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The Allison 1000 is the reason a Duramax truck holds value. It is a commercial-derived 5-speed (2001–2005) and 6-speed (2006 and up) planetary automatic that will take far more abuse than the 4L80E it replaced. But nothing is immortal behind a tuned LB7 pulling a gooseneck, and when the 1000 finally lets go, the parts list is longer and more specific than most people expect.
This page is the actual bill of materials. Not a generic "rebuild kit" pitch — the individual pieces, what fails first, what you can reuse, and what a shop charges to put it all together.
Know Which Allison 1000 You Have Before You Order
Ordering the wrong generation of parts is the single most common mistake on this rebuild. There are four practical variants:
- 2001–2005, 5-speed. Behind LB7 and early LLY. Fewer clutch plates in some packs, different valve body calibration.
- 2006–2007, 6-speed. The sixth gear arrives, the C2 and C3 packs get more capacity, and the internal wiring harness changes.
- 2008–2010. Continued refinement, still the same basic architecture.
- 2011 and up, behind LML / L5P. Higher-capacity clutch counts, updated converters, and the strongest version of the case.
Buy your master kit by year and engine code, not by "Allison 1000." Reputable kit suppliers will ask you for the year and the RPO. If they do not ask, buy somewhere else.
The Core Parts List
Master overhaul kit (the foundation)
A proper master kit for the 1000 includes the full friction set for C1 through C5, steels, the complete gasket and seal set, o-rings, sealing rings, thrust washers, the bushing set, and both filters. Kits from Transtar, ATP, and the OEM-supplier houses run $580 to $950 depending on friction material. Budget "banner kits" that only include seals and gaskets are $190 to $320 — useful only if you are reusing frictions, which on a failed unit you almost never should.
Frictions and steels
This is where the money decision gets made. Three tiers:
- OE-equivalent paper frictions. Fine for a stock truck that tows occasionally. Included in most master kits.
- Alto Red Eagle / high-energy frictions. Roughly $180–$320 over a stock kit. Meaningful heat capacity gain. This is the right choice for anything towing regularly.
- Raybestos GPZ / carbon-composite. $350–$600 over stock. For tuned trucks making real power. Overkill on an untuned LBZ.
Buy new steels, not reused ones. Steels that have been heat-cycled look flat and are not; a reused steel with a heat spot will cook a new friction in a season. Steels are cheap. Comebacks are not.
Filters
The 1000 uses an internal (suction/main) filter inside the pan plus a spin-on external filter mounted on the case. Both get replaced. A complete Allison filter kit including both filters and the pan gasket runs $55–$110. Do not buy the cheapest listing on a marketplace — counterfeit Allison filters are a real problem and a collapsed filter media takes out a fresh rebuild.
Allison 1000 filter kits
Torque converter
Never reuse the converter on a failed Allison. When clutch material circulates, it packs into the converter and comes back out into your new build within a thousand miles. Options:
- Reman stock converter: $340–$600 with core.
- Single-disc heavy-duty: $600–$900. Worth it on any truck that tows.
- Triple-disc billet: $900–$1,600. For tuned trucks and heavy commercial pulling.
Full sizing and pricing detail is in our Allison 1000 torque converter replacement cost guide and our comparison of the best Allison 1000 converters for towing.
Valve body and solenoids
If the failure came with shift complaints or a solenoid code, the valve body gets addressed during the rebuild, not after it goes back in the truck. Shift solenoids run $80–$190 each; a complete solenoid set is $380–$700. Sonnax makes bore repair kits for the pressure regulator and TCC circuits that are worth doing on any unit past 150k miles. A TransGo-style shift kit for firmer, faster apply is $130–$210 and is the cheapest real durability upgrade on the whole list.
Hard parts you should inspect, not automatically buy
- C1 and C2 hub splines — check for rounding.
- P1 / P2 / P3 planetary carriers — look for pinion needle bearing failure and blued gear teeth. A carrier is $250–$550.
- Main shaft and turbine shaft — twisted splines on a tuned truck are common.
- Pump — check gear-to-body clearance. A pump assembly is $350–$700.
- Internal wiring harness and speed sensors — $120–$260. Cheap insurance while it is apart.
2026 Parts and Labor Pricing
| Item | Parts Cost | Notes |
|---|---|---|
| Master overhaul kit (frictions, steels, seals, filters) | $580 – $950 | Order by year and engine RPO |
| Seal / gasket banner kit only | $190 – $320 | Reseal jobs only |
| High-energy friction upgrade | +$180 – $600 | Alto Red Eagle to GPZ tier |
| Internal + external filter kit | $55 – $110 | Buy genuine; counterfeits exist |
| Torque converter | $340 – $1,600 | Stock reman to triple-disc billet |
| Complete solenoid set | $380 – $700 | Individual solenoids $80 – $190 |
| Shift kit / valve body upgrade | $130 – $210 | Best value durability item |
| Planetary carrier (each, if damaged) | $250 – $550 | Inspect, do not auto-replace |
| Pump assembly | $350 – $700 | Check clearances first |
| TES-certified fluid, full fill | $180 – $340 | 13–15 quarts typical service fill |
| Shop labor, R&R plus rebuild | 14 – 20 hrs | $1,800 – $3,200 at $130–$165/hr |
| Typical complete shop rebuild total | $4,200 – $7,500 | Higher with billet converter and upgrades |
| DIY parts-only total, stock rebuild | $1,400 – $2,600 | Assumes no damaged hard parts |
For the full labor-side breakdown and how shop quotes differ regionally, see our Allison 1000 rebuild cost guide. If you would rather buy a complete kit than assemble a list, we cover suppliers in where to buy an Allison 1000 rebuild kit.
What Actually Fails on These
Knowing the failure pattern tells you which parts to order heavy and which to order stock.
C3 clutch pack
The most common failure on towed and tuned trucks. Symptom is a slip or flare on the 3-4 or 4-5 shift under load, sometimes with a code for gear ratio error. If the truck came in with that complaint, order the upgraded frictions.
C2 clutch pack
Second most common. Shows as reverse and a forward gear both degraded, because C2 is shared.
Torque converter clutch
Shudder at 45–65 mph under light load, worse with a trailer. On the Allison this is frequently the converter clutch damper rather than a valve body problem. Our Allison 1000 shudder diagnosis separates the two.
Solenoid and pressure control faults
P0700 stored at the ECM with the real code in the TCM. If you are chasing this before deciding on a rebuild, our P0700 on an Allison 1000 guide walks the diagnostic order.
Overheating from a plugged cooler
This one destroys fresh rebuilds. When the original transmission failed, it pushed debris into the cooler and lines. Flush the cooler with a pulse flusher or replace it. A $180 cooler is cheaper than doing the whole job twice.
Fluid: This Is Not Optional
The Allison 1000 wants a TES-certified fluid. Dexron-spec ATF is not an approved substitute regardless of what the bottle claims. The certification generations matter and are not interchangeable in both directions — we break the difference down in TES-295 vs TES-668. Our fluid picks for a Duramax application are in best transmission fluid for the Allison 1000.
Service fill after a rebuild is typically 13–15 quarts with a deep pan and cooler drained; dry fill including converter is higher. Fill, run through the gears, check level hot at idle, and top as needed.
Tools You Will Need on the Bench
- Clutch clearance gauge set or a good dial indicator with a magnetic base. Pack clearance is the single most important measurement in this build.
- Snap ring pliers, internal and external, in a size range that actually fits heavy commercial rings.
- A transmission jack rated for at least 1 ton. The Allison with converter is over 400 pounds wet.
- Inch-pound and foot-pound torque wrenches.
- Parts washer or a solvent tank. You cannot build a clean transmission on a dirty bench.
Clutch clearance gauges and dial indicators
Heavy-duty snap ring plier sets
1-ton transmission jacks
Need Parts? Ships Same-Day
Master kits, frictions, steels, filters, solenoids, and converters for the Allison 1000 and the rest of the bench. Same-day ship before 2pm Eastern.
Shop Gearbox Insider →FAQ
Can I rebuild an Allison 1000 in my garage?
Yes, if you can measure. It is a clean, logical planetary build with no unusual special tools beyond clutch clearance measurement. The hard part is discipline: correct clearances, new steels, clean assembly, and flushing the cooler.
Do I need to reprogram anything after a rebuild?
The transmission control module needs an adaptive relearn so it can re-learn clutch fill times. Most units will do this over 50–100 miles of varied driving, but a scan tool reset gets you there faster and avoids a week of odd shifts.
Is a rebuild worth it versus a reman unit?
If the case, carriers, and shafts are good, rebuilding is $1,500–$2,500 cheaper than a comparable reman. If you find a cracked case or twisted shafts, a reman with a warranty often wins.
What mileage do these usually need a rebuild?
Stock and serviced on schedule, 250,000 miles and up is normal. Tuned and towing heavy without a fluid interval, some let go before 120,000. Fluid and cooling do more for lifespan than any single part on this list.
Should I upgrade the clutch counts while I am in there?
On a stock truck, no. On a tuned truck, adding capacity to C2 and C3 where the year allows is the highest-return upgrade you can make during the build, because getting back in there later costs another 14 hours of labor.