We've been using our '95 X300 4.0 as a daily driver for several years with reasonable reliability. The transmission went into limp mode last week & I'm seeking possible solutions without having to replace the trans. Any advice is appreciated.

Symptoms: Trans warning light comes on only after having been in reverse, however, in drive it seems to be second, and can be manually shifted into third. Does not shift automatically. Won't go into reverse until after it's been in drive.

Thanx,
Ray

 

Hi Ray,

I assume from your description that the Limp Home Mode (LHM) recurs even after restarting the car?

With the ZF 4HP24 transmission in your car, the odds are good that your problem is electrical or electronic rather than mechanical, but the first thing to do is to confirm that the transmission fluid is clean and bright red and comes to the COLD line on the diptstick. LHM is triggered if the system detects slippage in any gear due to low fluid. It's better to measure the fluid level when hot, but given the LHM it would probably be best not to drive the car until you've identified the cause.

Low battery voltage can cause strange hard-to-diagnose gremlins, and low voltage to the TCM will trigger LHM and a Diagnostic Trouble Code (DTC). Have you had any signs that the battery is not 100% healthy?

The next step would be to have the car scanned for any stored DTCs, since LHM is typically accompanied by a code that indicates the cause. I am attaching DTC Summaries manuals for the transmission and engine so you can look up the definitions of any stored codes, as well as the Dealer Service Training Manual which explains the operation of the transmission and control systems. If you don't have an OBDII scanner, most auto parts stores will scan the codes for free.

If you decide to drive the car to a store, check the transmission fluid level while it's hot. Park on a level surface, and with the engine running, move the gear selector level through all the gears, pausing a few seconds in each gear. Put the lever back in Park and check the fluid level. It should be exactly at the HOT mark. Overfull can cause issues just as underfull can.

If you'll report any fault codes here, we'll try to help (please tell us all codes, not just ones that are transmission related).

Cheers,

Don

 

Thanx, Don. I've confirmed battery is good. Haven't read the codes yet. Fluid was low, and brought up to full & rechecked. It'll be tomorrow before I can check any further.

Again, my thanks!
Ray