Jeep Wrangler JK/JL Automatic Transmission Guide by Year

Jeep Wrangler automatic transmissions vary widely between JK (2007-2018) and JL (2018+) generations. Heres what is in each and what to expect for service and rebuild.

2007-2011 Wrangler JK (42RLE):

Specs:

  • 4-speed automatic
  • Behind 3.8L V6
  • ~320 ft-lb stock rating
  • Mopar HD-derived design

    • 2012-2018 Wrangler JK (W5A580):

    Specs:

  • 5-speed Mercedes-Benz NAG1 (also W5A580)
  • Behind 3.6L Pentastar V6
  • ~290 ft-lb stock rating
  • European-style trans

    • 2018+ Wrangler JL (850RE):

    Specs:

  • 8-speed automatic (ZF 8HP70-derived)
  • Behind 3.6L Pentastar V6, 2.0L Turbo, 3.0L EcoDiesel
  • ~400-450 ft-lb stock rating
  • Modern ZF design

    • How to ID your Wrangler trans

    By year:

  • 2007-2011: 42RLE
  • 2012-2018: NAG1/W5A580
  • 2018+: 850RE

    • By shifter:

  • 42RLE: floor shifter with PRNDL
  • NAG1: floor shifter with manual mode
  • 850RE: rotary dial shifter (some) or traditional

    • Common 42RLE failures

    Most common at 100k-180k miles:

  • Solenoid pack failure
  • 2-3 shift solenoid (P0731 / P0732)
  • OD wear (P0735 / P0700)
  • TCC clutch shudder

    • Cost to repair:

  • Solenoid pack: $200-$400 part + $200-$400 labor
  • Full rebuild: $2,000-$3,200

    • Common NAG1/W5A580 failures

    Most common at 80k-150k miles:

  • Conductor plate failure (Mercedes design weakness)
  • Pilot bushing wear
  • 3rd gear clutch wear (worse on tuned)
  • 13-pin connector seal failure

    • Cost to repair:

  • Conductor plate: $400-$700 part + $500-$800 labor
  • Full rebuild: $2,800-$4,500
  • Mercedes parts can be expensive

    • Common 850RE failures

    Most common at 50k-120k miles:

  • Mechatronic failure (ZF unit issue)
  • Harsh shifts when tuned
  • Fluid sensitivity
  • Stop/start system issues

    • Cost to repair:

  • Mechatronic: $1,000-$2,000 unit + labor
  • Full rebuild: $3,500-$5,500

    • Off-road specific issues

    All Wrangler trans suffer from:

  • Sustained low gear stress (rock crawling)
  • Crawl ratio multiplied through 4Lo
  • Heat from slow technical driving
  • Trans temp gauge install recommended

    • Tire upgrade impact:

  • 33+ inch tires increase load on stock gears
  • Re-gear axles required to protect trans
  • Without re-gear: trans wears 30-50% faster

    • Fluid spec

    42RLE:

  • ATF+4 ONLY (Mopar)
  • NOT Dexron
  • 10 quarts

    • NAG1/W5A580:

  • Mopar ATF+4 or Mercedes 236.14
  • 9 quarts
  • Specific spec critical

    • 850RE:

  • Mopar ZF ATF (specific Jeep PN)
  • NOT regular ATF+4
  • 9 quarts

    • Service intervals

    Daily driver:

  • 42RLE: 50k miles
  • NAG1: 60k miles
  • 850RE: 60k miles

    • Off-road/heavy use:

  • All trans: 30k miles
  • Inspect fluid after every major trail run

    • Tuning limits

    42RLE:

  • Stock 3.8L: no significant tuning
  • HD limit: ~400 ft-lb

    • NAG1/W5A580:

  • Pentastar tune: ~325 ft-lb (stock trans marginal)
  • LS swap: requires HD upgrade or trans swap

    • 850RE:

  • EcoDiesel tune: ~480 ft-lb (stock OK)
  • LS swap with 850RE: requires custom TCM work

    • LS swap considerations

    Common Jeep LS swap:

  • Replaces 3.8L or 3.6L with 5.3L or 6.0L LS
  • Trans options: 4L60E, 4L65E, or 4L80E with adapter
  • NOT typically the OEM Jeep trans

    • Trans recommendations:

  • Light LS swap: 4L60E (cost-effective)
  • HD LS swap: 4L80E (strength)
  • Read our 4L60E to 4L80E swap

    • Rebuild costs

    42RLE rebuild:

  • Stock: $1,800-$2,800
  • HD: $2,800-$4,000

    • NAG1/W5A580 rebuild:

  • Stock: $2,500-$3,800
  • HD: $3,800-$5,500
  • Mercedes parts expensive

    • 850RE rebuild:

  • Stock: $3,500-$5,000
  • HD: $5,000-$7,500
  • Limited shop knowledge

    • Pre-purchase used Wrangler check

    Drive test:

  • All gear engagement
  • TCC engagement smoothness
  • Cold-start shift behavior
  • 4WD low gear stress test

    • Red flags:

  • Burnt fluid smell
  • Conductor plate codes (NAG1)
  • Mechatronic codes (850RE)
  • Tuned without records
  • Big tires without re-gear

    • Off-road durability tips

    For all Wrangler trans:

  • Aux trans cooler ($150-$300)
  • Trans temp gauge install
  • Frequent fluid service (every 30k off-road)
  • Skip plate to protect pan
  • Re-gear if running 33+ tires

    • Cost summary by trans

    42RLE total cost over 200k miles:

  • Service every 30k: $250 x 6 = $1,500
  • Rebuild at 150k: $2,500
  • Total: ~$4,000

    • NAG1 total cost over 200k miles:

  • Service every 30k: $300 x 6 = $1,800
  • Rebuild at 150k: $3,500
  • Total: ~$5,300

    • 850RE total cost over 200k miles:

  • Service every 40k: $400 x 5 = $2,000
  • Rebuild at 200k: $4,500 (if needed)
  • Total: ~$6,500

    • Need Wrangler transmission rebuild parts? Visit our main catalog. 42RLE, NAG1, 850RE master rebuild kits. Free shipping over $70.

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