Sleeved OD servo

[GRWeldon]

I just started disassembling the tranny from my 97 4.6 Tbird. I was surprised to find that the OD servo had a sleeve on it. I have read about these in transmission forums, but I was just skimming. I have a question or two that some of you kind folks might be able to answer.

First, is it a good thing or a bad thing or indifferent that my OD servo has a sleeve?

2. Did some 4R70W trannys come from the factory with a sleeve or is it indicative of being worked on after leaving the factory? The 1-2 and 2-3 accumulator pistons in this thing were both aluminum with O-rings instead of the bonded design. I would think that those would have been replaced if somebody had been inside the valve body.

3. What does the sleeve do and do I have to re-use it or do I have a choice?

Thanks y'all...

 

[Grog6]

It's pressed in iirc.
Is it this piston,


Or this one?




Note this does not repair the pin bore, that's different kit.

Or possibly this one:




There are tons of problems with the 4r70w, and if this was worn out it's a high mileage transmission that's seen a lot if interstate traffic. Probably a State Trooper, lol.
I'd take a careful look at that trans; Don't make Any assumptions, check everything in the VB snd direct clutch carefully. Check the play in the planetary gears. Replace ALL of the torringtons and bushings. Double check the direct clutch basket for grooves from the dogs on the plates. Sonnax makes a killer replacement for the basket, but racecar, it's pricey. If the sleeve comes out, post a pic of the bore under it. I think the piston for the sleeve is a smaller diameter, you do not want that. If for some reason you don't need it, use one of the others.
Most problems in this trans with od are with that pin bore; I've learned if there's slop in that bore, toss it and get a new case. A smoked direct clutch, odband, and cleaning the crap out of the tc and system is way more expensive than a $200 transmission.

The stock tune, on the interstate will do a constant 3-4 and 4-3 shifts as you go on and off throttle.The egr does the same. The difference is between the od band being clamped (OD),or loose (3RD, on the outside shell of the direct clutch.This is a Heat machine; if you watch the trans temp while it's doing this, it will go hot enough to boil over the radiator from the cooler in the radiator.
Carbon fiber, not kevlar, OD bands are best. Get your stock tune changed to require 75% throttle for a downshift, and a 5-30 sec delay on upshift at low throttle.

 

[GRWeldon]

My piston is the first one pictued. The sleeve is installed over the piston, the the sleeve goes in the bore. I believe the 2.7" updated OD servo piston (AOD standard) fit's in place of the sleeve, but I won't know for sure until the rebuild kit gets here. At least that's what I've been reading. It freaked me out to see the sleeve because I don't think the tranny on my 95 Cougar was that way. It was about 20 years ago when I did the J-mod on it so it's entirely possible there was a sleeve in it, I just don't remember. I DO remember putting the 2.7 OD servo in it though...

 

[Grog6]

I've only seen the sleeve in one, and it's pin bore was oval. It was a major fail. The jy gave me a new one, I gave them back a 96 core, lol. I think I got $10 for the aluminum.

 

[Grog6]

Both the o-ring, I pick my battles carefully, that's not one I'd willingly do. I'd be worried every time it hit OD, "is it failing now?" Watching the temp and speedometer will tell you quick.

 

[GRWeldon]

Both the o-ring, I pick my battles carefully, that's not one I'd willingly do. I'd be worried every time it hit OD, "is it failing now?" Watching the temp and speedometer will tell you quick.

Well, during inspection I found the pin bore for the OD servo to be properly clearanced... about .002 or so...perfect. BTW, I have a 40-year background starting from machinist, toolmaker, tool designer, cnc programmer and ending with manufacturing engineer. I think I've said this before... folks are probably tired if hearing it, but I'm certainly proud of my career. All that history to say that I know what .002 clearance feels like.

As you probably know (I had to find out by chsnce) the 2.7 dia. OD servo perfectly replaces the 2.5 w/sleeve. I think I mentioned that I will go with the pin with O-rings anyway. I don't have any concerns with the servo failing unless it's the lower-end Chinese crap instead of the higher-end Chinese crap we get from out reputable transmission parts dealers. I'm sure the 2.7 will do a much better job.

BTW...the tranny I am rebuilding was a known "working" transmission with no suspected issues. I'm sure I will find damage in the one I'm replacing when I pull it apart. I've described the symptoms before, but I've put over 2500 miles on the tranny going to Michigan and back to Alabama and now it's starting to slip out of overdrive at random times for no apparent reason. Acts like it's low on fluid, but it really isn't.

Now that I've been inside and rebuilt one, it will be interesting to see what I'll find having all the new knowledge.

 

[supergordo]

The sleeve was used in the 1995 and earlier transmissions. Just buy the later model OD servo and throw away the sleeve and the old servo. The larger diameter servo will fit in the case perfectly and offer more holding force on the OD band than the sleeved one.

 

[Grog6]

You really need the one piece teflon seals on the direct shaft. IThat's what makes 3rd flakey. 4th is both it, an the od band, so two places to fail, lol.

 

[GRWeldon]

The sleeve was used in the 1995 and earlier transmissions. Just buy the later model OD servo and throw away the sleeve and the old servo. The larger diameter servo will fit in the case perfectly and offer more holding force on the OD band than the sleeved one.

About the 2.7 servo, I think I covered all you said in my post. Parts have been bought for over a week. The transmission I'm building came from a 97 with 96K miles. I may not be the original but I would think it is...so 2.5 and a sleeve in a 97?

 

[GRWeldon]

You really need the one piece teflon seals on the direct shaft. IThat's what makes 3rd flakey. 4th is both it, an the od band, so two places to fail, lol.

I used one piece Teflon seals on the direct shaft...

 

[supergordo]

About the 2.7 servo, I think I covered all you said in my post. Parts have been bought for over a week. The transmission I'm building came from a 97 with 96K miles. I may not be the original but I would think it is...so 2.5 and a sleeve in a 97?

In mass production I certainly wouldn't put it past Ford to have used up the 2.5 and the sleeves if they had them around. Or use eariler transmissions that they had lying around too. The only other factor would be the diameter of the locating pins on the VB. 95 and eariler are 1/4", 96 and newer are 1/8" iirc.