w126 Trans 722.303 - rebuild - special tools?

[SpecialDelivery]

I have a 722.303 that slips/flares from 2 to 3 and 3 to 4....modulator cranked all the way up, still not getting enough pressure. new modulator and pin going in hopefully this weekend, if I still cant get it right Im' goin to drop the pan and replace the bowden cable and put in the superior transmissions shift kit....

couple of folks have suggested I pick up a spare trans from the junk yard and down load the ATSG, take the j/y trans and practice on it / scrounge it for parts / put it in the car to see if it shifts right / learn how to rebuild it and then rebuild it myself...thereby having a fresh trans to put in the car and knowing how to do the job myself as opposed to being another trans shop "victim"

Questions are, am I insane for attempting this and are there any special tools ( I hear there are) which are required?

Thanks all for the feedback, encouragement and support!

[layback40]

Send Army a PM. he may help you with a manual.
From my own experience, You may need to replace a couple of clutch packs. Not too hard if you are technically minded.

[Stretch]

I haven't done a 722.3 yet - I did however write up a DIY for a 722.1(18) =>

http://www.peachparts.com/shopforum/diesel-discussion/304903-722-118-automatic-transmission-rebuild-monster-diy.html

It gives you an idea of what is involved - but your transmission is very different in several places!

As far as I can make out special tools are not required - special tools help - such as transmission stands and cradles. You will probably have to be inventive; yoghurt pots cut into strips help with brake band actuator pistons etc

Good luck and let us know how you get on.

[rs899]

One of the servos has a very stout spring, but you can deal with it without a special tool (just need a bit of ingenuity).

[DeliveryValve]

If you wanted to practice rebuilding a trans, that's a great idea. But I think for your problem, you might just want drop the pan and install new K1 and K2 springs either from superior or from the dealership.

I would do that first before attempting to rebuild the whole thing.


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[sixto]

DV, do you have the part number for a 722.3 K2 spring?

Thanks,
Sixto
87 300D

[SpecialDelivery]

sixto, from what I gather reading here, it's the same as the k1 part, and the superior kit is well...superior

[SpecialDelivery]

FYI Everyone following...

While my modulator WAS holding vac, I couldnt get more than 25 psi with the pin cranked all the way in. So I ordered one. I pulled the modulator to see if the pin was broken, it wasnt. It was oozing a rust colored liquid from under the black cap.



I installed a new modulator (febi/biltstien) and pin which had a longer base as well as overall length.



Then I hooked up the pressure rig, and it was (miraculously) reading at 42 psi at idle, dead on. Quite amazed I didnt have to adjust it.


I test drove it and the 3 to 4 flare is gone, still a slight on the 2 to 3...so I adjusted the VCV to put only 10" to the modulator at idle. Still a slight flare, which went away when the car warmed up.

BTW the modulator (from Fastlane, came with the o-ring seal and the rubber cap, no need to buy extras)

At this point the 2 to 3 is firm, clunks a little and I cant feel 3 to 4 at all.

I plan on tinkering with the VCV a little more but am quite happy that the problem is "resolved" and I dont need to rebuild the trans.

I'm debating on if I should install the "Superior Transmissions Shift Correction" spring kit I bought now or maybe at next fluid change or maybe sell it?

As always your thoughts, comments and ideas are appreciated!

[DeliveryValve]

Originally Posted by sixto

DV, do you have the part number for a 722.3 K2 spring?

Thanks,
Sixto
87 300D

This is what I've found.

For the 722.3

126 270 44 77 is firmer replacement for both K1 and K2

126 277 84 32 is an old number for the K2 and is thought to be a tighter spring.

For the 722.4 K2, but can be used on the 722.3

126 270 04 35
126 270 05 35 is thought to be a firmer spring than the "04" K2 spring.


There is talk of another firmer part number 722.3, perhaps related to part number 126 277 84 32.

These springs are fairly cheap, under 8 bucks for the 126 270 44 77 and under 6 bucks for the 126 270 04 35 and 126 270 05 35.


.

.

[Hit Man X]

$200-300 for the special tools to break down the two clutch drums, install seals, etc. Hell, I bet you could build your own jig or pay a local trans shop to break them down for you.

Buy yourself a fixture to be able to mount the trans vertically on an engine stand. I have seen them from $40-60.

I have the ATSG book, paperback, it is nothing to write home about. The 722.3 factory book is far better. I have had it for years, received it from a member her initially (Sixto maybe) and I have just sent it on to everyone else. Just know reverse is what usually dies in these making people seek shops that force you into an entire rebuild when you just need reverse clutches. I do think you will be able to solve your issues with the valve body kit and fine tuning.

[Dave Donaldson]

Great stuff,!!!,, saving all this good info for the day I rebuild mine 722.321 87 SDL,,(350,000 kilometers ) very slight flaring when cold ( 32 f and less) , when it heats up relatively speaking,, shifts so smooth,, picked up a spare 722.318 from a 87 300 td, 119,000 miles on it and will use it for practice and parts,,, yup I know it's a cable speedo on the 722.318 and the SDL has a digital speedo out put,,but up here these parts are like golden hen's teeth,, ,,,It's off the road for the winter, live in a rust belt,, but will pull the trans and eng. in Sept. 2012. Meanwhile I 'll be buying spares and new parts till then Cheers DD.
BTW I will have some extra parts from the 90 300 and 87 300 td,, for grabs that do not fit my car,, door panels tan,, interior bits,,

[SpecialDelivery]

Dave,
Mine was flaring when cold with 10 in/hg to the modulator, turned it down to 8 and it's good....try turning down the vac a bit or upping the pressure a bit! you might have to replace the modulator if you're not getting right line pressure at the test port!

Originally Posted by Dave Donaldson

Great stuff,!!!,, saving all this good info for the day I rebuild mine 722.321 87 SDL,,(350,000 kilometers ) very slight flaring when cold ( 32 f and less) , when it heats up relatively speaking,, shifts so smooth,, picked up a spare 722.318 from a 87 300 td, 119,000 miles on it and will use it for practice and parts,,, yup I know it's a cable speedo on the 722.318 and the SDL has a digital speedo out put,,but up here these parts are like golden hen's teeth,, ,,,It's off the road for the winter, live in a rust belt,, but will pull the trans and eng. in Sept. 2012. Meanwhile I 'll be buying spares and new parts till then Cheers DD.
BTW I will have some extra parts from the 90 300 and 87 300 td,, for grabs that do not fit my car,, door panels tan,, interior bits,,