62TE Towing Upgrades and Cooling

The 62TE was never sold as a tow rig transmission. It is a 41TE four-speed with an underdrive compounder bolted to the back, packed into a minivan, a Journey or a midsize sedan. Yet plenty of these units spend their summers pulling pop-up campers, jon boats and utility trailers, and the ones that come back to the shop with a burnt smell and a flare on the 2-3 almost always have the same story: a long grade, a hot day, a full van and a trailer that was near or over what the vehicle is rated for.

The good news is that the 62TE tolerates towing inside its rating when the heat is managed. Nearly every towing failure we see starts as a temperature problem long before it becomes a clutch problem. This guide covers what Chrysler actually rates these vehicles to pull, where the heat comes from inside the unit, the one valve in the cooler circuit that quietly kills rebuilds, and the upgrades that actually lower fluid temperature: driving technique, an auxiliary cooler, a tighter fluid schedule and a proper cooler flush. The specs come from Chrysler's 62TE service information, the Grand Caravan owner's manual, ATRA's 62TE technical update, a Chrysler/FCA bulletin and Sonnax.

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What Chrysler Rates a 62TE Vehicle to Tow

Start with the number, because no cooler upgrade makes up for an overloaded trailer. The 2019 Dodge Grand Caravan owner's manual lists one drivetrain, the 3.6L with the automatic (the 62TE), and three trailer ratings depending on how many people are in the van:

• Up to 2 persons and luggage: 3,600 lb maximum gross trailer weight, 360 lb maximum tongue weight
• 3 to 5 persons and luggage: 3,450 lb trailer, 345 lb tongue
• 6 to 7 persons and luggage: 3,000 lb trailer, 300 lb tongue

All three share an 8,750 lb gross combined weight rating and a 40 square foot maximum trailer frontal area. That frontal area limit matters more than people think: a boxy camper pushing a wall of air at 65 mph loads the converter and the clutches far harder than a low boat of the same weight. The same manual says trailer brakes are recommended over 1,000 lb and required over 2,000 lb, and it tells you to load 60 percent of the trailer's weight toward the front so about 10 percent of the gross trailer weight sits on the hitch.

Older model years, the Journey and the sedans carry different ratings, so pull the owner's manual for the exact vehicle. The point is that a family of six in a Grand Caravan is already down 600 lb of trailer capacity from the brochure number, and a transmission shop sees the result of that math every summer.

Where Towing Heat Comes From in a 62TE

Converter slip

Most of the heat a towing 62TE makes is generated in the torque converter, not in the clutch packs. Chrysler's service information says the converter clutch provides reduced engine speed and greater fuel economy when engaged, and that clutch engagement also provides reduced transmission fluid temperatures. The catch is when it can engage. Per the same document, the PCM will not apply the converter clutch in the lower gears because it needs the converter's torque multiplication for acceleration; the clutch engages in third gear, at approximately 35 mph with light throttle, and the inputs are coolant temperature, vehicle speed and throttle position.

With a trailer on, throttle position is high and the PCM unlocks the converter every time it downshifts or the driver leans on it. An unlocked converter under load is a fluid shear pump that turns horsepower straight into heat. ATRA also describes the 62TE converter as a "squished design," shortened to fit the packaging, which leaves less fluid volume in the converter to absorb that heat.

Gear hunting

The 62TE has seven forward ratios and a shift schedule tuned for fuel economy. On a grade with a trailer it tends to cycle between 6th, 5th and 4th, and every one of those shifts means clutch slip and, usually, a converter unlock. Hunting is the single biggest heat multiplier we see on towing units, and it is also the easiest to stop (more on that below).

The cooler circuit

Hot converter outflow is supposed to travel through the cooler and come back to feed lube. If anything reduces that flow, the heat has nowhere to go. That brings us to the part that deserves the most attention on any 62TE that tows.

The Cooler Bypass Valve: The Part That Kills Towing Rebuilds

The 62TE has a cooler bypass valve that lives in the case behind the oil pump. Sonnax, explaining cooler control valves across OEM designs, notes that Chrysler's 41TE and 62TE use pressure-sensitive relief valves mounted behind the pump, as opposed to the wax-element thermal valves used in units like the RFE family. A pressure relief valve in this position is meant to open when the cooler circuit is restricted, so the converter is not dead-headed. The problem, per Sonnax, is that weak springs or a contaminated seat let a pressure relief valve stay open. When that happens, converter outflow skips the cooler and the unit runs hot even with a perfectly good radiator.

Chrysler's service information is blunt about this valve: if transaxle failure has occurred, the cooler bypass valve must be replaced, and it says not to reuse or attempt to clean it. It installs with the O-ring end toward the rear of the case. ATRA's 62TE update calls the cooler bypass valve "a high risk area" and recommends a new valve any time the transmission is repaired, not just after a failure.

Here is why that matters for towing. A unit that has already slipped a clutch has sent friction and metal through the converter and out to the cooler. Some of that debris lodges in the bypass valve. A rebuilt unit that goes back in with the old valve can bypass the cooler from day one, and the first long tow kills it. If you are building a 62TE for a customer who tows, the valve is not optional.

How to Watch Temperature

You cannot manage heat you are not measuring. The 62TE solenoid and pressure switch assembly carries a transmission temperature sensor (Transmission Digest lists it alongside the six shift solenoids, the line pressure solenoid and five pressure switches), so the fluid temperature is available in a few places:

• The warning light. The Grand Caravan manual describes a Transmission Temperature Warning Light, on equipped vans, that comes on with high fluid temperature and names trailer towing as a typical cause. The instruction is to stop, run the engine at idle or slightly faster in PARK or NEUTRAL until the light goes out, then continue. The manual warns that driving on with the light on can boil the fluid over onto hot engine or exhaust parts and cause a fire, and will eventually cause severe transmission damage.
• The cluster display. The same manual lists a Transmission Temperature readout in the instrument cluster display on equipped vans. If yours has it, keep it on the screen when towing.
• The scan tool. Chrysler's fluid level procedure reads Transmission Fluid Temperature (TFT) on a scan tool and gives 82 C (180 F) as normal operating temperature. A cheap Bluetooth reader with a Chrysler-capable app will show TFT live on a tow.

Treat 180 F as your baseline. If a known trip pushes the number well above that and keeps it there, the vehicle needs one of the upgrades below before the next trip, not after the light comes on.

Upgrade 1: Drive It Like a Tow Rig

This costs nothing and it does more than any bolt-on. The Grand Caravan manual says DRIVE can be used when towing, but if frequent shifting occurs, use Electronic Range Select (ERS) to choose a lower gear range. Chrysler's reasoning is the same as ours: a lower range under heavy load reduces excessive shifting and heat buildup and extends transmission life. The manual's specific advice is to pick the highest gear that holds speed without frequent downshifts, for example "4," and drop to "3" or "2" only if needed, while avoiding continuous high RPM.

Holding a gear stops the hunting, and a transmission that is not shifting can keep the converter clutch applied. For hot weather, the manual adds: in city traffic, put it in NEUTRAL at stops without raising idle, and on the highway reduce speed and temporarily turn off the air conditioning. Leave the cruise control off on hilly terrain and with heavy loads, per the same section.

Upgrade 2: Add an Auxiliary Cooler

The factory cooler on these vehicles is sized for the vehicle, not for the vehicle plus a camper. An add-on cooler is the right hardware upgrade for a 62TE that tows regularly. How we install them:

• Plumb it in series, on the return line. Fluid should leave the transmission, go through the factory cooler, then through the auxiliary cooler, then back to the case. Never bypass the factory cooler. The auxiliary cooler adds capacity; it does not replace what Chrysler designed in.
• Pick a plate-and-fin or stacked-plate core. These shed more heat per square inch than tube-and-fin at the same size. A unit rated in the low-20,000 GVW range is plenty for a minivan; bigger only slows warm-up.
• Mount it where it gets clean air. In front of the condenser, with space around it, and secured so it cannot rub through a line.
• Use proper hose and clamps. Transmission cooler hose rated to SAE J1532, not fuel or heater hose. The factory lines use quick-connect fittings; Chrysler's procedure removes them with disconnect tool 8875A, and on reinstall you should hear an audible click and then pull on the line to verify it is locked.

After installation, run the engine, confirm fluid is returning, recheck the level (the added cooler and hose hold fluid), and then check for leaks at operating temperature.

Upgrade 3: Put It on the Towing Fluid Schedule

ATF+4 is the only fluid for this unit. Chrysler's service information says to use only fluids labeled Mopar ATF+4, and the bulletin covering low fluid level lists part 05013457AA. What changes for a tow vehicle is the interval. The owner's manual is specific: if you regularly tow for more than 45 minutes of continuous operation, change the fluid and filter on the schedule for police, taxi, fleet or frequent trailer towing. Chrysler also points out that ATF+4 darkens and its odor changes with normal use, so color and smell cannot tell you when it needs changing. Go by the schedule.

The service itself, per Chrysler's 62TE procedure:

1. Drop the pan and remove the filter nuts.
2. Install the new filter and tighten the nuts to 5 N·m (40 in-lb).
3. Clean the pan and magnet, seal the pan with Mopar ATF RTV, and tighten the pan bolts to 6 N·m (50 in-lb).
4. Add four quarts of ATF+4 through the fill tube.
5. Idle at least one minute, cycle the selector through each position, and bring the level to 3 mm (1/8 in) below the lowest dipstick mark.
6. Set the final level with dipstick tool 9336A (marks every 10 mm) read against TFT on the scan tool, and recheck at 82 C (180 F).

Do not skip the final level set. FCA bulletin 21-046-15 was written because under-filled 62TE units in 2015 Grand Caravans and Town and Countrys produced harsh shifts under heavy acceleration. A low unit pulling a trailer aerates, loses apply pressure and slips, and slipping makes heat. Full specs are in our 62TE fluid type and capacity guide, and the pan and filter job is walked through in our 62TE filter and pan service guide.

Upgrade 4: After Any Failure, Clean the Whole Circuit

If a towing 62TE has already failed and is being rebuilt or replaced, the cooling system is part of the job:

• Replace the cooler bypass valve. Chrysler says replace, ATRA says replace on any repair. Do not clean it.
• Flush the cooler and lines. Debris left in the cooler is pumped straight into the new unit's lube circuit. Flush with a dedicated cooler flush, blow the lines out in both directions, and flush again until clean. If the cooler will not come clean, replace it.
• Verify flow before the vehicle leaves. With the return line routed into a container, confirm a strong, steady stream at idle. Weak flow means a restricted cooler, a kinked line or a bypass problem.
• Do the Quick Learn. Chrysler requires the TCM/PCM Quick Learn procedure after an overhaul involving clutch or seal replacement. A unit that has not relearned its clutch volumes shifts sloppily, and sloppy shifts under a trailer are slip time.

What Not to Do

• Do not tow over the rating and expect a cooler to save it. The cooler handles heat; it does nothing for clutch capacity or the underdrive compounder.
• Do not reuse the old bypass valve on a rebuild that is going back into a tow vehicle.

FAQ

How much can a Grand Caravan with the 62TE tow?

The 2019 Grand Caravan owner's manual rates the 3.6L automatic at 3,600 lb with up to two people and luggage, 3,450 lb with three to five, and 3,000 lb with six or seven, with tongue weight at 10 percent. Trailer brakes are recommended over 1,000 lb and required over 2,000 lb. Other years and models differ, so check the manual for your vehicle.

What is normal 62TE operating temperature?

Chrysler's 62TE service information gives 82 C (180 F) as normal operating temperature and uses it for the final fluid level check. When towing, watch transmission fluid temperature on the cluster display or a scan tool and treat readings that stay well above that as a sign the unit needs more cooling.

Should I add an auxiliary transmission cooler to a 62TE for towing?

Yes, if you tow regularly. Plumb a plate-and-fin or stacked-plate cooler in series on the return line after the factory cooler, use SAE J1532 transmission hose, and recheck the fluid level afterward because the cooler and hoses hold extra ATF+4. Do not bypass the factory cooler.

How often should I change 62TE fluid if I tow?

The owner's manual says that if you regularly tow for more than 45 minutes of continuous operation, change the fluid and filter on the police, taxi, fleet or frequent-towing schedule. Use ATF+4 only, and set the level with tool 9336A against fluid temperature on a scan tool.

What does the 62TE cooler bypass valve do?

It is a pressure-sensitive relief valve behind the pump that lets converter outflow bypass a restricted cooler. If it sticks open, fluid skips the cooler and the unit runs hot. Chrysler says to replace it, never clean or reuse it, after any transaxle failure, and ATRA recommends a new one on every repair.