4L79 Input housing / Drum assembly Instructions
*ANY questions please call (219) 577-6301
Step 1
Clean input housing and Billet cap with care, the threads on both the input housing / drum and billet cap are very fine and aluminum. We recommend washing and immediately applying new Atf to the threads and performing all press work with the cap on the drum. Atf has proven best in making the threads glide with ease with no galling, sticking or any other adverse effects. *Note the use of heat from a small propane torch will make the aluminum expand and contract very quickly and very easily. If you have any issues we recommend using heat during assembly or disassembly.
Step 2
*Note that the input housing and the input shaft have a “blind spline” used for lineup that both must be lined up before pressing. ***NEVER use a hammer*** Also *Note the input housing MUST be supported from the inside at the lube seal area to the press bed, failure to properly support the input housing will cause the drum to crack and void any and all warranty provided (cracks sometimes not visible to the naked eye) Apply loctite at splines as well as around the machined area of the shaft that seals into the input housing. Stop once the shaft stops- do not force beyond its stopping point. *Note you MUST blow out the input shaft feed oil passages, including lube passages thoroughly with air – as SOON as your done pressing. Failure to blow them out will result in hardened loctite or aluminum shavings in the ports possibly restricting oil flow leading to failure. Recommend using a new 3-4 apply piston and Transgo high rpm spring kit. Assemble all internals just as oem, including input sprag assembly, overun and forward clutch packs.
Step 3
Install bottom pressure plate, then starting with a friction and ending with a steel plate, install the frictions and steels (8) of each.
*Note, make sure your clutch stack ends in a STEEL. We understand this is UNlike most transmissions however this is MANDATORY. You do NOT run a friction against the billet end cap. The final steel puts the rotational forces into the input housing and not the cap. The billet cap takes strictly upward forces.
Step 4
With clean oil on the threads, GENTLY start the billet cap onto the input housing. It usually starts best by turning slightly counter clockwise slightly to aide in lineup. *** DO NOT FORCE THE THREADS *** they are shipped pre installed with oil and glide freely. Any nicks in the threads must be deburred before assembly.
Run the cap down until the top of the drum and the underside of the cap start to touch and line up the 5 drum dimples to the end caps 5 holes. Put a small drop of loctite onto the supplied 5 Allen set screws and install them staggering them while running them up snug. Once snug make a final pass tightening them all to 35 inch pounds of torque.
*Note if you’ve tightened and removed the set screws at any point, before reassembly take a fine file lightly across the top of the drum to clean off any high spots or burrs. Clean off any burrs on underside of cap as well. Wash and oil before any assembly.
*** IMPORTANT NOTE *** BEAST SUNSHELL - CANNOT be used with the 4L79 or 4L78 drums
4L78 Input housing / Drum assembly instructions
*Any questions call (219) 577-6301
Step 1
Clean input housing and Billet cap with care, the threads on both the input housing / drum and billet cap are very fine and aluminum. We recommend washing and immediately applying new Atf to the threads and performing all press work with the cap on the drum. Atf has proven best in making the threads glide with ease with no galling, sticking or any other adverse effects. *Note the use of heat from a small propane torch will make the aluminum expand and contract very quickly and very easily. If you have any issues we recommend using heat during assembly or disassembly.
Step 2
*Note that the input housing and the input shaft have a "blind spline" used for lineup that both must be lined up before pressing. ***NEVER use a hammer*** Also *Note the input housing MUST be supported from the inside at the lube seal area to the press bed, failure to properly support the input housing will cause the drum to crack and void any and all warranty provided (cracks sometimes not visible to the naked eye) Apply loctite at splines as well as around the machined area of the shaft that seals into the input housing. Stop once the shaft stops- do not force beyond its stopping point. *Note you MUST blow out the input shaft feed oil passages, including lube passages thoroughly with air - as SOON as your done pressing. Failure to blow them out will result in hardened loctite or aluminum shavings in the ports possibly restricting oil flow leading to failure. Assemble all internals just as oem including input sprag assembly, overun and forward clutch packs.
Step 3
Install bottom pressure plate, then your entire 3-4 clutch pack starting with a friction and ending with a steel plate
*Note- make sure your clutch stack ends in a STEEL. We understand this is UNlike most transmissions however this is MANDATORY. You do NOT run a friction against the billet end cap. The final steel puts the rotational forces into the input housing and not the cap. The billet cap takes strictly upward forces. Clutch clearance can be adjusted by using any stock style steels or frictions of different thicknesses.
Step 4
With clean oil on the threads, GENTLY start the billet cap onto the input housing. It usually starts best by turning slightly counter clockwise to aide in lineup. *** DO NOT FORCE THE THREADS *** they are shipped pre installed with oil and glide freely. With clutch pack installed, install the 10 new springs provided into the Oem retainers. Install retainer UPSIDE DOWN make sure the springs are facing the inside of the drum and the metal portion facing outward. Run the cap down until the top of the drum and the underside of the cap start to touch and line up the 5 drum dimples to the end caps 5 holes perfectly. Put a small drop of loctite onto the supplied 5 Allen set screws and install them staggering them while running them up snug. Once snug make a final pass tightening them all to 35 inch pounds of torque.
*Note if you've tightened and removed the set screws at any point, before reassembly take a fine file lightly across the top of the drum to clean off any high spots or burrs. Clean off any burrs on underside of cap as well, wash and oil before any assembly.
*** IMPORTANT NOTE *** BEAST sunshell CANNOT be used with 4L78 or 4L79 drums ***
4L79 or its counterparts are not liable for any damages or injuries occurring or incurred because of, or as a result of any of the products or recommendations listed on this site, as they are intended for racing / heavy duty applications. End user and or purchaser accepts and bares any and all responsibilities and liabilities.
-If an input shaft and sleeve kit was purchased and installed by us at the time of sale, 4L79, 4L78 and 4L75 input housings will have a 1 year warranty from the date of purchase to the original purchaser – on the housing and billet CAP with the exception of any assembly or disassembly issues as listed below. It does not cover the clutch pack or pressure plate.
-All warranties must be accompanied by original receipt. Warranty does not cover any breakage or damages to the spline area due to overpowering or incorrect pressing of input shaft into the housing or damages to the threads of the input housing or cap due to incorrect assembly or disassembly procedures (galled, smashed, cross threaded etc) Warranty does not include any shipping or damages resulting from a failure. All sales are final with no returns. All input housing kits are inspected and verified before being packaged and leaving our facility.
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