I have a 1991 Dodge Ram 150 whenever I first start it up it drives great but when the transmission warms up the transmission starts slipping

Rian Peters

• 121 Answers
• Posted on Aug 10, 2008

SOURCE: 1986 dodge ram 150 tranny problem

Sorry this is not an easy fix the clutch packs in the transmission are slipping, usually caused by wear, but the hydraulic pump is probably getting week. As the oil warms up the oil gets thinner and the hydraulic pressure decreases. Times for a overhaul of the transmission, and if the torque converter can not be flushed a new torque converter is recommended. You may get lucky buy changing the fluid several times, but if the transmission is 22 years old it may not help.

SOURCE: Automatic Transmission Problems

1. Check the transmission fluid level, if it's low, you have a leak & Look for fluids that have leaked on the ground below the transmission. Check the transmission case as well. Fluid can leak from seals, gaskets, fluid cooler and lines. Pinpoint the exact source of the leak to make proper repairs.
2. Place a few drops of transmission fluid on a white paper towel. Red or light brown fluid that spreads easily over the towel is in good condition. Dark brown or black fluid that is gooey or thick fluid needs replacing to allow proper pressure and lubrication within the transmission.
3. Replace the fluid filter to ensure it's in good working order. Check the old filter for metal shavings, which are a sign of wear and require a fluid flush.
4. Look at your check engine light to verify it has not come on. If the check engine is on, take the car to a mechanic who can pull the code and pinpoint the problem. Electronic transmissions can detect even small faults in operation, and you may want to drive the car to verify that the problem was not a one-time or erroneous error.
5. Seek the assistance of a professional if the car is no longer going into gear, slipping out of gear while driving or a substantial amount of fluid is leaking. Fixing a transmission problem on your car early can save you money and help keep you on the road for a long time to come.

SOURCE: 1991 Buick Park Avenue transmission slips until warmed up

Have u tried a tranny sevice? The fluid and seal r bad it is exspanind as it heats! Try a tranny service i reccomend every 60,000 miles!

SOURCE: I have a 1999 dodge ram with an automatic

Have you replaced the transmission filter and fluid yet,
if your transmission works ok until it heats up,your transmission external cooler may be plugging up getting the transmission fluid to hot and not cooling it at all.It is located in front of your A/C and radiator.you can replace it with an after market one or have it flushed.
and you might want to put in an additive for the transmission made my Lucas.

SOURCE: dodge 1991 d 150 moter will crank but not satart

I had the same problem with my 91 dodge truck. I checked everything and found the problem to be in the fuel pump relay, it was not making good conection, spayed some WD40 on the conecters and have not had any problems.