5r55e to 4r55e... can it be done and if so, should it?

[salsa3651]

I'm trying to find information on swapping a 5r55e to a 4r55e but I haven't been very successful. I see alot of information on 4r55e to 5r55e though. And before anybody starts asking me hard questions... its not for my Mountaineer. My question is for Elessar65's 98 Explorer

Thanks guys!!

 

[PopRichie77]

Big question, WHY? You would need all wiring, and computer but the problem that I see is the engines are different and the older computer, needed for the 4R55E, wouldn't run the 98 SOHC engine and the wiring wouldn't match up. I could be wrong but I would say, no.

 

[Elessar65]

Thats about what I figured. And as to why, because my truck is 300 miles from home with tranny problems ( no 3rd gear). There is a transmission from a 95 that gmanpaint has sitting around from his manual swap.

 

[PopRichie77]

If it still drives and there is no funny noises, no 3rd gear shouldn't stop you from driving home. However it may go into limp mode which starts in 3rd when in drive, manual 2nd is actually 3rd gear. So you might only have manual 1st. if it will get over 30mph in manual 1st, then shift to drive, it should shift to 4th and so on, You may have already tried this, that is if it moves and it's to far for 1st gear. I see your problem.

 

[Elessar65]

If it still drives and there is no funny noises, no 3rd gear shouldn't stop you from driving home. However it may go into limp mode which starts in 3rd when in drive, manual 2nd is actually 3rd gear. So you might only have manual 1st. if it will get over 30mph in manual 1st, then shift to drive, it should shift to 4th and so on, You may have already tried this, that is if it moves and it's to far for 1st gear. I see your problem.

Hmm, I don't think I tried that. 1st and 2nd on the selector work fine, I can feel it shift to 2nd, then when it shifts to 3rd there's nothing there, neutral. it will stay in the false neutral until speed slows and it downshifts, or I manually downshift into 2. If it will make it home I'll be happy, I have access to a shop and lifts at work (if its a slow day and I'm not tieing them up and preventing paying customers for getting service). and as long as i can drive it through town a few miles to work and home I'll be happy til i get it sorted out. I just want to get it home.

 

[PopRichie77]

If you have manual 2nd, which is actually 3rd gear then 4th gear is missing. Do you have reverse, I am looking at the apply chart trying to figure out what is not working, may be a valve body issue.

 

[2000StreetRod]

same number of gears

It's my understanding that the 4R55E and the 5R55E have the same number of actual gears. The "2nd gear" in the 5R55E is achieved by engaging 1st gear and overdrive. I agree with PopRichie77 that you should be able to drive home without 3rd. Just manually select "2nd" and accelerate until the engine rpm is above the normal shift point. Then let off the accelerator and shift to drive. The transmission should skip "3rd" and go to "4th". Then step back on the accelerator.

 

[PopRichie77]

Most people think that manual 2nd is 2nd gear it is not, in the 5R55E it is 3rd gear, ford didn't change the selector and left the 2 on it. This can be found in any rebuild manual or apply chart.

 

[Elessar65]

I have manual 1st and 2nd. And I am pretty sure I have reverse, not certain though. Its been a month since I have messed with it.

 

[Elessar65]

That's good news if I can get it home under its own power. I will give it a shot tomorrow morning when I get to where its at

 

[PopRichie77]

Ok, after rethinking this, it's probably 2nd gear that is missing, which is the same valve as 4-5 so it might not shift to 4th gear, if a valve body issue, if not you lost the OD band and it will shift to 4th. You should still be able to drive in manual 2nd (3rd) gear and get 50 mph, just watch the temp.and stop every 50 miles or so to let the trans cool.I would try it, don't use drive to start out or it will go into limp mode.

 

[2000StreetRod]

Please clarify

Most people think that manual 2nd is 2nd gear it is not, in the 5R55E it is 3rd gear, ford didn't change the selector and left the 2 on it. This can be found in any rebuild manual or apply chart.

OK, now I'm confused. I believe the published ratios for the 5R55E are:

1st 2.47:1
2nd 1.86:1 (2.47 x 0.75)
3rd 1.47:1
4th 1.00:1
5th 0.75:1

Are you saying that when "2" is selected on the gear selector that the ratio is 1.47:1? That would explain why my data log of engine speed vs vehicle speed was off when driving in "2". I thought the selected ratio was 1.86:1.

 

[PopRichie77]

That's correct, manual 2 is 3rd 1.47:1
View attachment 60490

 

[Elessar65]

Ok, after rethinking this, it's probably 2nd gear that is missing, which is the same valve as 4-5 so it might not shift to 4th gear, if a valve body issue, if not you lost the OD band and it will shift to 4th. You should still be able to drive in manual 2nd (3rd) gear and get 50 mph, just watch the temp.and stop every 50 miles or so to let the trans cool.I would try it, don't use drive to start out or it will go into limp mode.

Well that's. A little disapointing. But I still think I can get it home that way. Even if it goes into limp mode, I can clear that by disconnecting the batt with the lights on for like 10 min or so.

 

[PopRichie77]

On a 98 you should only have to turn the key off and restart to reset it out of limp mode. Start in manual 2 then at 45 put it into drive if it shifts to 4th, it should also shift to 5th (OD) converter will lock up under light throttle in manual 2 (3rd gear) also. Try it, that's all I can say if there is noises then you shouldn't drive. A broken OD band shouldn't give a problem, if that"s what it is.

 

[2000StreetRod]

explains WOT test

That's correct, manual 2 is 3rd 1.47:1

Thanks! That explains why when performing my WOT tests in "2" for my custom tune I was going 94 mph at 6,000 rpm instead of 74 mph. It also explains why my Sport was so slow to accelerate from a standing start. Now I know that when the engine is lugging in 4th I can shift to "2" to downshift only 1 gear ratio.

 

[PopRichie77]

You got it

 

[Elessar65]

Well, when I got to the truck this morning I tried going in manual 2 up to about 45mph and shifting into D, no dice. So I went ahead and got a tow dolly from Uhaul and got 'er home that way. Towed it with the gf's 02 Mounty, and it did surprisingly well for a V6. The braking sucked, but i thought it would be a lot worse. Anyways, the truck is home now, I can drive to work and back through town in 2 until I get it fixed. Thanks for all the help guys, especially Steve.

 

[PopRichie77]

Glad to here you got it home. Does it have reverse? You can check for a broken band by adjusting it in to 10 lbs/ft if it wont reach that, it is broken.

 

[Elessar65]

Yeah, reverse works just fine. I need to do some research, try and figure some stuff out before i get into dropping the pan and VB and just poking around in there.