Ford AOD, AOD-E, 4R70W, 4R75 - Overdrive Servo Service Technique 

Hi Bruce, that's really up to you. Those transmissions are very finiky, especially the valve bodies. If you really like the van and plan on keeping it then it's worth it but that's your call at the end of the day. As far as no overdrive, could be the band is jist worn/shot or the servo sealing rings/square cut seals are no longer holding apply fluid (or both). If you can get the trans out and change the band (it's just behind the pump and intermediate clutch pack), then you can prob rebuild the entire unit yourself, assuming you dont have to change the lip seals on any of the apply pistons (or you can if you have the special otc lip seal tools). If you do take it out, leave the valve body alone if it's otherwise working. Same with the governor. Set them both aside in a clean, safe place until you're ready to put them back on.

@nickstransmissions Thanks for taking the time to reply, so you think it should be easy enough for a noob like me to attempt and if not it's worth bringing into a shop? I've just heard of transmissions continuing to have issues after being taken to a shop but if it's a simple enough fix for the average shop I wouldn't mind bringing it in. Thanks for replying again, I sent you a coffee!!

Thank you for the coffee, Bruce! If you're mechanically inclined then you should be able to do the job, provided that you have: 1. A clean workspace 2. Holding fixture and place to mount it for the transmission (don't try to assemble it with the unit simply standing up on something) 3. The ATSG manual - here's the online PDF version: goodshop.ukrtrans.biz/wp-content/uploads/catalogs/AOD.pdf 4. Time The only things that may give you a challenge are the bushings, especially the rear case bushing. For those, I'd outsource bushing R/R to a trans shop...Many will remove old bushings and reinstall new ones for a couple hundred bucks, provided you bring them all the parts including the case. I would recommend watching my AOD rebuild series where I show the step by step process and procedures as well as parts selection and other considerations (assuming you haven't already) so you get an idea of what's involved and how to do it...If you don't plan on replacing the lip seals in the drums and pump, then you don't actually need to take the drums apart beyond just replacing all the clutches and steels. Let me know if you have any questions...

I have the EXACT same issue on my 2008 E350 super duty (4R75E) at 182K miles. Everything is good except overdrive. If I turn off overdrive it drives and shifts normally except no overdrive. I stopped driving it initially when it started to slip/neutral out. It could be a O/D servo issue, e.g. broken snap ring. FordTechMakuloco has a RU-vid video that shows how to inspect the valve body and reinstall a O/D servo. I won’t lie doing it with the transmission in the vehicle and correctly catching the band looks a little daunting. Haven’t done it yet, I figure if I try and it doesn’t work the transmission is coming out and I’ll put a rebuilt one in there (that does not require a core) and I’ll disassemble the existing transmission and store it with a view to overhauling it myself later.

@@iamthevanavator281 Crazy, have you been driving with the od off? If so how long

Hi JHancock, thank you for watching. So the 3-4 upshift is fine but the 4-3 downshift is what is harsh? Do you have a 'constant pressure' valve body installed? The direct clutch pack clearance is likely on or past the high side of spec (the one you see in this video had almost double the amount of clearance it should have had when it came in); TV cable may also be a bit too tight (assumes you don't have a constant pressure VB). Perhaps check your line pressures at idle at min and full TV or do a stall test to see how much pressure is being generated as that should let you know if the TV cable needs to be readjusted. If you're not finding any answers there, check the 2-3 accumulator to see if it's missing a spring or spring is broken.

Transmission does not have a tv cable. I'm going to assume it's a constant pressure valve body since it's an aode, but there isn't a computer to control it. Apparently, it was built so you could shift 3 to 4 under full power. Transmission shifts hard up and down all gears. Down shifting from 4 to 3 isn't any worse than the other downshifts. If you floor the car, it's no worse than 2 to 1 downshift. But cruising at part throttle and down shifting 4 to 3 is annoying. I figured it was either the servo or in the valve body but wasn't sure where to start looking. Transmission is an Art Carr built Aode. Unfortunately, they went out of business a couple of years back (someone is currently ripping off his reputation using his name.) Thank you again for your response and the information. You are putting out very helpful videos.

You're welcome, glad the videos are helping you understand this family of transmissions. Ah, that's correct (for some reason I simply ignored the 'E' on the end of AOD in your initial comment, lol). I'm thinking Art Carr built that unit for a higher stall, perhaps street/strip type application so if you were to put something like a 2800+ converter in there, it'd shift great. But for a stock stall, it sounds way over calibrated...What you can do is drop the valve body and have a look at the spacer plate to see what was done to the feed orifices for the 1-2 and 2-3 shift (the 3-4 feed isn't a normal orifice). It could be as simple as replacing the spacer plate with a factory AODE original plate that hasn't been altered in any way.

Hi Robert, thank you for watching...I'd steer clear of anything from Monster Transmission; while they will sell you the same parts as anyone else, their mark up is significantly higher so usually not worth the money. You can buy all those same parts from Transtar for around 20-30% less, at least that was the case the last time I compared Monster's prices to other suppliers in the trade. Make sure you buy the OTC apply piston installation tools as the aftermarket ones are hit and miss.

Ok thank you

Being my first time attempting to overhaul this aod what. Special tools should I buy to do this job thank you for your help

Here you go: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-PLcdSSg5ogc.html

I do a visual inspection, looking for obvious signs of wear (oblong bore, gouge marks/scoring, etc...I'll also take a servo pin that's in good condition and insert it into the bore to see if there's an unusual amount of play...Another indicator is the band and to some extent, direct clutch...If the bore for the OD servo is warped, burnt bands and stressed direct clutches can result. Sonnax makes a sleeve that you can insert once you ream the bore out to a slightly oversize dimension though I don't have the special tools they make to do it; haven't yet come across one that actually needs it but can't say how common or not the problem is...Sonnax instructions for it can be found here: d2q1ebiag300ih.cloudfront.net/uploads/part/2386/76890-24K-IN.pdf?v=1638309088552 Thanks for watching, Mike!

Here you go: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-vB2uMuyQ9L0.html

@@nickstransmissions that looks great. Do you have any tricks and getting the cover off? Something to hold it down while I remove the snap ring?

All that is in the video; you can also improvise by using a large wooden dowel of the right length that compresses the cover via using the floor and weight of the entire vehicle.

Bottle jack and rod or punch works well also; I'm assuming you are trying to do servo work with the transmission in the vehicle..If it's out on the bench, just watch the video as everything you need to know is in there...

@@nickstransmissions yes, it’s on the bench. I’ll check out the vid