4r55e to 5r55e | Ford Explorer Forums - Serious Explorations

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4r55e to 5r55e

goldenrod81

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Joined
March 18, 2006
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City, State
berwick, Pa
Year, Model & Trim Level
96 xlt
To start I have a 96 4.0l xlt with control trac 4wd. The tranny is shot. Burnt fluid, hard shifting, lag between shifts, od light flashing. I guess I made the mistake of towing in overdrive. After searching about a dozen local junk yards for a 4r55e I have come up with nothing but 5r55e's and a4ld's. After reading some of brains frankintranny post I still have some questions before entering this project. Well alot of questions I guess. Bottom line for me is what all do I need to swap a 5r tranny over from the doner vehicle to my 96? ie: computer, shift linkage, torque converter, transfer case.... Also will the 5r guts have to be swapped into the 4r case? thanks for any replies.
 



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Welcome to Explorer forum.

Let's start by talking about the differences between the 4R55 and the 5R55. Main difference ? The extra gear (4 speed vs. 5 speed). The 5R achieves this by overdriving first gear. This little piece of magic is about computer control.

The guts are, well, interchangeable. At this moment I am not aware of any differences in the internals, but I might be wrong, but I am almost certain that should there be a difference it would be backwards compatible.

It would be best to probably use your old case and valve body, and just swap the 5R55 guts into it. Since you will be doing that, it is a good chance to rebuild the transmission.

While you may not HAVE to, I'd plan on at least new sprags, bands (reverse band from the donor may be ok) and maybe find a welded front planetary. I'm also kinda big on replacing the rear case race on a rebuild. I'd also rebuild my VB.

I'm not sure if the 4R used the ZC cover on the OD servo, but I'd upgrade to that if it did not. Then your front servo would be ZC and the intermediate AB.

Let me know if I can give you any further help.
 






thanks for the reply glacier. Why would it be best to put the 5r guts into the 4r case? Do the cases connect differently to there components or mounts?
I guess I should state that im kinda just looking for the easy way out instead of maybe the best way out of my transmission woes. I dont want to hack it together or anything but I also dont want to get to well invested (time, $) in this project if you know what I mean.
 






At the risk of pretending to know something I do not, what your question boils down to is:

"If I put a 5R55E transmission in an Explorer that HAD a 4R55E in it, will the 5R55E act like, and respond to the computer as if it was a 4R55?"

I am guessing not. But I do not have first hand experience. I was confident if you used the VB and case this wuld not be a problem, was all. I wish I was more help. I only know what I know.... and won't shine anyone on about what I do not.
 






Let me put this in a different light. My fantasy solution to this problem would be to remove these parts from my 96: 4R tranny, computer, and torque converter. Those parts would be disregarded. Then replace them with the 5R tranny, the 5R computer ment to run that tranny, and a 5R torque converter.
In my fantasy solution I am most blindly hoping that the 5R transmission and torque converter will bolt right to my vehicle, and that the newer 5R computer will still run my engine and perform the other functions it has in my 96. thanks again
 






Make sure to get a computer from an OHV. If you're pulling a 5R there's a chance its an OHC.
 






One of my concerns about your fantasy solution is that the number of sensor inputs goes up, year by year. Since your Explorer won't have some of those sensors that the newer donor vehicle had, you will either have to live with a CEL, or find a way to defeat it... depending - this can cause issues at SMOG check time. In short, I'm not thinkin' it will be that easy. 410Fortune has some experience with this as do several other board members. You might post this question in the computers sub forum of the "Under the Hood and Driveline" forum.
 






My question is if you are going to take the time to gut the 5r and try to transfer them to the 4r why wouldnt you just go ahead and rebuild the 4r you can use just about all the hard parts from the 5r and then get you a rebuild kit and a new torque conv. to me this would be the cheapest solution. Just my thinking though i rebuilt my 4r for about 350.00 parts and my own labor.
 






Thanks for the good info fellas. Im new to the explorer world and really have no idea when it comes to how things evolved over the years with these vehicles. Thats why I just threw my idea out there. I've done this limited sort of hybridizing before with other cars and was hoping I could get away with it now.... I guess not though.It appears in 97 they changed from pushrod to ohc motors so that alone kills my not so simple plan. Ive never opened up a tranny before so that intimedates me some but maybe I'll give it a shot.
 






Toy borrowed tools.... and so can you. With the right tools it is VERY doable.
 






goldenrod81 said:
Thanks for the good info fellas. Im new to the explorer world and really have no idea when it comes to how things evolved over the years with these vehicles. Thats why I just threw my idea out there. I've done this limited sort of hybridizing before with other cars and was hoping I could get away with it now.... I guess not though. Tod and Glacier are right. In 97 they changed from pushrod to ohc motors so that alone kills my not so simple plan. Ive never opened up a tranny before so that intimedates me some but maybe I'll give it a shot.

They still produced the pushrod motor for quite a few years, my 98 has the pushrod motor and 5R55E tranny.

Dan
 






yea as far as i know the SOHC didnt come out till late 97, and im sure it didnt just replace the OHV right away. Maybe it was a dealer option?
 






my mistake. Should have read my resource more carfully. Im about ready to just explode the explorer.
 






Goldenrod,

The 4r55e is similar to the 5r55e, but there are differences, including the digital range selector, an added turbine speed sensor, and upgraded thrust bearings etc. The 4r55e won't replace a 5r55e, and I suspect that the 5r55e isn't readily backward compatible. I'm betting you'll also find wiring harness differences.

I'm aware of valving and clutch pack differences between the 5r55s for the OHV and the SOHC, but I believe those differences are minor compared the the 4r55e and the 5r55e.

The path of least resistance is probably a good rebuild of the transmission you have now.

Hope this helps
 






Thanks for that post Popeye! I had forgotten that the 5R55 added that rear case speed sensor.

Do you know what valving changed the various iterations took? I am curious if it was mainly sep plate changes or carried fully into the VB as well. Can you comment ?

By the way nice to have you on the site !
 






Hi Glacier,

Sorry to take so long to get back to you on this, but I don't have all the answers yet. What I do know is from the separator plate details is that there are at least three different 4.0L plates and the differences are basically different hole diameters at hole #100 and #170. The OHV motors get different separator plates for Ranger and Explorer and the SOHC motor has a unique plate as well.

I suspect these differences are fine tuning for "shift quality" to match engines with vehicle weights.

I'll try to check the valve body part numbers to see if they're listed as the same for the different engines.
 






I know <or maybe just suspect> the following: The VB castings are the same. If there is a difference in bore reamings I am not so sure, though I doubt it. I suspect the differences are in the springs (if any) and the sep plate hole borings. Be curious to see what we come up with. Appreciate your attention.
 












So the swap is possible or not??
The swap is not logically possible. I'm sure Glacier could jerryrig something to work, but it would be more time and money then the Ex is even worth.

Been there, done that, I know. You'd be better off having your 4r55e rebuilt. Had mine rebuilt for only 400 bucks. I removed and replaced myself, but 400 is still dirt cheap. Look around, you might get lucky.
 



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Swapping

ANY kind of swap, engine, trans, axle, steering, etc., is POSSIBLE, given adequate hard-headed diligence and stick-to-it-iveness. Practical? Another matter entirely.

Example: I hacksawed, by hand, a 13-inch diameter disc of steel from a large plate, bolted it to the front torus cover of a Hydramatic transmission, and hand-built a clutch assembly to use behind a 1949 Lincoln flathead V-8, installed in a 1952 Ford sedan.

Was this possible? Sure, but would I ever do it again? Christ, no! I was 16 years old, no money, but lots of ideas! imp
 






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