2005 Mounty 4.0 2wd automatic - no reverse

[bronchole]

2005 2WD 4.0 V6 5 speed automatic Mountaineer with 125K miles

My wife's rig started having problems with reverse a couple weeks ago. She mentioned it but I didn't really pay much attention to it.

The other day I went to use her Mounty to back a small trailer up our driveway and found that her Reverse gear was barely there. Took it out for a test drive. All forward gears seem to work just fine. Torque converter locks up fine. Just a weak to non-existent reverse. It doesn't seem to be any different cold or warmed up.

I am going to take it to the trans shop tomorrow and see what they have to say. After doing a bunch of research here I am guessing that it is either something related to the reverse servo or something worse.

Any ideas here?

I am not against doing some work without pulling the trans. But if it a full tear down and rebuild I'll probably have a shop do it. I already have enough projects around the shop. I don't need another one.

 

[bronchole]

Bummer, no replies yet.

More information:
I took it to a local transmission shop and had them look at it:
- Fluid looks OK and is up to the correct level
- All electrical connections seem to be OK
- All linkage/cables and vacuum hoses seem OK
- Road test OK other than no/weak reverse
- Computer scan, no codes in system

I paid to have them run a solenoid and pressure check:
- Solenoids are operating as outlined by manufacturer
- Line pressure is at 140PSI or lower at idle
- Line pressure is at 200 and below at stall in reverse only
- all other pressures are within manufacturers specs

They noted that they suspect internal damage and they recommend tear down for inspection to determine the extent of the internal damage.

The current estimate is $1100 to remove and diagnose the transmission. Ruff estimate of the total when done is high $2000 to low $3000 by the time I can drive it away.

Anyone have any insight if this is something I should look in to further or should I just bite it and get it done?

 

[bronchole]

I need to figure out exactly what transmission this is so I can start shopping for rebuilt units off the shelf.

 

[imp]

I need to figure out exactly what transmission this is so I can start shopping for rebuilt units off the shelf.

5R55S transmission. I'll be back after consulting manual. imp

 

[JK080]

You could have either a 5R55E or a 5R55S transmission, the 5R55E has a dipstick, the 5R55S does not.

I would have to agree that the problem with reverse in your case appears to be a internal issue that would require rebuilding the transmission and the quote you got is reasonable with a warranty. The high end price would be expected if major components like the gear train or pump and valve body have to be replaced. Your issue most likely would be with the rear band and just mileage wear so hopefully they can work with you to keep the cost down.

Rebuilding the 5R55S you would want them to replace all three bands and servo pistons, sleeve the servo bores, basic overhaul with a kit with frictions, update the pump valve, replace the input sprag and converter at a minimum. The 5R55E would be the same except for the pump valve and sleeving the case.

I would let a shop handle this for you so they can help you if things go wrong, if you buy a transmission off a shelf you will have to pay someone to install it and if things go wrong you will have to pay them to do it again.

 

[imp]

@bronchole
As I see it, only one major component is involved in Reverse, when in "D" with O/D OFF switch in either ON or OFF position:
Low/Reverse Band. Now, that band is also applied in Manual "2" and "1" positions. You did not mention trying 3, 2, or 1. If 2 and 1 are affected, slip, or no go, good bet L/R band is shot: broken (which would give NO reverse, is some effort at movement in Reverse seems present, band may be cracked, badly worn, OR the Reverse Servo is malfunctioning.

The Reverse Servo is nothing more than a cylinder containing a piston driven by hydraulic pressure. Movement of the piston "applies" the Reverse Band tightly around the Reverse Brake Drum, preventing it from turning. Failure to prevent it's rotation results in no Reverse, and affects "2" and "1".

The L/R Servo (don't let these steamy catch-names throw you, it's nothing more than a simple piston device) is attached under the Control Valve Body, and is accessible by removal of the oil pan. This can easily be accomplished with the transmission in the vehicle. If, upon teardown of the Servo, it's demise is evident, the transmission need not be disassembled. If Servo is OK, access to the band is by disassembly of the ENTIRE transmission, as it's the last component accessible, removed through the FRONT of the transmission.

If it were me, and the Servo was OK, I would opt for a Ford Authorized Remanufactured Transmission rather than rebuilding your old one. Just my opinion. imp

 

[imp]

@JK080
Sorry, I was typing as you were posting, not trying to "be first", as you are the guy with the transmission "smarts". I was not aware that the "E" was used at all in the 3rd. Gen, especially not 2005. Anyhow, only "S" was used in 2004, my year.

My reason for preferring a rebuilt trans. is that many shops will re-use critical parts, especially thrust bearings and washers. imp

 

[JK080]

@JK080
Sorry, I was typing as you were posting, not trying to "be first", as you are the guy with the transmission "smarts". I was not aware that the "E" was used at all in the 3rd. Gen, especially not 2005. Anyhow, only "S" was used in 2004, my year.

My reason for preferring a rebuilt trans. is that many shops will re-use critical parts, especially thrust bearings and washers. imp

No worries I wouldn't expect the 5R55E either but my little handy dandy transmission ID chart listed it so I mentioned it.
lol

 

[bronchole]

Thanks to the both of you for replying.

I just took it for a test drive. When in manual 1, 2 or 3 it pulls without significant slipping. It acts exactly how I would expect a perfectly functioning unit to work. At this point reverse is completely not working.

A little more history on the reverse problem. 3-4 weeks (700-1400 miles ago) the wife tells me that the trans was slipping in reverse when she tried to back up a steep driveway. She tells me that it was progressively getting worse over the next 2 or so weeks until I tried to use it the other day. When I started trying to use reverse it defiantly pulled a bit in reverse, but not strong and was defiantly slipping. Now I would judge reverse as totally non-operational.

No dip stick so I am taking your word for it being a 5R55S.

 

[bronchole]

So reading thru the info above, I am thinking of trying the replacement/upgrade reverse servo. Any suggestions on what kit to buy for that? What am I looking for as far as damage to the reverse servo when I take it out... Other than obvious scoring and such.

I am also going to look in to options for purchasing a rebuilt transmission. I have access to a lift and all the knowledge and experience necessary to R&R the trans. Just not the time to have it down and apart while I stumble thru rebuilding the trans.

I have somewhat successfully rebuilt a 4R70W before.

 

[JK080]

I rarely see problems with that servo in the 5R55S what I do see is worn out or broken bands, you could look at it just to make sure but if all looks good I would be prepared to remove the transmission at that point.

Here is a band that the friction material has worn off, this is very common.

 

[bronchole]

Ya, researching this it looks like the reverse servo is sealed with an o-ring already. Only real possibility is if the o-ring has worn out. Guess I will start looking in to re-manufactured transmissions and see what options there are.

Thanks for your help.

 

[bronchole]

Looks like re-manufactured units are pretty available in the $1700 to $2000 range.