4r44e-->5r55e swap done, questions popping up! HELP!

[redrobster]

Hello Gentlemen!

I am in need of some information/advise. I bought a 95 4.0 ranger 4x4 a couple months back, everything was solid except the transmission (big surprise i know). SO last weekend my brother and I swapped out the transmission for a different one.

When i bought the truck it had a 4r44e in it, I found a replacement 5r55e that would bolt right up. Both my brother and I researched the compatibility of the swap and everything looked good. fast forward a couple days, the swap is done and trans seems to have a dual personality. sometimes it will slip as it goes from 2-->3 and then when i'm going about 50mph it will jump back and forth from what i assume is 4th-->OD, making it SUPER annoying! But then i will get a couple days where the shifts are solid all the way through each gear, but there is no OD. The shifts are harder, but not something i'm not willing to live with. The Flashing OD light on the dash has come and gone here and there. I honestly look forward to seeing it, because i know i will be getting the non-slipping, no OD personality from the trans.

I would prefer to have the no OD and non-slipping trans rather than the slip and slide one i drove to work.

What are your thoughts?

 

[Dweano]

I did the same and am having some of the same issues. No flashing OD light tho. Only thing I can help with is saying that the 5r55e in a 4r55e original vehicle will still only have 4 gears

 

[redrobster]

I think I need to swap out the transmission control computer. Both the transmissions are computer controlled. I would love for a guru to pipe in and confirm or deny my thoughts lol. Also some direction on where to find said computer would be awesome!!

Any other thoughts?

 

[Robman]

I'm thinking perhaps you DO need a newer computer to go with the 5 speed auto... I look forward to seeing what others have to say.




- Once place to find a computer is the scrap yard.

 

[JK080]

The 4R55E and the 5R55E transmission is pretty much the same transmission, the 5R55E does not have any extra parts to give it its 5 gears. The computer turns the overdrive section on between 1st and 2nd, so how it works is

4R55E
1st gear - 2.47 ratio - forward drum
2nd gear -1.47 ratio - forward drum and intermediate band
3rd gear - 1.00 ratio - forward drum and direct drum
4th gear - 0.75 ratio - forward drum and direct drum and overdrive band

5R55E
1st gear - 2.47 ratio - forward drum
2nd gear - 1.87 ratio - forward drum and overdrive band (basically a over driven 1st gear)
3rd gear - 1.47 ratio - forward drum and intermediate band (basically 2nd gear)
4th gear - 1.00 ratio - forward drum and direct drum (basically 3rd gear)
5th gear - 0.75 ratio - forward drum and direct drum and overdrive band (basically 4th gear)


The end result for both transmissions are the same, there is no benefit to have the 5R55E in place of the 4R55E in my opinion, it only opens the door to have interchangeably issues. I am not sure that swapping the computers is the answer, it may give you the extra shift but it may cause other issues with the other things the computer controls. There is a difference between the 5R55E and 4R55E valve body separator plates, if they are installed in the wrong application it will give you trouble codes, I cant remember what they are because I just don't do the swap.

If you had control of the way the computer works you could in fact turn the overdrive section on between 2nd and 3rd too and end up with a 6 speed.

The biggest benefit from this kind of swap would be from the 4R44E to the 4R55E, the 44 and the 55 are duty ratings. They do this for the different engines, the 55 will be found behind the V6 and the 44 is behind the others. The 44 stands for 440 foot pounds of torque and the 55 stands for 550 foot pounds of torque. The 44 models will have one less clutch in the drums and some other light duty differences.