Splitting the Case: Getrag 5-Speed

How to split the case on a  Getrag 5-Speed

If you have purchased a Getrag from a FWD GM car and want to put the plastic gear into it for the speedometer, it is not a very difficult job if you are aware of a few tips and have the instructions to reassemble the detent assembly.

Inside the bell housing there is a large rubber cover.  In the middle this cover is rubber only.  This is where you will need to drive a screw driver into it and pry it out.  If you do this carefully you can hammer it straight and silicone the hole and reuse it.  If not you will need to replace it.  Cost is about $10.

With this cover removed you will need to remove the two bolts and carefully pull the detent parts (sprints and detent balls) out being careful not to loose any of the parts.  Put them in a bag or container.

On one shift rail you will see a steel washer.  This is a tee bushing.  You need to pull it out.   Using 2 small Allen wrenches, walk it up and remove it.

Now remove all the bolts that hold the case halves together.

You can now pry the cases apart.  There are 2 places where a pry bar can be used.  If it cannot be separated, a thin tapered wedge can be hammered at the split seam.  Do this at a high spot (up where the slave cylinder goes) as to not cause a leak upon reassemble.   Generally, once the seal is broken, the case halves easily come apart.

You can now pry off the steel cog and push the plastic speedo gear on.

Clean the mating surfaces and use Locktite 518 sealer.

Stand on the small case half side, set in the differential assembly and put the case halves back together.   Apply 15ft/lbs on the bolts.

The instructions below illustrate how to reinstall the detent assembly.  Shift through all the gears and turn the input shaft to check for any problems.

Reinstall the rubber cover.  The transmission hold 2 quarts of 5W-30 oil.

How to reassemble the Detent Assembly

Note: Position shift rails so the 5th gear shift rail (197) is 1/4" BELOW the other three shift rails - that MUST be at the same height (neutral position).

1. Reverse bushing (167).

2. Assemble interlock pins (168) and springs (170) into bores in detent holder (169) retain with petroleum jelly.

3. Detent holder and spring assembly (169) with the detent ball (171) for the reverse shift rail (183) (Bottom figure at right)

4. Detent balls (171), using a small screwdriver (View B of bottom figure)

• Install the detent balls for the shift rails in the following order:
  -  1-2 shift rail (190)
  -  3-4 shift rail (184)
  -  5th gear shift rail (197)

5. Position holder (169), using pry to align holes with threads.

6. Bolts (175), 9.0N*m (84 lb in).
   BE SURE shift rails are in the correct detent positions.

7. Protective cover (174): tap until seated in bore.

8. Bearing (22).  Apply high temperature grease to inside bore.

20.   HOUSING, CLUTCH AND DIFFERENTIAL
22.   BEARING, CLUTCH DISENGAGE.
167. BUSHING, REVERSE SHIFT RAIL
168. PIN, INTERLOCK (TWO)
169. HOLDER, DETENT
170. SPRING, DETENT (FOUR)
171. BALL, DETENT (FOUR)
174. COVER, DETENT HOLDER
175. BOLT (TWO), 9 N*m (84 lb in)

NOTICE:  POSITION SHIFT RAILS SO THE 5TH GEAR SHIFT RAIL (197) IS 1/4" BELOW THE OTHER THREE SHIFT RAILS - ALL THREE MUST BE AT THE SAME HEIGHT.

A. ASSEMBLED DETENT HOLDER AND SPRING ASSEMBLY 169 (VIEW A) WITH SPRINGS 170, PINS 168 AND THE DETENT BALL 171 FOR THE REVERSE SHIFT RAIL 183.

INSTALL THE DETENT BALLS WITH SCREWDRIVER (VIEW B):

B. 1-2 SHIFT RAIL 190.
C. 3-4 SHIFT RAIL 184.    
D. 5TH GEAR SHIFT RAIL 197.

169. HOLDER, DETENT
183. SHAFT, REVERSE SHIFT
184. RAIL, 3RD/4TH SHIFT ASSEMBLY
190. RAIL, 1ST/2ND SHIFT ASSEMBLY
197. RAIL, 5TH SHIFT ASSEMBLY