Repair. - TM-9-2520-246-340034

TM 9-2520-246-34

cover for cracks or breakage. Small cracks that do not

transmission is assembled. Mount the mainshafts in

extend into the mounting holes can be repaired.

test centers and check for misalinement at bearing

Check and clean out all tapped holes; mark for repair

journals and along the entire length of the shaft by

any damaged holes or broken off studs in tapped

using a dial indicator. Misalinement in excess of

holes. Use a honing stone to smooth out any

0.001 inch is cause for rejection. Inspect the splines

scratches, burs, or gouges on the gasket surface.

and reject the shaft if splines are twisted, scored, or

Carefully check the shifter shaft and poppet ball

obviously worn. Smooth minor defects with slip stone

bores. If the shifter shaft bores are seriously scored,

or honing stone. Install the sliding internally splined

gouged, or galled, the cover must be rejected. Clean

gears on the mainshaft and clamp the mainshaft

up minor imperfections with crocus cloth. Reject the

upright in a bench vise. Check each gear, in turn, for

cover if the edges of the poppet ball bores are chipped

spline clearance by inserting a narrow feeler gage on

or rounded.

edge between the splines. Refer to repair and

replacement standards contained in the respective

2-10. Repair.

chapter for each assembly. If clearance is in excess of

this established tolerance, check with a new gear and

a. General.

new shaft to determine whether gear splines or shaft

splines are at fault. Reject the part at fault. Check

(1) This section contains repair instructions for

wear on front and rear bearings.

the assemblies discussed in this manual. Because the

material and construction are similar, the repair

(11) Countershafts. Follow the same procedure,

instructions will be given in general form. If special

when applicable to the countershaft, as outlined above

repair is required, refer to Cleaning, Inspection, and

for the mainshaft. Use a honing stone to smooth out

Repair section of the respective chapter for the

any burs, gouges, or scratches. Pay particular

assembly.

attention to the section of the shaft that carries the

(2) Only high quality repairs are acceptable.

press fit gears, especially in and around the key slots.

Any deviation from the normal condition in this area

Makeshift or temporary repairs are not acceptable,

will cause considerable trouble when reassembling the

except in extreme emergencies.

gears on the shaft. Try the woodruff keys in the key

slots. If neither the key nor the slot is distorted or

(3) Small holes or cracks in assembly cases,

misshapen, the key will require only light tapping to

shifter shaft covers, or clutch housings may be

completely seat in the slot. Do not attempt to force

repaired by welding or brazing, provided they do not

the key into place; if difficulty is encountered, use a

extend into the bearing bores or mounting surfaces. It

new key.

should be noted, however, that these parts are cast

iron. A special technique is required to satisfactorily

(12) Input Shaft. Inspect the splines on the input

weld this type of material; ordinary welding methods

shaft for wear, twisting, or galling. Inspect bearing

and materials are not suitable. (Refer to TM 9-237.)

journals for wear. Determine that the gear teeth are

not cracked, broken, or otherwise damaged.

(4) Remove the short ends of any bolts or studs

broken off in tapped holes. Clean out and inspect all

(13) Shifter Fork Shafts. Check the shifter fork

tapped holes; retap where necessary. If hole threads

are stripped, or if holes are out-of-round, drill out to

shafts for misalinement by rolling them across a

next larger size and tap. Install a bolt or stud of the

smooth, level surface. Failure to roll, or rolling with a

correct size to fit the newly tapped hole.

bumping sound, indicates misalinement. Bent or

sprung shafts must be rejected, unless suitable

straightening equipment is available. Inspect the shaft

b. Handling After Inspection and Repair.

poppet ball detents for wear or damage. Reject the

shaft if detents are chipped or are not sharply defined.

(1) All parts, whether new or used, must be

lightly coated with lube oil (OE/HDO 30), ICE, MIL-

(14) Poppet Balls and Springs. Reject all poppet

L-2104, immediately after inspection and/or repair,

balls with flat spots and all weak or broken springs.

prior to assembly into the transmission. Oiling the

Use only those parts that are completely satisfactory.

parts gives them a rust-preventive coating and

facilitates the assembly operations.

(15) Shifter Forks. Inspect shifter forks, paying

particular attention to the lower fork ends. Bent,

(2) Make sure that all new gaskets and

broken, or sprung parts are to be rejected outright, as

replacement parts are available to replace those

repairs are impossible. Worn parts may be used at the

discarded.

discretion of the inspector.

(3) Check to be sure that all parts are at hand so

(16) Shifter Shaft Cover. Inspect shifter shaft

the assembly operations may proceed without

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