Service slants

Motor, Aug 1999 by Juran, Ken

The next problem could be outdated TCM software. But the computer was modified according to the following schedule: As of April 1991, VIN 8A_MA160550 (B3); Sept. 1991, VIN 8C_NA010508 (B4); May 1991, VIN 4A MN081408.

The last condition could be one of carelessness, as the system may not have been returned to its basic setting the last time diagnostics were performed. So make sure to do that when you're done.

As for other causes of the symptoms, Audi suggests checking for any stored DTCs and following through the diagnostic routines for them. But the German carmaker warns not to try to replace the TCM if it's the latest version, because "shift quality will not improve."

Dodge Truck

Clunking noise up front. Some 1995-97 Dodge Ram Vans may develop a clunking noise in the front suspension when the truck is driven over rough roads. Luckily, the cause of the ruckus is just the front shock absorber bushings and/or the upper coil spring isolators. In the former case, order up new bushings and retainers, install them and you're done. In the latter case, take a look at the upper spring seats. If it's clear the isolators have slipped out of position, you're going to have to put in new ones to get rid of the noise.

When doing the isolators, note that the flat or closed end of the coil springs are supposed to be the tops, just in case they were installed upside down to begin vith. In case you don't have a lug nut chart handy, they get 80 to 110 ft-lb on 15-inch wheels. For 16-inch wheels, i-20 threads take 85115 ft-lb and5/8-18 threads take 175-225 ft-lb. Here are the part numbers, should you need them:

Volkswagen

Erratic shifting, no DTCs. All VAV models with the AG4 four-speed automatic transmission up to 1997 are susceptible to developing a condition of no upshifting, unnecessary downshifting or holding gears too long. Unfortunately, there probably will be no DTCs stored in the TCM to help with your diagnosis. So the only avenue toward a fix is to suspect an incorrect oil temperature sensor reading from the "Conductor Strip with integrated Transmission Fluid Temperature Sensor." WV explains how to test this sensor only with a scan tool, so if you don't have European scanner capability, you'll probably have to try a known-good part. For reference, the normal ATF operating temperature of this unit is 230 deg to 248 deg F (110 deg to 120 deg C). At approximately 279 deg F ( 137 deg C), the TCM goes into "hot running program."