I've checked a number of sources now for clearance specs for rear output shaft for the transfere case, none found.

How much play are with talking about? (1/4,1/8 inch?)

You're going really quite hardcore with this gearbox Frank, carry on at this rate and you'll be above factory QA specs.

As for the lone post, it was an interesting read, just coz no-one immediatly ran to your aid doesn't mean it's a bad post.

No, I'm talking about end clearance between the bearing and the tailshaft cover. As it now sits with the new rear cover, I have negative .002" (including the gasket) - which means when puled up tight is deforming either the aluminum cover or the bearing cage. Several different spacers are available from MMC, so I've ordered a 1.02mm spacer that should give me positive .002" end clearance, which seems ok to me.... the next spacer would result in .006", which seemed a bit too much, but without an OE standard I'm shooting in the dark. You have to see how it's set up to understand what I'm asking and it's hard to explain (for me)... the shaft assembly is kept from moving forward by a snap ring on the rear bearing of the output shaft... it's kept from moving to the rear by the tail cover - so the bearing is sandwiched between the two limiters. With too little end clearance, it's possible that the snap ring deforms enough to keep the bearing cage from distorting, but I'm not certain - seems better to have just a little clearance.



When I tear something down, my goal on reassembly is AT LEAST factory QA standard.... My inexperience probably causes me to overlook some things, but I enjoy tinkering and poking around to see how things work.



What I said about t-case work being for loners was intended to reflect the lack of trouble with these cases - trouble that would necessitate many others having torn them down. By contrast, nearly everyone knows how to replace a starter. <img src="/forums/images/graemlins/lol.gif" alt="" />

Frank

Look Familiar?



Cleaning takes the most time.



The 2.85 input gear goes in.





It needs its snap ring for the input gear. However it also needed a .093" thick spacer behind the snap ring. Not sure if all the 2.85 gears need this or not. It took a few tries to get the exact thickness, access to a lath really helped.



snap ring in place


The gears waiting for the mainshaft to be inserted.


A bunch of steps skipped....

Actually quite a few people have been into the transfer cases to rebuild and swap in the 2.85 gears.


Kevin

Yes - it does look familiar - and yes - a bunch of steps were skipped. <img src="/forums/images/graemlins/lol.gif" alt="" /> That one's cleaner than I got mine. <img src="/forums/images/graemlins/kewl.gif" alt="" /> I figure the gears will grind up any residue. <img src="/forums/images/graemlins/wink.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" />

I'm waiting for a .040" spacer for the rear output shaft cover.... hope I guessed right for gasket torquedown thickness.... I'm guessing a maximum of .002" on a .010" paper gasket.... anyway, it'll be looser than it was and I guess the snap ring has a little give on pressure, but not much since the bearing is a slip fit.

Frank

Frank, here's a compressed gasket measuring tip. Buy two of the same kind of gasket. Cut off enough of one to provide a cover-case metal to metal measuring point, preferably for a vernier caliper, but I bet feeler gauges will get you close enough. Torque down the cover and sacrificial gasket and measure, leaving out any guts that could prop up the cover and pooch the measurement. I think a gap in the center of a fairly straight edge would give a truer measurement than a corner, and I figure a .25" wide V notch in dhe edge of the gasket is enough space. I've use this to measure compressed head gasket thickness. Kid's modelling clay has been useful for measuring stuff like piston-valve clearances and squish volumes, and could check shaft-cover clearance in a case like this. I set the minimum clearance on the depth part of the vernier caliper, and punch test holes in the compressed clay at the point of interest. Any test hole without the full rectangle imprint of the end of the caliper beam is too damn tight. I neglected this step once on a 301/2 SBC, and at 8000rpms, the piston finally tapped the valves that were at long last floating or bouncing off the seat, bent them and stuck 'em open, and those nice new MT titanium rods sawed the block into pieces, literally. Took the motor out in about 8 or 9 "big" pieces, and too many little ones to count. It made an impressive (and expensive) sound when it let go...

0 to .0039" (0 to .1 mm) for the bearing spacer that lives near the speedometer drive gear according to the 1984 manual... (Edited to account for a misprint in the 84 manual).

Tighter is better, I dont think the gasket is going to compress 20% from a measurments taken with a caliper with a slight bit of pressure.

I would allow .001" for the gasket.... And the snap ring may just give that much <img src="/forums/images/graemlins/shiner.gif" alt="" />. That should get you close enough.

Kevin

Eddy - good idea to use the extra gasket - I measured the compressed one that came out and compared it to the new one - not a lot of difference.... maybe .001".

Kevin - that's exactly what I'm thinking - maximum of .002" and I'm allowing that much in the overall scheme. The next thinnest one allows .006" pre-gasket-compression (too much) and the next thicker one is a negative number (too little) - so the .002" (pre-gasket-compression) will have to do. I figure between compression and heat swell, it'll end up at "0" bearing play... if heat causes any further negative clearance, the snap-ring might allow for it. I can't believe there's no factory spec for this - but apparently there's not. My opinion (fwiw) is 0-.002" is ok - but don't ask why I think so - it's just a hunch. <img src="/forums/images/graemlins/notooth.gif" alt="" />

Frank

The factory spec in the 87 and 89 manual is 0 to .004", its in the manual tranny section, Looks like they forgot the spec in the auto section.

The 84 manual has a misprint, they call out 0 to .1 mm / 0 to .04"... Should be .004".

In case you missed it....

Spec from factory for the rear cover = [color:"red"] 0 to .1 mm / 0 to .004"[/color] Section 21, page 48 in the 1989 manual.

I knew I had seen this in my books before since I had checked it when putting my case together. You just need to know to look in the wrong section <img src="/forums/images/graemlins/confused.gif" alt="" />

We need to write an addendum to the manual, what sections to skip and when to jump to the wrong section. <img src="/forums/images/graemlins/cyclops.gif" alt="" />

Kevin

Thanks! I thought I had seen it when I changed the tail cover, but this time I looked all through the t-case section and didn't find it. Anyway, I should be good at .002", providing they include the gasket in the clearance spec.



Yes - and it needs to include a cross-reference to a list of correct specs and procedures for the mistakes. Writing that reference might be a full-time job. <img src="/forums/images/graemlins/wink.gif" alt="" />

Thanks again,
Frank

After a couple of parts waits, it's done (I hope) - shifts slick back and forth between 2H and 4H, but won't go into 4L - hope it just needs a little oil and slight rotation of the gears to mesh, but haven't tried it. Sure is purty:





Now I have to quit stalling and start INstalling... the transmission and t-case. <img src="/forums/images/graemlins/baby.gif" alt="" />

Frank