The 97 Jeep Grand Cherokee transmission is a robust 42RE four-speed automatic that benefits from regular fluid changes. If you own this classic SUV, you know it’s built to last, but the transmission needs attention to keep it shifting smoothly. This guide covers everything you need to know about maintaining, troubleshooting, and repairing the 97 Jeep Grand Cherokee transmission.
Let’s start with the basics. The 42RE transmission in your 1997 Grand Cherokee is a workhorse. It handles the 4.0L inline-six or the 5.2L V8 engine well. But like any older part, it has weak points.
97 Jeep Grand Cherokee Transmission Overview
The 42RE is a four-speed automatic with overdrive. It uses a hydraulic control system with electronic shift solenoids. This design gives you smooth shifts when everything works right.
Common issues include slipping between gears, delayed engagement, and hard shifts. These problems often trace back to low fluid, worn solenoids, or a clogged filter. Regular maintenance prevents most of these headaches.
Transmission Fluid And Filter Changes
Change the fluid and filter every 30,000 miles. Use only ATF+4 fluid. This is critical for the 97 Jeep Grand Cherokee transmission. Wrong fluid causes slipping and overheating.
- Drain the pan and replace the filter
- Refill with ATF+4 until it runs clear
- Check fluid level with engine running and warm
You can do this yourself with basic tools. A drain pan, a new filter kit, and about 5 quarts of fluid are all you need. It takes about an hour.
Common Transmission Problems
Owners report several recurring issues. Here’s what to watch for:
- Slipping when accelerating
- Hard shifts from first to second
- No reverse gear
- Overdrive not engaging
- Transmission overheating
Many of these stem from the transmission control module (TCM) or solenoids. The TCM on the 97 model can fail, causing erratic shifting. Replacing it is a straightforward fix.
Diagnosing Solenoid Issues
The shift solenoids inside the valve body wear out. You’ll notice harsh shifts or no shift at all. Test them with a multimeter. Resistance should be between 11 and 15 ohms. Replace any that are out of spec.
Another common cause is a bad throttle position sensor (TPS). The TPS tells the transmission when to shift. A faulty one causes late or early shifts. Scan for codes to confirm.
Rebuilding The 97 Jeep Grand Cherokee Transmission
If your transmission is slipping badly or has no forward gears, a rebuild might be needed. This is a big job, but doable at home with the right tools.
Start by removing the transmission from the vehicle. You’ll need a transmission jack, socket set, and torque wrench. Label all bolts and hoses as you go.
- Disconnect the battery and drain the fluid
- Remove the driveshaft and transfer case
- Unbolt the torque converter from the flexplate
- Lower the transmission carefully
Once it’s out, disassemble the case. Inspect all clutches, bands, and seals. Replace any worn parts. The 42RE uses a band adjustment for the front and rear servos. Set them to spec during reassembly.
Parts You Will Need
A rebuild kit costs about $200. It includes gaskets, seals, clutches, and bands. You might also need a new torque converter if it’s damaged. Expect to spend $400 to $600 total for parts.
- Master rebuild kit
- Torque converter
- Filter and gasket
- ATF+4 fluid (10-12 quarts)
- Band adjustment tool
Take your time with the rebuild. Rushing leads to mistakes. Follow a factory service manual for torque specs and clearances.
Band Adjustment Procedure
The front and rear bands need adjustment after a rebuild. Here’s how:
- Loosen the locknut on the band adjuster
- Tighten the adjuster screw to 72 in-lbs
- Back it off exactly 2 turns for the front band
- Back it off 2.5 turns for the rear band
- Tighten the locknut to 35 ft-lbs
This ensures proper clamping force. Too tight and the band wears fast. Too loose and it slips.
Transmission Cooling System
Overheating kills the 97 Jeep Grand Cherokee transmission fast. The stock cooler in the radiator can fail, mixing coolant and fluid. This causes catastrophic damage.
Install an auxiliary transmission cooler. It adds capacity and keeps fluid temps down. Mount it in front of the radiator or A/C condenser.
- Use a cooler rated for towing
- Route hoses away from exhaust
- Add a temperature gauge to monitor
Ideal operating temp is 160-200°F. Above 220°F, fluid degrades quickly. A cooler extends transmission life significantly.
Flushing The System
Every 60,000 miles, flush the entire system. This removes old fluid from the torque converter and lines. Use a flush machine or do it manually by disconnecting the cooler line.
Run the engine until fresh fluid comes out. Then refill and check level. This keeps the 97 Jeep Grand Cherokee transmission running smoothly for years.
Electronic Control Module (TCM) Issues
The TCM on the 97 model is prone to failure. Symptoms include no shift, limp mode, or erratic shifting. You can test it by swapping with a known good unit.
Replacement TCMs are available new or refurbished. They cost around $150 to $300. Install it under the dash near the steering column.
Sometimes the issue is just a bad ground wire. Check the ground connections at the battery and chassis. Clean them with a wire brush and apply dielectric grease.
Scanning For Codes
Use an OBD-II scanner to read transmission codes. Common ones include:
- P0700 – Transmission control system fault
- P0740 – Torque converter clutch circuit
- P0750 – Shift solenoid A malfunction
- P1765 – Transmission 12-volt supply relay
Address these codes before replacing parts. A simple relay swap might fix the problem.
Upgrading The 97 Jeep Grand Cherokee Transmission
If you plan to tow or off-road, consider upgrades. A shift kit improves shift firmness and reduces slippage. Install it in the valve body.
Heavy-duty torque converters with higher stall speeds help with power delivery. They also reduce heat buildup. Pair with a larger cooler for best results.
Some owners swap in a stronger transmission from a later model. The 42RE can be upgraded with parts from the 46RE. Check compatibility before buying.
Cost Of Repairs
Here’s a rough breakdown of common costs:
- Fluid and filter change: $50-$100
- Solenoid replacement: $100-$200
- TCM replacement: $150-$300
- Full rebuild: $1,500-$2,500
- Auxiliary cooler: $50-$150
Shop around for parts. Online retailers often have better prices than local stores. But always use quality components.
Frequently Asked Questions
What Type Of Fluid Does A 97 Jeep Grand Cherokee Transmission Use?
Use ATF+4 fluid. Do not use Dexron or Mercon. Wrong fluid causes slipping and damage.
How Do I Check The Transmission Fluid On A 1997 Grand Cherokee?
Warm up the engine, park on level ground, and leave it running. Pull the dipstick, wipe it, reinsert, and check. Fluid should be pink and between the marks.
Why Is My 97 Jeep Grand Cherokee Transmission Slipping?
Low fluid, worn clutches, or a bad solenoid are common causes. Check fluid level first. If full, scan for codes.
Can I Rebuild A 97 Jeep Grand Cherokee Transmission Myself?
Yes, if you have mechanical experience and a service manual. It’s a complex job but doable at home. Expect to spend a weekend on it.
How Long Does A 97 Jeep Grand Cherokee Transmission Last?
With regular maintenance, 150,000 to 200,000 miles. Neglect reduces that to 100,000 or less.
Final Maintenance Tips
Keep up with fluid changes. Use only ATF+4. Check for leaks regularly. The 97 Jeep Grand Cherokee transmission is durable if you treat it right.
Listen for unusual noises. A whining or grinding sound means trouble. Address issues early to avoid costly repairs.
If you tow, install a cooler and change fluid more often. Every 20,000 miles is a good rule. This keeps the transmission cool and happy.
Your 97 Jeep Grand Cherokee transmission can last a long time. Just give it the care it needs. Regular maintenance, quality parts, and prompt repairs make all the difference.
One last thing: always warm up the transmission before driving hard. Cold fluid is thick and doesn’t lubricate well. Let it idle for a minute before moving.
That covers everything you need to know. Keep your 97 Jeep Grand Cherokee transmission in top shape, and it will serve you well for many more miles.