Automatic transmission/gearbox does not plug in gear, when setting gear-lever in gear

my xj-s, pre-HE sometimes will not set in gear, when I move the gear shifter from Parking. The car has been used too little and has been standing for the last year.
Sometimes it couples into gear as it should and sometimes nothing happens. Any suggestions on what to look for?

A few thoughts;
Have you checked the trans fluid per the procedure in the manual - with the car running - and confirmed that it is at the proper level?

Is there any difference in behavior when the car is cold vs. warmed up?

Has any work been done that might affect the adjustment of the shifter cable?



Can you confirm that you what type of tranny have ypu got there? I’m not sure about acient XJS henxe asking - should be GM400 I assume.

Definitely your gearbox is fully hydraulic/without solenoids so only issue you may suspect is stuck valve(s) on the tranny’s valve block or corrosion of the baskets that makes it difficult to shift. Nothing major if the car runs fine and it happens only sometimes.

I recommend fluid change - have a look at the process - it’s applicable to every gearbox of that era, here:

Change the oil several times, ride few kms pref. in town locations. Use cheapo fluid (dexron3) then do the last two changes with quality fluid.

Moisture accumulates everywhere when not in use, hence the reason. Old fluid will contribute.

Early pre-HE cars had the Borg-Warner transmission. If the tranny dipstick is on the left side of the engine compartment, you have a Borg-Warner transmission. Borg-Warners use Type F transmission fluid.

If the dipstick is on the right, you have a TH400 GM transmission. They use Dextron 3 fluid.

The changeover from Borg-Warner to the TH400 was sometime in 1979.


Thanks for your answers - They were very helpful and highly appreciated.

For an update:
I wasn’t aware of the fact, that the engine had to run, while checking the oil level, so I thought, that the oil level was ok. In reality it was right below the dip-stick.
After topping up with a litre she was all good again.
I see, that there is a small leakage, under her. which I am going to investigate when spring enters.
Right now I was just having her out for some small rides and shifted some of the fuel lines for the health of her.
I want to give her a larger tjeck up when spring enters.
, I’m planning on selling her to someone who has more time to give her the love she deserves.
She is still in good shape, but is used too little.

again - thanks a lot for your comments.

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