It’s not what you think. When your customer complains that their vehicle’s engine surges, your first thought is to look for an engine performance related cause. But this is not always the case. This was the predicament one SureTrack community member faced when his customer came in with their 1997 Chevrolet Pickup K3500 6.5L Diesel, complaining the engine was surging.
Diagnosis
The technician first started by confirming the customer’s complaint and finding that the engine was indeed surging. He continued to inspect further and had found the automatic transmission did slip intermittently, which gave the sensation of the engine surging. With this in mind, he decided to perform a visual inspection of the automatic transmission fluid, which he found was at the proper level.
With the fluid not being the issue, he continued the search by connecting an oil pressure gauge to the line pressure test port. Using the scan tool to command the automatic transmission pressure control solenoid to increase the line pressure, the tech found the actual line pressure reading on the oil pressure gauge did not match the commanded pressure intermittently. He removed the transmission pan to perform a visual inspection and found that there was actually no excessive metal and clutch material in the pan. Finally, he connected an automatic transmission fluid cooler flow tester to the automatic transmission fluid cooler and found the fluid flow was below specification, indicating it was restricted.
Fix
The restriction was a sure sign to the technician to flush the automatic transmission fluid cooler. After a test drive, the Chevy Pickup was operating to perfection, and another customer is leaving happy!
Real Fixes from Mitchell 1’s SureTrack® expert information resource are documented issues from actual shop repair orders and community discussions. Read the Real Fix in the Mitchell 1 ShopConnection Blog.
