AOD rebuild transmission acting up

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Superbond

Well-known member
Joined
Sep 6, 2017
Messages
129
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Location
Thunder Bay
My Car
72 mustang
Here we go again!
Just took the car out for the second time after the rebuilt AOD transmission was installed 2 months ago.
And again the car once in drive start to over rev like it’s in neutral!
Had a pressure tester on it and had it setup at 36.
I may have driven 1 mile in total.
What might be wrong and did I drive it far enough to screw up the transmission?
 
When you say 'over rev', do you mean the trans feels like it's slipping and takes more rpm to get going (trans problem) or is the engine running at a higher rpm in drive while sitting still, no foot on the pedal (highly unlikely to be the trans, probably a linkage issue)?
 
I mean while driving. As I get the speed up to around 30-35 mph and it’s like I slipped it into neutral.
I had the tv cable set at 36psi with that spacer. And when the spacer was taken off the tv cable it read 0psi. From watching YouTube videos and reading posts. This is ideal.
Transmission fluid is just in the checkered marks which is good.
I’m worried I’ll have to pull the transmission and have this guy redo it. I k ow it couldn’t be from me as I did as all the posts and videos said. The install went perfectly. Torque converter was installed by the transmission guy( held in the proper position with a wrench bolted to the bell housing.
 
Did you record the psi readings for each gear selection?
I'm not up on AODs, but I just swapped out a 700r4 and had to sort some issues. After adjusting the throttle valve cable, I had to take pressure readings in each gear selection at 1k foot on brake, not driving) and a couple at 2k.
This is all according to the FSM.
I ended up with low pressure in manual 1 and 2, but the fluid path is different than D or OD, so I can ignore it or fix it when I feel like it.
 
you know that is something I never heard of. I did the test when the transmission had been warmed and in neutral
 
I did talk to the guy who rebuilt it. He said “don’t drive it until I come”. I haven’t heard from him since that reply yesterday.
Just assumed he would have called me today. I’ll give him until next weekend and if I haven’t heard from him I’ll call him. I really hope I don’t have to pull the transmission out again.
 
I've had similar problems with my conversion....made me wish I kept the C6 as there were ZERO problems with it. Upon initial installation, my AOD would not shift out of first gear. Granted, the engine build took three times longer than I had anticipated but I had taken precautions with the AOD according to the instructions from the rebuild vendor because the AOD sat in my garage for three months. Anyway, rather than go thru the motions of removing the tranny and shipping it back to Florida, I decided to take to a local AOD expert. The pump was bad and a few other parts had to be replaced. Driving it home was an aggravating adventure. There was a delay shifting into third and downshifting from third had skipped second gear and right to first damn near throwing me thru the windshield. I was fuming. I took it to my local speed shop but on the way there the shifting had improved significantly. I was confused. The downshift was still weird but the upshifts seemed fine but few more trips out and the downshift problem all but disappeared. I then began to have idle issues. it was stuck on fast idle (1500 RPM) .You might think what the heck does idle issues have to do with TV cable settings. When I installed the my new engine build with tranny, the tranny came with the Lokar TV cable system. The install of the Lokar cable went well and I also installed a Lokar throttle cable. Anyway, back to the idle issues...... My idle would not come down from fast idle now matter how long the engine warmed up. I thought that my new Edelbrock 750 CFM carb was on the fritz. Took it off and had a friend disassemble and inspect it since my 59 year old eyes are not particularly useful when dealing with small parts. He cleaned and tested it and found nothing wrong. I reinstalled the carb and then set the TV cable for 36-37 lbs of pressure but the idle was still high. I disconnected the Lokar throttle cable since it was frayed going into the connector that attaches to the carb throttle lever. It all moved freely. I then disconnected the Lokar TV cable and noticed that the cable was also frayed and bunched up inside the cable sleeve. Therein was the problem. The frayed TV cable in the sleeve was preventing the throttle lever on the carb from returning to idle. With the TV system on the AOD being so tempermental, I would not put it past anything that carb settings have to be near perfect and the cables, even though brand new, have to be inspected and checked for free range of motion. I ordered a new Lokar cable and replaced it. Works great but the Lokar throttle cable went into the trash and I purchased a new repro stock throttle cable with the integral spring. It all works great now.....except for the carb. VERY hard starting all of the sudden! Gremlins, Gremlins, Gremlins!!! Check that your throttle and TV cables are working without obstruction......
Ordered a Holley Sniper, Holley/MSD Distributor and Aeromotive Stealth gas tank with built in electric fuel pump. Ka-Ching!!
 
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Nothing quite like having the factory service manual to match your transmission. Even if you can't fix it, it helps for troubleshooting. The internet is only as good as the people posting on it. I found lots of info on line pressure for my 700r4....most of it was incomplete or for a different spec version. The FSM that matched my trans calibration (there are dozens) had all the pressure specs and rpm testing points for each gear. Even the 'pro' youtube videos only showed a general 'how to' with no step by step and nothing on the variations in factory pressure specs.

In my case, it helped me figure out that my problem was in the valve body and if I decide to fix it, I don't have to pull the whole trans out.

Like I said, my experience was with a GM 700r4.
 
I too have the same issue with the Lokar TV cable. Cut it because it was too long and it started to unwind. They should warn you NOT to cut it or at least give you an end to install on it before you cut it.
Did you have to buy the whole kit or just the cable?
 
I’m thinking it was a bad pump because he called me over to show me that all the clutches were like brand new. Still had part numbers marked on them. Maybe he didn’t test the pump or pumps. I don’t know transmissions. That’s why I paid him. I should have just installed it and ran it. It had been sitting out in a field for years. Thought if it was all good at least I’d get new seals and gaskets
 
That can happen. Automatics are domething of a magic box. One little thing, a seal, a burr, a sticky valve is all it takes.
 
Here we go again!
Just took the car out for the second time after the rebuilt AOD transmission was installed 2 months ago.
And again the car once in drive start to over rev like it’s in neutral!
Had a pressure tester on it and had it setup at 36.
I may have driven 1 mile in total.
What might be wrong and did I drive it far enough to screw up the transmission?
I ended up boosting our AOD Throttle Valve Pressure to 39 PSI to get our AOD we transplanted into our 73 Mach 1 to increase the road speeds at which the 1-2 and 2-3 upshifts occurred (and the 3-4/OD upshift). A little added pressure won't hurt anything, but too little pressure will cause problems. Increasing the TV pressure may not solve the problem you are seeing, but it may be worth goosing the TV pressure a bit to see.

In your description you mention slipping in "drive," but I could not tell if you meant 3rd gear direct 1:1 "drive," or the 0.67:1 "OverDrive drive" gear when the slipping was happening, In a later comment it sounds more like when you are "at speed" (30 - 35), when you should be in OD. If that is correct it is entirely possible the OD band needs to be adjusted. See:

https://www.therangerstation.com/forums/index.php?threads/aod-band-adjust.145388/

An aside, I never rebuilt, much less worked on, an AOD, as by the time they were coming out I had migrated into corporate White Collar America, providing computer solutions to car dealers. But, I can tell you this... With the C4, C5, FMX, and C6 transmissions I preferred to adjust bands with the tranny at normal temperature, just to make certain I was not leaving the adjustments a little too loose or tight by only bench adjusting the bands with a cold tranny. Any time I burnt smelling fluid, or a slipping transmission, I would replace all the ATF, including draining the converter, replace the filter, and adjust the bands once the tranny was filled with fresh ATF (the correct type of fluid). Unless the rubber seals for the servo or clutch pack units were hardened and leaking internally, or the valve body had a problem, in the majority of cases the band adjustment is what made all the difference in how the tranny worked. And, often it was a loose band adjustment that allowed the fluid to become burnt. Of course, if someone drove their car too far with a loose band, and the ATF just got more and more burnt, the fluid and Band Adjustment approach would be futile. But, I was working on mostly newer cars at a Ford dealership, so often I caught the transmissions with loose bands in enough time to be able to breath new life into them with new ATF and a band adjustment. For C4s I had a few little tricks with the valve body I would do that improved the crispness of their upshifting, preventing the little bit of band slippage in the 1-2 upshift that was meant to soften the upshift feeling for the comfort of the driver. I always felt that little bit of "slippage by design" did more to cause problems than it was worth.

If your problem persists, and I suspect it might (but I hope the band adjustment takes care of it, or the TV pressure bump), it would be a good time to get a technical manual that covers AOD diagnostics, and use the oil pressure ports, with oil pressure gauge(s), and see if you can identify the problem through hydraulics pressure at the time of the slippage.

Personally, I am absolutely thrilled with the AOD we swapped into our Mustang, especially with the impact on engine RPM at highway speeds with our 3.5:1 TractionLok rear axle gear set. But, in retrospect were I to do this project again I would have opted to use a 4R70W, or even AOD-E, tranny with an external electronic controller, as it would have been far easier for me to manage the various upshift speeds for the 1-2 and 2-3 (and 3-4) upshift points. Further, allegedly the 4R70W is a more rugged, stronger transmission than the earlier AOD and AOD-E units. We are fine with the strength of the AOD with our 360 HP 351 engine, as reportedly the AODs can handle 450 HP in stock form, and upwards of 600 HP with some upgrades. We do not race the Mach 1 on the streets or on track. It is just a cool cruising machine. So, the AOD ought to work out nicely in the long run for us. The external oil cooler, and use of high quality synthetic transmission fluid ought to help in that regard.
 
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I too have the same issue with the Lokar TV cable. Cut it because it was too long and it started to unwind. They should warn you NOT to cut it or at least give you an end to install on it before you cut it.
Did you have to buy the whole kit or just the cable?
I cut both cables to shorten them. They both started to unwind. I clipped the ones on the throttle cable to make it look neater but the ends are like needles a they poke the hell out of you if you have to make adjustments. I had to buy the whole cable kit because Lokar does not provide just the cable as a single replacement part. When I pulled the old frayed cable out of the sleeve, it was a little difficult. The new cable fed in without trouble so the sleeve was not damaged.
 
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