Technical Support
Transmission Installation | Torque Converter Installation
Basic Troubleshooting | Stall Test Instructions | Checking Pressures
Fluid Types | Causes of Clutch Pack Burn-Up
AIT'S
INDUSTRIAL TRANSMISSION TECHNICAL SUPPORT PAGES: BASIC TROUBLESHOOTING
One of the most common errors in checking out a transmission problem is ignoring the simple things. The first step is to always check the fluid level. In most lift trucks, this is done while the engine is running. I agree, it is more difficult to do it this way.
If you are having problems upon installation or just after a fluid change, remember to check the fluid level upon initial start up and again after a few minutes. It often takes the system a few minutes to circulate the fluid properly.
The next step is to examine the fluid. Does it smell OK? Or does it seem powerful enough to use as chrome cleaner on the Harley? If the fluid smells like it is burned, or the appearance resembles mud, you know that the unit is going to need an overhaul. Simple: you have to clean out that gunk.
If the oil is seriously burned, the cause of the overheating must be determined. Of course, improper fluid level is the first and most basic reason for this. But it can mean a restriction in the cooling lines, a blocked or restricted cooler or radiator, or a collapsed filter.
The torque converter naturally creates heat because of the way it functions. Excessive heat may be indicative of a converter problem.
Operator abuse is likely to cause excessive operating temperatures. Using the inching pedal as a brake or using too high a gear range will create more heat than the cooling system can overcome. Speaking of the cooling system, remember to check the coolant level and the condition of the thermostat.
A simple problem like a bend or too severe a turn in a cooling line will restrict fluid flow enough to prevent proper cooling. Aeration of fluid will cause overheating. Locate the air leak to cure the problem.
An overheating transmission or torque converter can cause the engine to overheat. The transmission fluid is sent through the cooling lines. Fluid that is very hot will heat the system instead od the system cooling the fluid. When that happens, all the system temperatures increase.
Check tire condition. Badly worn tires can slip on the rims, and give the impression that the transmission is slipping.
Add-on filter can be a problem. Verify that the correct input and output ports have been used. Check the size of the line for possible restriction. Is the lube circuit correct?
Make certain you know whether or not the transmission is sealed from the differential. Sealed units require you to fill the differential with gear lube, as the transmission fluid will not lubricate that portion of the transaxle.
Older transmissions used fill plugs instead of dipsticks. It is more difficult to check fluid level. When in doubt, overfill. Rule of thumb: Over-filling is less dangerous than underfilling in most transmission applications.
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