Transmission does not engage when it's cold. Mechanic recommend flushing the transmission fluid. Is that a good idea?

The erratic jumping in and out of overdrive (O/D) on your 2006 Terrano 3GMR with a 3.2L engine could be caused by a few different issues. Here are some possible causes and fixes:

1. Faulty speed sensor: The speed sensor provides input to the transmission control module (TCM) to determine when to engage overdrive. A faulty sensor can cause the TCM to think the vehicle is going too slow or too fast for overdrive engagement. A mechanic can test the speed sensor and replace it if necessary.
2. Low transmission fluid level: Low transmission fluid level can cause the transmission to shift erratically or not engage overdrive. Check the transmission fluid level and add fluid as necessary. If the fluid level is low, it's important to also check for any leaks that may be causing the fluid loss.
3. Worn or damaged overdrive band: The overdrive band is responsible for engaging and disengaging overdrive. If the band is worn or damaged, it may not engage properly. A mechanic can inspect the overdrive band and replace it if necessary.
4. Transmission control module (TCM) issues: The TCM controls the shifting and engagement of overdrive. If the TCM is malfunctioning, it may not engage overdrive or cause erratic shifting. A mechanic can test the TCM and replace it if necessary.

It's recommended to have a professional mechanic diagnose and repair the issue, as the transmission is a complex and vital component of the vehicle.

If your 2005 Chevy Uplander LS is not engaging in reverse, it could be due to a variety of reasons. Here are some potential causes and solutions:

1. Low Transmission Fluid: Check your transmission fluid level using the dipstick while the engine is running. If it is low, add the necessary amount of transmission fluid to the appropriate level. A low transmission fluid level could cause problems with the transmission and prevent it from engaging in reverse.
2. Transmission Filter: The transmission filter can become clogged and restrict the flow of fluid to the transmission. If the filter is dirty or clogged, it should be replaced.
3. Faulty Transmission Solenoid: The transmission solenoid is responsible for controlling the flow of fluid in the transmission. If it is faulty or malfunctioning, it could prevent the transmission from engaging in reverse. A diagnostic scan can determine if the solenoid needs to be replaced.
4. Broken Transmission Bands or Clutches: Over time, the bands or clutches in the transmission can wear out or break, causing problems with reverse gear engagement. If this is the case, the transmission may need to be rebuilt or replaced.
5. Torque Converter: The torque converter can also cause problems with reverse engagement. It may need to be replaced or repaired.

It is recommended to have a professional mechanic inspect and diagnose the issue with your 2005 Chevy Uplander LS to determine the root cause of the problem and recommend the appropriate solution.

It's possible that the issue is with the transmission. Here are a few things you can check:

1. Fluid level: Check the transmission fluid level to make sure it's at the correct level. Low fluid can cause the transmission to slip or not engage properly.
2. Fluid condition: Check the condition of the transmission fluid. If the fluid is dark or burnt smelling, it could indicate a problem with the transmission.
3. Transmission control module: The transmission control module (TCM) is responsible for controlling the transmission. If the TCM is malfunctioning, it could cause the transmission to not engage properly.
4. Transmission solenoids: The transmission solenoids are responsible for controlling the flow of fluid through the transmission. If one of the solenoids is faulty, it could cause the transmission to not engage properly.

If you're not comfortable checking these things yourself, it's best to take the vehicle to a qualified mechanic who has experience working on Land Rovers. They will be able to diagnose the issue and recommend the appropriate repairs.

run fault codes and look for TCM module and or wiring insulation deteriation . Additives such as what you have added are not a good idea as they mask real problems and do not do much to help the transmission work better. I would have the system flushed out with an oil change and then have a pressure test done to determine exactly where the problem is . What to describe is a valve body problem from a build up on the parts not allowing smooth operation of the valves.

have transmission fluid and filter changed.most time if transmission not shifting good when cold,transmission filter could be stopped up and fluid thick old nasty burned not circulating good cause some slipping in transmission.

Low transmission fluid is usually the only reason power engages late or slippage occurs. But changing the transmission fluid again would not hurt. The stuff really shouldn't deteriorate like engine oil. Be sure to not run the vehicle many miles until the problem is completely resolved < 100 miles. One easy check would be to make sure the transmission lines are well connected and maintain pressure as well as fluid level. The good thing is that Toyota has a reputation of very good transmissions.

The best case scenario is that your overdrive switch is malfunctioning, and simply needs to be replaced, along with flushing your transmission fluid and replacing the transmission fluid.

The worst case scenario is that you have a band or solenoid in your transmission that is broken and not engaging your overdrive. Your transmission has 3 gears, and when the overdrive is engaged, it simply links 2 or more to the gears together to achieve overdrive. It would seem that something is preventing that from happening when the engine is cold, and simply making the gears spin freely as in neutral.

I would recommend finding a transmission shop to inspect this problem. It may be a simple $100 fix, or could end up costing you a couple thousand for a transmission rebuild. But get the inspection from a transmission professional before performing any repairs. And don't be afraid to get more that one opinion from more than one transmission shop.
Good luck!

If fluid level is good, the hydraulic value of the trans fluid maybe low or worn. If fluid is old or burnt, (never been changed, or high mileage,) sometimes not a good idea to flush. Highly suggest LUCAS (ONLY) Transmission Treatment, carefully read instructions on bottle. Transmission replacement is expensive, following maintance will prove rewarding! If you wait to long to flush trans your worse off!!! Hopefully helpful!!!!

USUALLY YOU SHOULD CHANGE THE TRANY FLUID EVERY 40,000 MILES. MORE OFTEN IF YOU LIVE IN A HOT AREA LIKE PHOENIX ARIZONA. YOU COULD HAVE PROBLEMS IF YOU CHANGE THE FLUID NOW. IT IS KIND OF A GAMBLE. IF YOU HAVEN'T DRIVEN YOUR CAR HARD YOU MORE THAN LIKELY WILL BE FINE. A GOOD INDICATOR OF THE OVERALL CONDITION IS TO CHECK THE FLUID AND DETERMINE HOW BURNED THE FLUID HAS BECOME. GOOD LUCK.

Engine & Transmission Flush

You might have been told, by your dealer or mechanic that your engine oil or transmission fluid are very dirty, & an engine or transmission flush, is recommended. The flush will clean the engine or transmission, & those will last longer. This is only part true a clean engine or transmission will last longer, but I'm not sure that flushing them is the best way to clean them.


What Is An Engine Or Transmission Flush?

Flushing is forcing high pressure of fluid against the normal flow of the fluid. In simple words if the normal flow is left to right, the flush would force the fluid right to left.

This is done by connecting a machine that will force special solvents back through the engine and transmission. The idea is that by forcing cleaning solvents backwards through the system, it will get all the junk and garbage that has formed over time and "flush" it out of the system. In theory this sounds very good, but in practice, it can be dangerous.


The Dangers of Flushing your Engine or Transmission

Flush machines force high pressure cleaning solvents back through the engine and transmission and clean out some of the accumulated junk that has formed, so far all is good. Now the problems start, engines have small passages and galleries through which oil or automatic transmission fluid flow and there are one-way valves that keep the fluids from backtracking for whatever reason.

By using an aggressive cleaning procedure like flushing, large chunks of accumulated sludge are broken off and forced backwards through these galleries and valves and, more often than not, lodge tightly and block them. This cuts off the normal flow of the fluid and causes lack of lubrication in an engine and abnormal or no shifting in a transmission. The results are expensive repairs, or more often, engine or transmission replacement.

That's my knowledge about the subject, hope it was helpful,
Joe.