I have a 1989 Bronco XLT manufactured in May of 1989 with an AOD transmission and the 5.0 V8. The transmission has given me a lot of trouble and has been rebuilt twice. The main problem that I've had that resulted in the two rebuilds was that it would pop into over drive at high speeds. This results in what feels like a hard hit for the tranny which obviously is not good for it. This sort of thing also happens fairly regularly whenever the tranny decides to shift when coasting to a stop or down a hill. First of all this is annoying and can't be normal, but more importantly I am worried that this is damaging the drivetrain. I have read about the differences between AOD and the E4OD trans that came in later model broncos and the E4OD seems to be the superior of the two, especially with it's overdrive lockout. Ok so the Question...would it be possible to replace an AOD transmission with an E4OD transmission in a 1989 Bronco? Any ideas on how or if this can be done would be appreciated. Also...if you know anything that might be wrong with the current trans and/or anything I can do to help it would be greatly appreciated. I love the truck but can't stand the tranny or thought of blowing more money on a weak transmission. Thanks for your input.

 

I have had an 89' With the same set up as you, and now I have a 90' with 5.8L engine & E4OD trans. I have had my trans rebuilt twice in the two plus years that I've had this rig. I have also heard other people on this sight having problems with there E4OD tranies. The E4OD tranny's are all electronically controlled by the computer and a few other sensors. Not only that the computer for the 89 will not be able to control the shifting of the E4OD. One thing you might want to check out , is that there are a few aftermarket companies that might be able to sell or rebuild your AOD trany to be pretty much bullet proof. At this time I don not recall who.

Hope this helps

 

yeah the last post tells alot, you would need to get a 1990 or newer EEC computer and wire harness for your engine, along with the customization to the crossmember. not to mention that youll have to shorten your rear drive shaft about 3 inches due top the E4OD beeing much bigger.

 

I htought i should add. that i was thinking about doing the same thing, but for the price of a rebuilt E4OD, you can get one of Art Carrs buillet proof AOD's that are ment for 700 horse motors and towing 12000 pounds! then you can also get less radical trannys for around 1500. still priciy i know, but it seems like a better option to me.

 

Forget about the tranny swap. The E4OD is a POS. I bought a 95 T-bird brand new and took it back to the dealer 3 days later and told them there was something wrong with this tran. They checked it out and said all is ok and that's just how these Electonic trans are. Well, it went out at 66,000 miles! $1500. I've got the AOD in my 86 f150 and it went 168,000 before it went out. $1050. I know what you mean about the clunk when shifting into OD.
I don't drive around town with the shifter in the OD position. Just put it in Drive, not Overdrive. Only but it in OD when doing highway driving. This will keep the thing from unnessecary shifting.

 

also if there is a clunk when it upshifts you could have a bad ujoint or your pinnion yoke is loose. also might check your tcase for possible slack that could cause that. as far as the motor downshifting when you come to a stop a good tranny should do that , it helps your brakes last longer. just like with a man tranny, u drop a gear and us the tranny to slow you down before stopping. and like dharry said only use od when driving above 55 and you should be fine.

 

D Harry,
Your '95 T-Bird would not have had the E4OD tranny. You probably had the AODE.

 

To all:

Thanks for all the replys to my question. It does seem like try a switch would be A) too much work and B) might not be the best tranny to switch to. I have been driving around under 55 in drive and only using the overdrive for the freeway. I like the idea posted about a bullet proof rebuild...but that would have to wait for funds. I'll also check the joints on the drive train...it does make sense that, if there was a little play in the joint, during a shift it would compound the thump that I hear and feel. Two other ideas occured to me, is it possible to lock out the down shift at high speeds so that if you were going 75 and came to a hill while on cruise control it would not automatically try to wreck your tranny? And also, has there been any success with automatic to manual conversions...if so is it a difficult switch, is it a smart switch, and which transmissions are recomended? Thanks a lot for the previous responses to my question...cleared up a lot of questions.

 

you should not be using cruise while going up hills period. just not a good idea. by the way could you fill out your sig with some info of your rig. because for instance. what size tires are you running on your rig right now. is it lifted? info such as this helps us help you.

late

 

Mr. Wizard, you are probably right. I'm confusing the earlier tran with the later one. All I know, I didn't like it when I bought it, changed the tranny oil at 30,000 and at 60,000 and it went out at 66,000! It just didn't shift like the older fords do, nice and solid. Kind of just slushed into gear, and you can forget about making a 3 point turn around in traffic. Takes forever to go into gear! One of the FixOrRepairDaily mistakes, along with where they put the half-size oil filter on those 4.6liter V8s. Good day, Wizard.
Harry

 

Well since you are bringing up swapping to a manual trans. i have been giving this alot of thought myself. there are many different trannys that will work. the conflict that i have found was that i want it to be a 5 or 6 speed (i have seen them!) and for it to be a much more HD trans(IE, came out of a f250 or 350, no f150 trans). like i will be putting it behind my new 351. now in your case it could be much easier due to the M5OD trans. it was ment to be behind the I6's and 302's, i herd that they are decent. but dont work well under heavy load. what i am shopping around for is a ZF 5 or six speed trans with 4x4 adaptor, wich i might add, is quite rare

 

Joey, is that Marysville, WA? Check out www.valuparts.com. It is kind of like a junkyard search engine. Just for grins, I checked my local area (Vancouver) and found 3 junk yards in Portland that came up when I searched for a ZF 5-speed.

 

oh hmmmmm youd be right! thanks for the site

 

accually i had only just started to search for that trans then kinndof gave up do to lack of time and my friends word that they are rare, nice to see that there are a few roming around!

 

just joined this forum cause i am a new owner of a 1990 ford bronco full size and i am having kinda the same problem. mine does that same thing but makes a grinding noise when shifting out of second or third gear until i let off the gas a little then it completes the shift. does the same thing when downshifting. it has the AOD transmission and is sitting on 33'x14.5in super swamper tires with i believe a 3 or 4 in lift(no sure on that). can anybody give me some pointers on what might be the problem. was told at sell that the tranny is fairly new.

thank you