5R55E 1st gear only -- long post

[iverger]

I hate to start a new thread for this but, I've search and read for 2 days now and I am not sure what the answer is so here I go.

The Truck: 98 Ranger 4x4 4.0L with 5R55E. 175K miles on truck, and transfer case but tranny and TC have about 30k miles since professional rebuild.

The Story: Found a little mud a few nights ago, and all to late I found out that my vacuum hubs were not working anymore, big surprise. Anyway, did a little rocking back and forth to try to free myself. After about 3 or 4, Reverse to Drive cycles, Reverse decided it wasn't going to play along anymore. No clunks or bangs just like I put it in neutral......great. Call a friend, get pulled out, and gingerly begin heading for home. Interestingly the only gear I had is 1st. Since I was only a few miles from home I headed home slowly and hit the forums.

The Symptoms:
1) No reverse
2) xfer case seems to shift fine from high to low range, obvious difference between 1st low and 1st high.
3) While in drive, the tranny "free wheels" when the throttle is released, but not in 1st manual.
4) When in drive, the tranny does not shift from 1st. have not tried anything higher than 4000 rpm.
5) 1st gear feels strong, no slipping.
6) O/D light was flashing on the way home from the mud.

* Don't have a pressure gage, I will hunt one down if you think it would help.
** Nearest place to get the codes pulled is 8 miles away over busy roads. I have to get it trailered to get there which I hope to get done next weekend.

I think this is a VB gasket issue but I'm hoping for some confirmation. Also, with just 30k miles on the rebuild should I still consider replacing the EPC?

Thanks for listening.
Bob

 

[BrooklynBay]

Maybe they didn't replace the EPC, or any other solenoids in the previous rebuild. You might have broken the rear one way sprag while rocking it back, and forth. It might have had a soft parts rebuild, so the hard parts are borderline from failure.

 

[Glacier991]

Your symptoms do not point to one single identifiable hydraulic circuit or mechanical component that I can tell. Usually when I hear of a "rocking" created malfunction I expect to find the front planetary race twisted off inside the front sprag.... but that doesn't fit here since you have manual 1st.

So I come back to where you are.... I'd pull the VB and see if you have a blown gasket anywhere. While obviously codes are nice and helpful, I think this might be an acceptable first step.

 

[iverger]

Thanks gents, could one of your humor this rookie and tell me what a sprag is/does? By reading other posts, it appears to imply that I need a complete rebuild, so I'll start with Glacier991's advice and pull the VB first.

Thanks,
Bob

 

[Glacier991]

If you look up "sprag" in a dictionary, it will tell you that it was like an extra spoke in a wagon wheel, that could be pulled out to prevent rotation at rest. I think a better example is the joke about why they give Viagra to old men in rest homes - to keep them from rolling out of bed.

A sprag is a ring of little .... hmm... trying to think of the word to describe... little levers with rounded ends... they lay kind of tilted in one direction, and when the thing they ride against is rotating in that same direction, they allow it, sliding on it. But when the thing tried to go "against the grain" they twist upright and grab, and hold it from rotating.

Does that make sense? Your typical sprag ring is between 20 to 30 of these, and they vary from maybe 1/2 inch wide to up to larger than that.

The front planetary in the A4LD/4R and 5R has a solid metal round piece that the sprag grabs. Unfortunately that piece in stock models is on a spline and can be twisted and ruin the splines so it just rotates, hence the sprag cannot hold. Newer mods weld that solid ring to the rest of the planetary greatly increasing it's resistance to this common problem. I use welded ones in my rebuilds.

 

[iverger]

Considering that I drove the truck home a little ways would the circulating oil have flushed "sprag bits", for lack of a better term, into the pan if that was indeed the problem?

I'll be making a new big red spot on the garage floor as soon as I get home tonight. I'll post back what I discover.

Thanks again.
Bob

 

[BrooklynBay]

The parts from the sprag would only come out if everything is broken. They are heavy, so I don't think they would go out of the pan after they are in there.

 

[BrooklynBay]

Check this link for some pictures of an exploded rear sprag from a neutral drop: http://www.explorerforum.com/forums/showpost.php?p=1395433&postcount=14

 

[Glacier991]

That pic looks more like an early A4LD when sprags were made with rollers and accordian springs....roller one way clutches is what they are called - quite different in the way they work than the kind I just described which are true "sprags". All sometimes are lumped under the name "overrunning" clutches. The newer versions of the A4/4R/5R are more as I described. Maybe I should do a thread on sprags and one way clutches.... geeze I have enough sitting around (none fragged though). And the 4R70W has something even different yet.... a "mechanical diode".

 

[Glacier991]

One more note. A Front sprag failure in the A4/4R/5R more often than not tears up the front planetary race. A rear sprag failure usually results in a total fragging of the rear planetary. You'll get metal, but it is usually not sprag parts in the case of the rear failure. You may not get anything or not much from a front failure.

 

[Bent Bolt]

You need to get the codes pulled first . That will get you in the right direction. I would suspect that the VB gasket has failed. Pull the valve body off and confirm that the VB gasket has failed-which it likely has.

 

[iverger]

Pulled the pan and found a good deal of filings and a few respectable size pieces. I put 2 picks on this Cardomain thingy.
http://www.cardomain.com/ride/2569375

One shows the largest pieces from the pan sitting on top of the filter, the second is trying to show the filings in the pan but its didn't come through well.

Didn't pull the VB out yet, not sure it is was worth the effort.

Any Thoughts?........I'm thinking about building a trebuchet.

 

[Glacier991]

Don't waste your time on the VB... something is disintegrating, and I am betting it is in the rear end of the tranny... It is rebuild time... sorry

 

[iverger]

Thanks, I figured as much.

One last question, if I am able to get my hands on a replacement, does it matter which year or whether the source is a Ranger or Explorer as long as its a 5R55E from a 4x4?

 

[Glacier991]

I'd get your year or newer. And while I am not entirely sure, I think the "5R55E 4x4 output shaft and extension housing" lengths were the same in all applications... I MIGHT BE MISTAKEN... but I don't think so.

 

[iverger]

I'd get your year or newer. And while I am not entirely sure, I think the "5R55E 4x4 output shaft and extension housing" lengths were the same in all applications... I MIGHT BE MISTAKEN... but I don't think so.

I have a line on one from a 99 Ranger with 17k Miles.....and a 30 day warranty. But according a salvage yard cross-reference manual and www dot car-parts dot com, which I believe uses the same cross-reference source, the 99-00 is not interchangeable with a 98.

Of course neither can tell me any more than that. If I pull mine and do a visual compare, what should I be looking for? I'm not sure when Ranger got the SOHC implant, maybe its just bell housing and/or sensors.

Thanks again for all your help, its been an educational week.
Bob

 

[Glacier991]

I'm not much help. The things you will be looking at are a. overall length from output shaft end to front bellhousing. b. input shaft length ( this is easily adjusted by using your old input shaft) c. bellhousing front end to extension shaft housing rear end (I am unaware that this is any different in ANY year to year comparison). d. Output shaft splines count/size... I am unaware and ignorant if there was any change.

Sometimes newer models had sensors older models did not... left unplugged hurts nothing since your old PCM isn't looking for those inputs.... in fact as I cogitate on this, I bet that is it.... I think they added another shaft speed sensor in 98.

I'd go for it.

 

[greasemanicure]

When I replaced the 96 4R55 with a 97 5R55 recently on a 96 Ex 4X4, the extension housing and output shaft lengths proved to be the same. More differences at the front end of the tranny as the bell housing area around the starter are different as shown in the Frankentranny thread. I enjoyed my adventure and hope that you do yours, and have as happy an ending.

 

[greasemanicure]

I know from 96 to 97 they added an input sensor and an output sensor. Glacier is right that left unplugged, your PCM won't know the difference. Watch out for subtle differences in the range sensor switch. I had to swap my original to the new tranny as the donor came from one with an electronic instrument cluster and had a different pin out.

 

[iverger]

Thanks to all.

It turned out to be a straight bolt in job. To backup Glacier991's advice I spoke with a local Ford tranny tech that came highly recommended. He was confident that the electronics were the same. His thought was that the "Machine Codes" didn't match from 98 to 99-00 because of some internal tuning differences and hence the lack of cross-ref at the salvage yard.

Anyway, only had time to put on 10 miles today but everything feels great, ran through all the gears, no codes, smooth up and down shifting. I noticed one interesting difference though, the fill lines on the dipsticks are different. The 99's fill line is 9/16's higher. My first thought was to compare pan depths, but they measured the same. It occurs to me now that the new fill tube may be shorter for some reason and the stick sits deeper in the pan, but that doesn't seem likely. Maybe Ford just decided that an extra 2/3's or so of a quart was a good thing.

There are a few pics of the dip sticks here:
http://www.cardomain.com/ride/2569375/1

greasemanicure, the input sensor added in 97 disappeared again in 98 and on. According to the same Ford tech it was really only there in spirit in 97, never used by the PCM.

Thanks again to all, its been an educational adventure.
Bob
P.S. Anybody want a chunky 5R55E core, just come get it?