277k is plenty of miles. If this is the original tranny, it might be on its way out.
That being said, new fluid is worth a try. You have absolutely nothing to lose here, do you? The myth of new fluid hurting an old transmission is exactly that. A myth. You may not want at power flush and fill, but gently replacing fluid is ALWAYS better than leaving old fluid in the tranny.
Drop the fluid in the pan and replace with the 3-4 quarts it takes to refill. See if that helps.
And test and adjust that TPS!
Simple stuff first before you start shopping for a salvage yard tranny for your XJ!
(Thanks to Joe Peters from NAXJA for this information)
RENIX manual transmission equipped XJs have a three-wire TPS mounted on the throttle body. This manual transmission vehicle TPS provides data input to the ECU. The manual transmission TPS has three wires in the connector. Wire "A" is positive. Wire "D" is ground. Remove the three-wire connector from the TPS. Key ON, measure voltage from "A" positive to "D" ground. Note the voltage reading--this is your REFERENCE voltage. Now, reconnect the three-wire connector to the TPS. Key ON, back-probe the connector at wires "B" and "D". Measure the voltage. This is your OUTPUT voltage. Your OUTPUT voltage needs to be seventeen percent of your REFERENCE voltage. Adjust the TPS until you have achieved this percentage, if you can't achieve the correct output voltage replace the TPS and start over.
RENIX automatic transmission equipped XJs have a TPS with two connectors. There is a three-wire connector, same as the manual transmission vehicles have, and it is tested the same as the manual transmission equipped vehicles--FOR ENGINE MANAGEMENT RELATED ISSUES. However, the automatic TPS also has a four-wire connector. For the automatic transmission equipped vehicles the four-wire connector provides data to the TCU. Disconnect the four-wire connector. Key ON, measure voltage between "A" positive and "D" ground. Note the voltage. This is your REFERENCE voltage. Now, reconnect the four-wire connector to the TPS. Back-probe the connector at wires "B" and "D". Measure the voltage. This is your OUTPUT voltage. Your OUTPUT voltage needs to be eighty-three percent of your REFERENCE voltage. Adjust the TPS until you have achieved this percentage, if you can't replace the TPS and start over.
So, if you have an automatic equipped XJ your TPS has two sides--one side feeds the ECU, and the other side feeds the TCU. If you have TRANSMISSION issues check the four-wire connector side of the TPS. If you have ENGINE issues check the three-wire connector side of the TPS.
For those with a MANUAL TRANSMISSION--the TPS for the manual transmission XJs is stupid expensive. You can substitute the automatic transmission TPS which is reasonably priced.
Without data, all you have is an OPINION!
Past Jeeps: '49 ******, '81 Scrambler, '88 Comanche
Current Jeep: 1999 XJ Sport, bone stock, daily driver.
I work on Jeeps!!
Last edited by tjwalker; 02-07-2011 at 06:32 PM.