missing gears

[art]

first of all i would like to say hi to my fellow members, while driving my '99' 4.0 ltre auto i noticed the amber warning light on with the message GEARBOX FAULT and wouldn't go into top gear so after my trusty aa patrol man kindly piggybacked my car home thought i'd check the oil level, oops no dipstick after finding out you dip it through the drain plug (sounds odd) not had chance to look yet also found on web about a spring in the box that may need replacing when lost top two gears,anybody could help on how to find literature and diagrams on auto boxes,or has had this fault and fixed it? cheers

[Neil]

Yes, you have FORD 5R55N transmission - welcome to the club. I have been having years of problems with it, many folks experience no problems, however, some have changed transmission every 20k miles

I suggest reading error codes to see what error code you can pull from the ECU. I guess it's a pre-stroke spring, and I hope I am correct as this is an easy and CHEAP fix. Doesn't require pulling off transmission, you just need to remove oil pan and access it from there. A new filter and Mercon V should be installed at correct level.

New spring ~ <20$, filter <20$, oil depends, mostly 7$ per liter

Does the error (amber light) go away after you switch the engine off? Does the error return, when you accelerate at 40-50 miles per hour, with strange switching between the gears, then switching back to lower gear (like 3rd gear)?

[art]

thanks for your quick reply ,sorry for the delay in responding ,  answer is yes to everything that you said it does, How big a job is it to change this spring and where is it to be found?

[mobrien]

right around 40 - 45 mph my 2000 S goes into 4th, then reverts back to third (I accelerate very little and consistently, drives other drivers nuts). Once I accelerate over 45 is goes back to 4th and no issues from that point. Could this be a similar issue? Or maybe nothing? It is very consistent and no other unusual things noticed.

[Neil]

thanks for your quick reply ,sorry for the delay in responding ,  answer is yes to everything that you said it does, How big a job is it to change this spring and where is it to be found?

Probably should take 2-2.5 hours with tranny oil refill, not much more. The spring can be accessed by removing the oil pan of the tranny.

[Neil]

right around 40 - 45 mph my 2000 S goes into 4th, then reverts back to third (I accelerate very little and consistently, drives other drivers nuts). Once I accelerate over 45 is goes back to 4th and no issues from that point. Could this be a similar issue? Or maybe nothing? It is very consistent and no other unusual things noticed.

It could be:

-incorrect fluid level
-solenoid problem
-4-3 pre-stroke spring

[GoCubsGo]

Hey Guys,

Sadly, I too have a 5r55n transmission.  The dealership wants $4300.  The codes that came back were PO734, 735, and solenoid c.  I've read that it is due to the 4-3 pre-stroke valve spring.  I bought the spring and was curious to see if anyone had any advice on how to change it.  Can I access it just by dropping the pan, or do I need to take down the valve body?  I have talked to a guy at sonnax and he said that a ridge can build up where the spring was grinding into the metal and I need a tool to remove the build up.  If that's the case, isn't it easier to buy a remanufactured valve body.  And finally,  I've also heard that this is not due to the 4-3 spring but is actually due to wear in the servo-pin bore.  Which is in the housing and not the valve body.  I tried changing the fluid and filter so far, hoping that I might get lucky...not so much.  And as much fun as it is getting under the car, I don't want to have to do this like 5 times trying to figure out which problem I actually have to fix.  I don't know really were to start and would apprieciate any advice/help. Thanks.

[fhwq13]

Try this one:  http://sonnax.com/instructions/56947J-S1-IN.pdf and: http://www.sonnax.com/announcements/56947J-S2.pdf

This should help you, Sonnax also have the parts.

Cheers from Oxford

[Neil]

Don't waste your time visiting dealer - order the spring and have a mechanic replacing it. Rather easy and quick. fhwq13 already sent you the info and detailed photos where it is located. You can access it just removing the tranny pan....