Questions and Answers

A Shiftless Jeep Wagoneer Q. I have a 1988 Jeep Wagoneer, 4 liter with a 4 speed automatic transmission. I have had it about a year with no previous problems. I went to drive it the other day and it would not shift until the rpms were around 5,000. I have since changed the transmission but am still having the same problem.

A. First thing to do is a Manual Shifting Test. This test determines if a problem is related to a mechanical or electrical component. Stop the engine and disconnect the TCU or the TCU fuse. Road test the vehicle. Shift the transmission manually into each gear range. The transmission should operate as follows:

• Lock in Park
• Back up in Reverse
• Not move in Neutral
• Provide first gear only with shift lever in 1-2 position
• Operate in third gear only with shift lever in 3 position
• Operate in overdrive fourth gear only with shift lever in D position

If the transmission operates as described, the transmission itself is fine and the problem is electrical in nature. However, if the forward gear ranges were difficult to distinguish, all feel the same, or the vehicle would not back up, then it is an internal transmission problem.

CAUTION: Do not overspeed the engine during the next test step. Ease off the throttle and allow the vehicle to slow before downshifting.

Continue the road test. Manually downshift the transmission from D to 3, and from 3 to the 1-2 position. Then manually upshift the transmission through the forward ranges again.

If transmission operation is okay, perform the stall, time lag and pressure tests. If a transmission shifting problem is encountered, again, it is an internal transmission problem.

The stall, time lag and pressure tests need to be done by a Chrysler Dealer or Transmission Shop. I assume you have checked the Transmission Control Unit (TCU) for any stored codes.

This can also be caused by an incorrect gearshift control linkage adjustment or incorrect throttle linkage adjustment.