what part are ya gonna break next ?
learnin' stuff is fun !
just don't store all your info in your brain, then get old [like me]. it gets lost there.......
just my experience - your mileage may vary.

Hopefully I’ll get to find out soon but I only wanna break traction! I got the old trans out today. Autopsy is tonite but I don’t anticipate finding anything spectacular inside. At this point I’m basically going to swap out my good valvebody, make a front clutch restrictor for the new case, and build up this other ‘77 case I got with most of the guts from the other and some goodies from A&A whenever they arrive in the mail.

My dad always said if you’re gonna do something do it the best you can- I think windowing the case is about as far in that direction I want to go. Carnage is fun until you need a broom and stitches.

Autopsy complete. Ish. I didn’t know if maybe something inside locked up and caused the slip yoke to get a nasty shock load.

The sprag was in perfect health but after I pulled the snap ring the gear train still didn’t want to come off the output shaft. I might hammer it off since it’s scrap now anyway just to see what’s going on in there. I suspect it’s just banana’d.

I hammered (plastic deadblow) the gear train off the output shaft to see what was going on in there.

It looks like the aluminum splines on the front planetary gearset were starting to twist? I’m thinking this might have happened when the power going to the broken yoke/off center driveshaft turned into a shock load on the output shaft- more like evidence of the failure than a possible cause?

Ok she’s all together. I ended up with:
New A&A iron front drum.082 front clutch clearance, 5 red clutches flat snap ring
Front clutch case channel restricted with a drilled dorman plug like the beat trans case got with the tf2 kit
Re-used forward clutch drum from old trans- red clutches & kolene steels still look great.
Re-used kevlar bands still like new after 100 miles.
A&A billet rear servo, tf2 blocker; 2 turns out
A&A front servo link bar, 4.2 lever, controlled load defeated w set screw 1.25 turns out
.040 endplay- higher than I was shooting for but well within specs per Munroe book
Servos and clutches all air check good
Accumulator retains spring between piston and valve body as per John Kunkel over and over in a hundred threads on the search function. It shifts plenty hard already with decent throttle application.
Double checked that the deep pan pickup extension was clocked properly 😉

It will be interesting to see if I can feel the difference with the controlled load blocked in the kickdown piston and the 4.2 lever.

Pop for a steel front planet?

This is what I call a wear item in my race trans. When they won't slide off it's time for a new one. Look at it from the rear. Are the splines helical? Never had one completely fail. Current one has about 200 passes on it and still slides fine. I keep thinking about upgrading but since it hasn't failed I'll stick with it. I've only replaced one in 550 passes.
Doug

Thanks fellas

I appreciate the benefit off your experience and don’t think I didn’t look at steel spline planets or steel front drums.

I replaced it with a healthy tight 3 planet out of my new trans core- also a 77. Hoping to get a few sets of tires oit of this trans build with steel 1350 yokes behind it before pulling it again. As far as I’m concerned the old output shaft and front planet are wall art now.

She’s all built up. I’m off on weds just gotta stab it in and hope my new driveshaft is done soon!

Kinda tight. 1.75 would be better.

radar, does the billit rear servo come with the HD retainer plate ? is that plate heavier material, or just stronger ? if it's heavier, how much thicker is it ?
i have always wondered about that, but i never had one in my grimy mitts to measure, and of the guys i personally know, i never thought to ask them before they had it installed.

mr. kunkle, what is your opinion on using ALL of the billet servo pistons instead of just the reverse and accumulator ones ? prettiness aside, of course.
also, is any one supplier of these better than the others, or is just one outfit making them, then differentiating the companies by just the anodizing color ?

Personally, I see no need for the billet front servo and accumulator piston if you have serviceable factory parts. Sure, there are documented cases of failures of the servo but it's not epidemic.

The heavy rear servo spring is known to distort the stamped retainer, the retainer supplied with the billet servo kits is heavier.

As for the accumulator - the aluminum ones - agreed, but the glass reinforced plastic ones should be replaced.
We regularly saw those broken or on their way out - in core coming in from the field.

John thank you so much for carefully reading my buildup specs and offering a helpful change on the kickdown band adjustment. Plus it’s a real easy one to fix!

Moparax like John said the kit replaces the flimsy steel collar with a nice billet piece. It’s not overly thick but plenty to stay rigid and do the job. I had to re-use the blocker and spring from my tf2 modded stock setup but the AA kit had the piston with seals installed, the retainer plate, and a new snapring. Plus photocopied instructions.

It is so nice to have the trans buttoned up and be able to make sawdust and do metal fabrication again in my little garage!

Much thanks for all the support here

Radar

Yeah, I shoulda said factory "metal" piston. The plastic ones were a bad idea.

Hey while we’re talking about accumulators- I have seen a bunch of different blocker designs from 3/8” to 1/2” thick rods. The A&A blocker photo in the Munroe book is a piece of tubing like motorcycle handlebar or something.

All are 2 15/16”-3” long. I understand that John always likes to keep the spring and not block it to keep from breaking stuff/accelerating wear. My ‘77 trans (both of them) had springs between the valvebody and piston but none under the piston. I kept it there like John says despite the temptation to possibly chirp the 1-2 shift at light throttle?

Anyway my confusion is if I were to block it how does the blocker work if it is just rattling around in there? Or does it just cock at an angle and stay that way? Or does it limit travel to just a teeny tiny amount so the piston never gets the speed up to slam around?

Thanks

Removing the spring between the VB and piston WILL NOT firm the 1-2 shift, the accumulator's cushioning effect on the 1-2 shift is strictly hydraulic i.e. as long as the piston is free to move it will cushion the 1-2 shift....spring or not. Blocking the piston simply stops the accumulator's function.

Blocker rods are typically 3" or slightly less. Tube or rod will work, the MP blocker is tubing. It's important that the blocker doesn't push the piston so far out of its bore that it keeps the VB from seating properly against the case.

I didn’t mean to imply that simply removing the spring would block the piston- I meant I left the spring rather than blocking the piston. I am aware that you constantly and tirelessly work to dispell that myth about simply removing the spring or springs.

It just seems wierd to throw a piece of metal in there that is thin and free to settle into a diagonal position. I guess the piston doesn’t have room to move very far? And the blocker would drop in under the piston with the goal of positioning it as close to the valvebody as possible?

The piston is hollow, so no chance of the blocker cocking enough to cause a problem. Even if the blocker was a little short, gravity would keep it pretty well centered in the piston cavity.

I got some help and the trans install went smoothly yesterday. I filled it up with Type f and went around the block today and heard a scary clunk.

The tailgate wasn’t properly latched and fell down 😂

Most of the changes were beefing and reliability- I suspect the increased kickdown lever ratio and defeated controlled load section of the front servo are going to be subtle if I can even tell at all. I only putted it a half mile so I don’t know if the shifting personality changed much but I do know I have reverse and all three gears.

Thanks for all the help!

Radar