4.0 swap questions

[90b2louisiana]

does anyone have a link to a post where i could get some info on 2.9 to 4.0 swap parts needed and procedures?

[kieth]

i dont know of any links but i do know that it is a bolt in swap and you can use your same motor mounts and wiring harness.
i did a 2.8 to 4.0 swap and it was a little different. not as easy as it will be for you.
also your fuel lines should hook right up.

[04sd]

You can't use the 2.9 harness on a 4.0, you need the harness that came with the donor engine.
Besides the engine you'll need the computer, bigger radiator from a 4.0 as well as a trans from a 4.0. The 4.0 will bolt up to the 2.9 trans and work but isn't made to handle the power. Your best bet is to try to get a complete donor vehicle, the cheapest/best being a '91-'92 Explorer. Then get the wiring diagrams for your truck and the donor truck, compare the two and change the few wires that are different. I did a '91 Ex into my '90 BII a few years ago and it was only two wires to be changed on the big round harness plug at the fire wall. From the firewall forward I used the harness from the Ex. The closer you can get to the same year as your BII the easier the wiring will be. If you could find a '90 Ranger with the 4.0 it might be a plug in swap. Also, if you get a complete vehicle for parts you can swap in the d35 and 8.8 axles.

[kieth]

Actually, you can still use the wiring harness from the 2.9 you just have to change it up. I have seen it done, so I know it works. But thanks anyways.

[tekatlarge]

An A4LD automatic is the same transmission whether it be behind a 2.9 or 4.0. Same power capacity no different.

[Ranger Dave]

An A4LD automatic is the same transmission whether it be behind a 2.9 or 4.0. Same power capacity no different.

is that right

[tekatlarge]

I knew you would bite on that one Dave!

I should have clarified that. There is a small HP capacity increase in the newer Exploder trans. This is due mainly in part to process evolution and failure analysis of the earlier transmissions. They noted some weak areas and made some improvements in the center support and other things like drums and other components.

Now I wasn't saying what I said to argue which transmission could take the more power. I was simply showing people there is no secret Heavy Duty bolt in trans when it comes to a A4LD. Some people get the misguided information that if it was behind a larger engine it was automatically superior in power capacity. That is not automatically true. If I were asked what transmission I am using I would reply a 92 Exploder trans and I chose that trans for 2 main reasons. The newer case transmissions can be improved more than the older ones with out a lot of cost. The second main reason is that I got the 92 Exploder trans for nothing. Simple economics.

There I have said my 2 cents worth. Have fun.

[Ranger Dave]

what about clutch packs?? is there the same amount clutches in a 2.9 tranny as in the 4.0 one??

[Ranger Dave]

Same power capacity no different.

Even More A4LD Information

The A4LD 4-speed, overdrive transmission has been used in the Ranger/Bronco II/Explorer platform since 1986. As most of the early overdrive auto trannies, the A4LD was not real reliable in the early years. The first major change came with the introduction of the 4.0 in 1990. While still an A4LD, the 4.0 version was significantly stronger than the non 4.0 versions . It also had a computer controlled torque converter lock-up. In 93.5 another major upgrade of this transmission occurred. In addition to the computer controlled lock-up, the transmission also got a computer controlled overdrive engagement. Internally, most of the thrust washers were replaced with torrington bearings, which made the tranny much stronger.

While the A4LD has gotten a bad rap, it is actually a good strong transmission. The newest version is still an A4LD, it just goes by another name due to the fact that it is completely computer controlled, and has a 5th gear.

There are modifications and upgrades available to this tranny. Better grade clutches and bands, better converters with improved lock-up clutches and brazed fins (stock converters were known for clutch failures, which takes out the entire trans), welded planetary cages, shift kits, and the ability to upgrade a non 4.0 tranny to 4.0 specs makes this tranny very versatile. At its strongest (off-road race application), these transmissions are holding up to V6's making in excess of 300hp. Once the engines get much higher than that (depends on usage) the main shafts will start bending.

One of the most interesting upgrades available for this transmission is the off-road race package. This includes numerous valve body and internal modifications. These modifications are easily attainable from a good tranny man. What this modification does for you, is give you an automatic with all of the advantages of a manual....... and none of the downfalls. Run in drive, you can split the 3 gears with overdrive, and you can lock-up the converter in any of the gears. This gives a much greater availability of ratios, and makes it real easy to keep the engine in its power curve. Also, because you can lock-up the converter whenever you wish, it also helps to keep the transmission cool. This mod also allows the transmission to be used completely manually.

When having an A4LD rebuilt, there are a couple of things that you need to make sure of. First and foremost, do not let a shop do a soft parts fix only (clutches, servos, and bands). This will almost ensure that you will have another repair needed right after the 1-year warranty is out. Other things you want to have replaced are: forward one-way clutch (always), overdrive drum (stamped tin, replace if out of round or heat damaged), pump (Ford only, rebuilds are prone to failure), and the converter (get the better converter with the improved lock-up clutch and brazed fins). Also, get references from the shop and call the people. Just because they can rebuild TH350's and C4's does not mean they know what they are doing with overdrive trannies.

[tekatlarge]

Thanks Dave. I figured if I just put something out you would come back with a detailed explanation and save me from so much typing!

[04sd]

An A4LD automatic is the same transmission whether it be behind a 2.9 or 4.0. Same power capacity no different.

So your statement here is just total garbage. I don't see any part of it that's correct. Not to get on your case but without someone like Dave to correct you, a newbie goes off thinking he can bolt the 4.0 up to his 2.9 trans and he'll be good to go. Why contradict the information that was given if you don't have clue? Just trying to get your post count up