Check servo bore wear

[david56780]

Hello all,

I am going to be doing some work on my 2003 Explorer's transmission (change pan oil, filter ect) and I thought it might be a good idea to check the wear on the servo bore while I'm under there.

I have a 5R55s, if that matters

How hard is it to get the pins out and inspect the bore? Would I be able to feel the wear with my finger or would I need to look at it?
Also if anyone could provide a step-by-step guide to getting the pins out, that would be much appreciated. I know some of the steps like taking off part of the exhaust, but I cant find an actual guide.

Thanks!!

Dave

 

[JK080]

I use a old servo pin to check for wear, the pin will move around in the bore if its worn.

I doubt you will have a old servo laying around to cut the pin out of it to use it as a tool, and I really don't think that you will benefit much from checking this in the first place.

If the servo bores are worn out and need to be sleeved the entire transmission will have to come out and be completely disassembled to sleeve the case, so you might as well just rebuild it.

I would not bother with checking the bores, just service it like you want and drive it until it starts exhibiting issues at will require a rebuild. There is nothing you can do to stop the wear.

There is a chance that if the servos are removed the band struts that index the bands may fall off or might not index the pins when you reinstall the servos. If this happens you will be missing gears and will have to remove the transmission to fix.

 

[exploreinstile]

Does frequent service intervals of these transmissions help slow down the servo bore wear? I'm just wondering?

 

[JK080]

There is nothing you can do to slow down the wear in the servo bores and I also will go as far to say that servicing the transmission will not prevent 90% of the transmission failures that come into my shop.

Its a constant battle with worn out valve body's and cases and broken parts that even changing the fluid once a day wouldn't prevent. This is one of those things that will happen around 100k so expect it, I have got to the point of not really checking them anymore other than conforming a failure, I sleeve everyone of them. Who knows I will probably see the ones I have sleeved back in a few years and the sleeves will be worn out.

 

[david56780]

Fair enough. Im well aware theres nothing that can be done to slow down or prevent the wear.

I just figured I might as well see how bad it is at ~94k

I dont really have any symptoms, just a slight 'buck' between 2-3. It feels like a slower gear change like in a manual when someone changes gear. So I was just curious to see what things look like in there.

Thanks for the info anyway!

 

[exploreinstile]

That's what I thought, thanks for the reply.

 

[BrooklynBay]

Get the servos with O rings. This will reduce bore wear since two O rings press against the bore instead of a steel pin. Symptoms usually develop around 60K miles along with solenoid block error codes. The case design had a manufacturing flaw since the servos don't move in a linear fashion. They move a little to the side. Steel pins scraping against a cast aluminum case create aluminum dust which clogs the solenoid block & valve body.

 

[david56780]

Do the O-ringed pistons actually help reduce wear?

The reason I wanted to try check the wear is because Im well past the 60k mark with no problems. Only the slight delay in gear change described above.

Without doing a search, I assume the problems with aluminum particles clogging the valve body can be fixed with a rebuild or clean of the VB?

 

[BrooklynBay]

The manufacturer calls these transmissions "sealed", and doesn't want anybody to touch them for over 100K miles. Frequent fluid & filter changes will prevent debris from accumulating in the valve body & solenoid block. The servos with O rings reduce wear because the O rings make contact with the bore instead of the steel pin. This reduces wear & debris plus it seals the irregular bore to prevent pressure loss.

 

[david56780]

Thanks BB.

There doesnt seem to be too much feedback on how well the o ringed pins last. Ive PMed someone who installed them a few years ago to see what they say about them.

Does anyone have any feedback on how well the o-ringed pins last?

 

[BrooklynBay]

It might be a good idea to check the O rings for wear occasionally. I know that it's not easy to get to, but if it helps the transmission last without requiring a rebuild, then it's worth the effort. I'm sure that they could last a few years before requiring a replacement.