The Jeep Grand Cherokee and Cherokee run several different transmission configurations depending on year and trim — the 45RFE and 545RFE in older applications, the NAG1 (722.6) in the V8 and diesel trims, and the ZF 8HP in newer Grand Cherokees with the 5.7L Hemi and 3.0L EcoDiesel. Each has its own common failure codes, and knowing what each code means before you walk into a shop is genuinely valuable — it prevents misdiagnosis and protects your wallet. P0740/P0741 — TCC circuit/performance. Almost always fluid-related in the 45RFE. ATF+4 drain-and-fill first. P0745 — Pressure control solenoid performance. The governor pressure solenoid on the 45RFE is a common failure. If P0745 persists after a fresh ATF+4 service, the solenoid is the likely culprit — it's a serviceable part accessible from the valve body. P0750/P0755 — Shift solenoid A/B performance. Check fluid first, then wiring harness at the transmission connector, then solenoid. P0700 — Generic TCM fault. Pull Chrysler-enhanced sub-codes with a capable scanner — P0700 alone tells you nothing actionable.
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Mopar ATF+4
Search AmazonRequired fluid for 45RFE, 545RFE, and NAG1 in Jeep Grand Cherokee and Cherokee applications. The first diagnostic step for any of the codes listed above is verifying ATF+4 spec and condition. Pick up 6 quarts for a drain-and-fill service before any parts are ordered.
Check Price on AmazonBlueDriver Bluetooth OBD2 Scanner
$89.95Reads Chrysler-enhanced codes on all Grand Cherokee and Cherokee transmission applications — 45RFE, NAG1, and ZF 8HP. Pulls the sub-codes under P0700 that tell you what's actually wrong, plus live data including governor pressure duty cycle on the 45RFE and TFT on all units. The tool that makes all of the above codes actionable rather than just alarming.
Check Price on AmazonLucas Oil Transmission Fix
$14.87Useful on 45RFE and NAG1 applications showing P0745 or P0730 where fluid service is the first step. Helps recondition governor pressure solenoid seals and valve body hydraulic circuits on Jeep transmissions that have been running degraded ATF+4. Add to a fresh fluid service before any solenoid replacement is authorized.
Check Price on Amazon