Direct drum blowout?

[topless87]

I'm new to this forum and this is my first attempt at rebuilding the AOD out of my 87 vert. The car is stock, except for the mass air swap.
I've rebuilt two C4s for my other vehicles with good results; they dont leak and they actually turn the drive shaft!
Interesting find was that the direct drum snap ring (not pictured) was just loose on the shaft and the outer rim of the bearing was broke off. The spacer/washer surface look like it was peened. Could all this have been the cause of the chunk blown out of the piston seal?
http://members.cox.net/cnv/direct%20seal%20blow%20out.jpg
The frictions were/are toasthttp://members.cox.net/cnv/discburn.jpg
And the intermediate retainer spun/snap ring broke
http://members.cox.net/cnv/retainer%20break.jpg
And the sprag got beat uphttp://members.cox.net/cnv/Sprag%20wear.jpg

I really didn't abuse the thing...............much. But I also don't know why the snap ring on the direct wasn't attached/locked.
Anyway, my parts will be here by weekend for the rebuild. Nothing exciting. New frictions and steels, complete bearing kit, blah blah. I'll be adding the Sonnex valve per SilverFox's article. I had thought about the A+ servo but for a weekend summer driver, I couldn't justify the expense yet. Any tips/tricks appreciated. Thanks in advance.

[SilverFox]

The retainer spun due to snapring failure as common....make sure and replace the sprag and the retainer and plate.....I would reccomend a Mechdidoe upgrade myself, however on a budget, the 7 roller is still reliable up to 300HP, just needs a better snapring.

Also in pics one, I ASSUME, you mean the dirrect clutch spring retainer snapring was loose on the shaft....this failure stopped the piston from returning to the bore and smoke the dirrects I see. I would dissasemble the rear hub (snapring on back) to dissasemble the dirrect from the hub and inspect the snapring surface, groove, and face real well.....you may need a new drum as you would not what this to happen again.

I would say this AOD has seen it's fair share HIGH MPH on the hiway or drag strip since it was new. Snaprings don't just fly off at 60mph....however 100+ gets scarry for them :)

Good luck, looks good so far.
DO INVEST IN AT LEAST AN A SERVO, I am getting them for about $10 at my local shops when they are available.....I always buy out thier entire stock when they have them.....hell, I could sell them for 7x that price if I wanted.

[topless87]

Thanks for the reply. Yes, I meant the "direct clutch spring retainer snapring". It wasn't in its groove, and was probably walking up and down the shaft. The drum has been seperated from the outputshaft and soaked in kero to help loosen the gunk. I'll get a mirror on the groove for a closer look. Thanks! I've only had this car for two years, so the internals tell a little more history of the trans.

I'm still a little confused about checking end play since I don't own a depth micrometer. Any ideas or substitute suggestions welcomed.


...............
Good luck, looks good so far.
DO INVEST IN AT LEAST AN A SERVO, I am getting them for about $10 at my local shops when they are available.....I always buy out thier entire stock when they have them.....hell, I could sell them for 7x that price if I wanted.
I imagine a call to local shops here in town might reveal a bargain on an A servo, unless your offering to liberate yourself of one ;) .
I'm just not ready to toss an additional $130+ for an A+ into this rebuild.

[SilverFox]

I will see...

As for endplay...simple, place a vice grip on the input shaft flush with the stator support (the shot stubby shaft) with the pump torqued down and the factory or washer of choice in place. Rest the trans on the floor on the tailshaft....the internals should chinch up and push the output shaft up and you will be able to measure with a feeler guage how far the input has moved off the stator...this is your endplay. I like my endplay tight, with just enough movement to say it is there....that is just my opinion...others say different.

[topless87]

I like simple.
The C4 guys suggest tightening clearances up on C4 clutch packs at .005 per friction. Is this practice also reasonable for the AOD? The AOD rebuild manual asks for .05 - .067 on the direct drum which has 5 frictions. This would be considered loose by C4 builds.
5 frictions x .005 = .025 for a direct drum plate to snap ring clearance? Would tighter clearances present issues?

[SilverFox]

I like to hit the .025-.05 on the forward and dirrect. Remember, the dirrect clutches and steels spin differnt speeds without pressure ALL THE TIME in 1 and 2, so staying in the .05 range is good idea.

[topless87]

I don't seem to be able to find an intermediate retainer plate. I have the Sonnex 2 piece ring. My plate isn't REAL bad. The tangs are dog-earred, and some scoreing on the inner ring.

[SilverFox]

your local trans shop should have one, if not they should be able to get you one in a few hours.

There is 2 styles, you need the roller early model with square tabs.

[topless87]

Made progress over the weekend (despite the rain)! I had to use one of the better old steels between the pressure plate and last friction. The rebuild kit from bulkpart came with 6 slightly thinner steels but not thin enough to get the 6 frictions in my 5 drum. I pondered using two older steels as a pressure plate but I've read that a steel can spin sometimes in the snap ring groove :shock: . The sprag retainer plate and 2 piece retainer looks good. Most of the VB valves were a bit*h to get out and cleaned up. Sonnex boost valve went in without trouble. Forget trying to give the valve a slight twist when installing, as the VB itself is "L" shaped on that corner.
Putting a call into Baumann for the recal kit.
I'm still not sold on at least an A servo upgrade. I've got a B in there now. We'll see.:???:

[SilverFox]

for stock duty, it will be fine unless I get another in soon for you.