The syncros were reassembled...
The syncros were reassembled first. Here's the trick: Lay the inner hub on a syncro stop ring, then engage the clutch sleeve over the hub. Drop in the three struts, then wind in a spring. Flip it and wind in the other spring, starting at another strut. The long side of the inner hub goes forward on both syncros (shift fork side of the 1-2 sleeve, and rounded side of the 3-4 sleeve).
Rather than send it back to the junkyard, we decided to sleeve and rebuild our tired aluminum-case 833, making it bulletproof in the process. Sleeving the case isn't the place for meatball surgery. The case needs to be bored out to precise size, and more critically, in the precise location to pull this off successfully. This means a Bridgeport mill and someone who really knows how to use it to get the case prepped; a lathe with some experience behind the handles to whittle out a pair of precision-sized bushings is a must as well. As for the rebuild part of the job, servicing the overdrive trans is pretty much the same as with any 833: The usual replacement wear parts are the bearings, seals, gaskets, thrust washers, and syncro brass. The hard parts are just reused if they pass the eyeball test. Want an Ali-cased 833 that lives? Make friends with a machinist, break out the wrenches, and follow the photos.
| Torque Specs |
| 833 overdrive four-speed |
| Pinion bearing retainer | 30 lbs.-ft. |
| Extension housing bolts | 50 lbs.-ft. |
| Shift lever nuts | 18 lbs.-ft. |
| Trans to bellhousing | 50 lbs.-ft. |
| Shift cover | 15 lbs.-ft. |
Now the gears and syncros...
Now the gears and syncros go back on the shaft. Don't forget the snap rings, and press the bearing on to finish the rear of the shaft.
Bushing Bash
Whatever the reason behind the production aluminum-cased overdrive 833's sloppy, loose-fitting case-to-countershaft clearance of .005 inch, the bottom line is that under any kind of punishment, it's a ticking time bomb. It's only a matter of time before the case pounds itself apart and it's over. Bushing the case is the single biggest improvement to beef-up one of these trannys. It won't equate to the brutal 18-spline Hemi four-speed's strength, but we're talking seriously increasing the odds of survival in performance street applications. Bushing the box is a precision machining operation that involves boring the case to accept the sleeves and turning out a set of precise bushings in a lathe.
The basic working specs for the repair bushings on this tranny starts with sizing the inside diameter (I.D.) of the bushing for zero clearance with the countershaft. The bushing outside diameter (O.D.) was machined to 1.25 inches, with a step register .100-inch larger than the basic outside diameter (to 1.35 inches), .100-inch long, machined on one end of the bushing to locate it in the case. One bushing requires a notch for the countershaft key and both need notches at the inside edge corresponding to the slots in the thrust block face inside the case; otherwise, it'll be impossible to assemble the transmission.
The tranny case was bored for a .005-inch interference fit with the bushing, with a corresponding relief cut .100-inch deep, and 1.365-inches diameter to accept the locating register in the bushing. It's critical that the centers of the bored holes in the case are precisely located in order to keep the countershaft parallel, in line, and at the correct clearance to the mainshaft gears. A few thousandths out, and either the trans won't go together or the countershaft won't drive in. In this case, we indexed the center off the unworn portion of the countershaft bore closest to the mainshaft. Finally, make sure good machinist practices are followed, all of the edges are chamfered, and all measurements are dead-on. Hey, if a magazine guy can do it himself, it shouldn't be too tough to find a real machinist to handle the job.
At the front portion of the...
At the front portion of the shaft, we have the overdrive gear, the 3-4 syncro assembly, and a snap ring to pin it in.
We drove out the extension...
We drove out the extension housing bush and knocked in a new one. A simple driver was made with a couple of sockets bolted together with a washer in between to drive the edge of the bushing. The supporting (inner) socket fit loosely inside the bushing with tape wound around it, since the bushing contracts as it goes in.
Next, the assembled mainshaft...
Next, the assembled mainshaft goes into the extension. The snap ring between the bearing and first gear is compressed to lock it into the extension housing's groove.
The cluster gear is loaded...
The cluster gear is loaded with new roller bearings and spacers, using heavy grease to hold them in place. An arbor shaft must be inserted to hold all the bearings in position while the cluster is installed. The shaft should be just long enough to support the thrust washers at each end of the cluster-but no longer-and 15/16-inch in diameter. We cut an old jack handle to make this one.
Line up the tabs on the thrust...
Line up the tabs on the thrust washers with the slots at the thrust surface of the case and lower the cluster gear to the bottom of the case. The arbor shaft should be inside to hold the bearings and thrust washers in place.
With reverse gear about midway...
With reverse gear about midway and the 3-4 syncro sleeve edged forward (don't overextend the sleeve; otherwise the struts will dislodge or fall out), angle in the extension assembly, and don't forget the gasket.
The input pinion is prepped...
The input pinion is prepped by pressing on a new bearing and loaded with new roller bearings inside the gear. Make sure the front syncro stop ring is in position, and slide in the input pinion. The bearing retainer gets a new seal and gasket.
Flip the tranny upside-down...
Flip the tranny upside-down and the cluster gear will end up close to alignment with the countershaft bore in the case. Make sure the bores of the cluster gear, thrust washers, and case line up, and that the keyway grove in the shaft is in line, then drive in the countershaft. Since we didn't include the steel plug provision used with the shorter floating countershaft in our bushings, we went with the longer, standard 833 countershaft. The long countershaft will end up about .100 inch from the front of the case when the rear is driven in just flush. A fill of silicone at the front end of the shaft will stop any potential oil seepage. Driving in the countershaft will push the arbor out the other end.
To finish it off, the reverse...
To finish it off, the reverse detent plugs and backup light switch go in, then the side cover. The 1-2 shift fork gets hooked into the syncro first, then the cover with the 3-4 fork is lowered in place, and the 1-2 fork is guided into the shift lever. The interlock scissors must be pushed back with a screwdriver to catch the shift fork for the cover to drop in place.
This time around, our 833...
This time around, our 833 will be ready for action when it's bolted under our '69 Dart.
Bore the tranny case first,...
Bore the tranny case first, since the bushing can be made to fit if there's a goof. The hole was bored 1.245 inches in diameter all the way through, followed by an outside relief measuring 1.365 inches in diameter and .100 inch deep to take a step register in the bushing. The critical part here is to locate the centers properly before firing up the mill.
The bushings were whittled...
The bushings were whittled from solid steel bar stock in a lathe. First, the I.D. hole was bored to give zero clearance to the countershaft, then the O.D. was machined to 1.250 inches to give a .005-inch press to the case. A .100-inch-long step register was machined at one end of the bushing to 1.350 inches, then the bushing was cut to length and the same thickness of the case casting.
Here are the raw bushings...
Here are the raw bushings just off the lathe. Note the step register on one end. The fit to the shaft was perfect; no clearance, but a tight slip-fit. The inside edge still must be notched to match the slot in the case's thrust face to allow the countershaft and thrust washers to go in.
The case was heated to 300...
The case was heated to 300 degrees in a conventional oven to ease the press-fit, and the bushing was squeezed in with a jackscrew. Some Loctite wicking threadlocker was allowed to seep in; fat chance that these were going anywhere!
A notch (pointer) is required...
A notch (pointer) is required for the countershaft key, only at the extension housing side. This can be performed on the mill with the bushing in place.
Here's the inside view. Note...
Here's the inside view. Note the two notches in the bushing corresponding to the slots in the thrust pad of the case. The notches should be made before the bushing is installed. The bushing must be flush with (or slightly below) the thrust pad, or the thrust clearance will be fouled up.