically controlled so that isnt going to be the problem.When rebuilding one of these the smartest thing to do is hane the cooler and lines flushed and replace the convertor with a new or reman unit. These convertors are a weak link and prone to failure anyway so why take chances. I am glad mine is a 5 spd or I would convert it to a C4. It is a much stronger trans but you miss the overdrive. Ran one in my drag car for 8 years behind a built 302 with no problems.
Ddubb
Registered User
I just bought a 1991 Tbird with a 5.0 Engine and AOD transmission recently, got it for cheap becasue the owner said it had " Tranny problems " .. took it for a test drive, and it wouldnt go over 50 mph .. the rpm's just climbed and it didnt shift gears.
I figured I would need to rebuild it, but I went to check the TV cable and it wasnt even attached to the Throttle body linkage. The grommet was missing and the TV cable was just sitting there. So I took a zip tie, hooked it up, took it for anoter drive, and hit 70 mph no problem.
May not be your problem .. but keep it simple, check the TV cable first, then move onto considering a rebuild.
- Dan
I figured I would need to rebuild it, but I went to check the TV cable and it wasnt even attached to the Throttle body linkage. The grommet was missing and the TV cable was just sitting there. So I took a zip tie, hooked it up, took it for anoter drive, and hit 70 mph no problem.
May not be your problem .. but keep it simple, check the TV cable first, then move onto considering a rebuild.
- Dan
Yeah I have a 92 5speed also bought this one a year ago and she's been sitting so I thought I would monkey with it. I have 2 cables coming off the throttle body lower one I would guess is for downshift? the upper cable didnt have the rubber gromit in it either I zip tied it myself but still can get it to shift out if second its about half way down the shaft (the cable) shifts great from 1-2 real smooth runner I kinda like the idea of not shifting all the time just jump in the auto and go. anyway I think she's gone were should the cable be sitting all the way up so its tight? I think I'll pull the pan this weekend . how hard are they to rebuild how much is the kit? thanks guys
Ddubb
Registered User
You have 2 cables ?? Does your car have Cruise control ?? The Cruise and Throttle are attached to eachother .. so there should actually be 3 cables off the throttle body linkage.
The TV cable should be on the upper most one. Your adjustment could be bad .. especially if you have it zip tied .. sounds like my Tbird - but that was just for testing purposes. You'll want to adjust it correctly .. driving with it out of adjustment can fry your transmission if it isnt already damaged.
- Dan
The TV cable should be on the upper most one. Your adjustment could be bad .. especially if you have it zip tied .. sounds like my Tbird - but that was just for testing purposes. You'll want to adjust it correctly .. driving with it out of adjustment can fry your transmission if it isnt already damaged.
- Dan
Read through the following stuff. These guys really have their stuff together.
http://www.becontrols.com/ourfaqs/aodtroubleshoot_1.htm
It may give you some low buck tips if it isin't fried yet. If it were me, I would pull the pan, and get to the 2-3 accumulator and check the bore/seals. Also, check the TV linkage inside the trans (barring you already checked it at the TB).
Unfortunately, Your situation sounds much like the following Q, hope it isint.
http://www.becontrols.com/ourfaqs/aodtroubleshoot_2.htm#03074204
aaaand
http://www.becontrols.com/ourfaqs/aodtroubleshoot_1.htm#09099088
my $0.02
-dz
http://www.becontrols.com/ourfaqs/aodtroubleshoot_1.htm
It may give you some low buck tips if it isin't fried yet. If it were me, I would pull the pan, and get to the 2-3 accumulator and check the bore/seals. Also, check the TV linkage inside the trans (barring you already checked it at the TB).
Unfortunately, Your situation sounds much like the following Q, hope it isint.
http://www.becontrols.com/ourfaqs/aodtroubleshoot_2.htm#03074204
aaaand
http://www.becontrols.com/ourfaqs/aodtroubleshoot_1.htm#09099088
my $0.02
-dz
Last edited:
sizemoremk
Registered User
I still don't understand if it is shifting into 3rd, then free rev or never shifting out of 2nd.
So does it just stay in second and RPMs continue to climb? Or does it shift into 3rd and free rev?
If it is shifting, then free spinning, then it can be either a snapped input shaft, or a bad direct clutchpack.
I snapped my input shaft with only a few mods, but I did have a BEcontrols shift kit. I have since replaced it with a hardened input shaft.
The split input shaft design is weak, the 3rd and 4th gears are both tied from the direct clutchpack to the converter housing itself. Basically the input shaft is tied directly to the crank at all times and is only in lockup when the direct clutchpack is engaged (FYI, 1 and 2 donnot lockup in an AOD). So the logical place to look is at the input shaft and direct clutchpack and/or the circuit going thereto.
There is no clutch in an non electronic AOD. Our 89-93 SCs are non electronic AODs, the 94+ SCs have 4R70w trannies (those are AOD-E with wide ratio gearset). So since there is no clutch in an AOD TC I have reused stock AOD torque converters several times with no ill effects, i just flush them for quite awhile in a solvent tank. Though you can get a remanned unit for about $125.
Look through the becontrols website, lots of good info there. I used their services and purchased things through them before. I would highly recommend their shift kit and hardened input shaft. They also don't have a bad price on rebuild kits.
I have also read that AODs are sensitive to valvebody torque, so use a torque wrench, and insure the correct length bolts are used in the right places, there are long and short bolts that go in specific places. The haynes book actually maps them for you. The Haynes manual for the AOD is actually quite good and is VERY similar to my ford shop manual and an ASTGE manual I come across as well.
I would probably rip the VB out first and ensure all the valves move and that its not filled with gunk; and bolt her back up. I'm not that lucky, but you might be.
If the input shaft happens to be broken, they usually break very clean and leave no shavings. You can pull it right out and put in another shaft. They usually break off at the splinned section, so it will liekly be left in the TC and you might need a magnet on a stick to get it out. You could just replae the shaft and leave the rest alone. If thats not your problem then rebuild is probably required.
However, if I went trough the trouble of removing a tranny I would go ahead and rebuild it anyway. The kit is ~125 bucks for a stock rebuild from Autozone. I have purchased rebuild kits form autozone and from becontrols, both were from the same manufacturer. I just bought one from BEcontrols, since they were extrememly helpful when I first started working on the AOD. You'll need a set of snap ring pliers from harbor freight or autozone and some mylar sheets to help get the pistons back in (mylar sheets or something like transparency paper for an overhead projector will work); OR I suggest to make things easier, you can take the clutchpacks and pistons with new seals to a hole in the wall tranny shop and get them to use their tools to assmeble them in 2 minutes for somewhere around $5-$25.
I've done 4 AODs now (one just because it was already out of the car) and have had good luck with 3 of em (the 4th is to be installed in the wifes 69 mustang in the near future). So it is not extremely difficult, just tedious. I'd take lots of pics with the digital camera for reference as I'm tearing down.
This is of course assuming that you've verified the TV cable is attached and adjusted correctly.
I'd be glad to help if I can...
Good luck!
So does it just stay in second and RPMs continue to climb? Or does it shift into 3rd and free rev?
If it is shifting, then free spinning, then it can be either a snapped input shaft, or a bad direct clutchpack.
I snapped my input shaft with only a few mods, but I did have a BEcontrols shift kit. I have since replaced it with a hardened input shaft.
The split input shaft design is weak, the 3rd and 4th gears are both tied from the direct clutchpack to the converter housing itself. Basically the input shaft is tied directly to the crank at all times and is only in lockup when the direct clutchpack is engaged (FYI, 1 and 2 donnot lockup in an AOD). So the logical place to look is at the input shaft and direct clutchpack and/or the circuit going thereto.
There is no clutch in an non electronic AOD. Our 89-93 SCs are non electronic AODs, the 94+ SCs have 4R70w trannies (those are AOD-E with wide ratio gearset). So since there is no clutch in an AOD TC I have reused stock AOD torque converters several times with no ill effects, i just flush them for quite awhile in a solvent tank. Though you can get a remanned unit for about $125.
Look through the becontrols website, lots of good info there. I used their services and purchased things through them before. I would highly recommend their shift kit and hardened input shaft. They also don't have a bad price on rebuild kits.
I have also read that AODs are sensitive to valvebody torque, so use a torque wrench, and insure the correct length bolts are used in the right places, there are long and short bolts that go in specific places. The haynes book actually maps them for you. The Haynes manual for the AOD is actually quite good and is VERY similar to my ford shop manual and an ASTGE manual I come across as well.
I would probably rip the VB out first and ensure all the valves move and that its not filled with gunk; and bolt her back up. I'm not that lucky, but you might be.
If the input shaft happens to be broken, they usually break very clean and leave no shavings. You can pull it right out and put in another shaft. They usually break off at the splinned section, so it will liekly be left in the TC and you might need a magnet on a stick to get it out. You could just replae the shaft and leave the rest alone. If thats not your problem then rebuild is probably required.
However, if I went trough the trouble of removing a tranny I would go ahead and rebuild it anyway. The kit is ~125 bucks for a stock rebuild from Autozone. I have purchased rebuild kits form autozone and from becontrols, both were from the same manufacturer. I just bought one from BEcontrols, since they were extrememly helpful when I first started working on the AOD. You'll need a set of snap ring pliers from harbor freight or autozone and some mylar sheets to help get the pistons back in (mylar sheets or something like transparency paper for an overhead projector will work); OR I suggest to make things easier, you can take the clutchpacks and pistons with new seals to a hole in the wall tranny shop and get them to use their tools to assmeble them in 2 minutes for somewhere around $5-$25.
I've done 4 AODs now (one just because it was already out of the car) and have had good luck with 3 of em (the 4th is to be installed in the wifes 69 mustang in the near future). So it is not extremely difficult, just tedious. I'd take lots of pics with the digital camera for reference as I'm tearing down.
This is of course assuming that you've verified the TV cable is attached and adjusted correctly.
I'd be glad to help if I can...
Good luck!