I have an 85xj with the 2.5L I4 and the A904 transmission. I have to hit 40mph before the converter will lock up. I was wondering if there is a way to adjust it down to around 33mph so that it would lock up while driving in town for possibly better mileage?

 

It will buck like a freakin' bronco.

If you drive a lot @ 33 mph, I would expect little if anything in the way of economy.

 

I am usually running between 35 and 40, just can't keep it locked in at that speed.

It seems to pull ok when it is locked. I think the 3:73s help with that, it would still be in the 1800-2000rpm range at those speeds.

 

Does it have a detent cable ?

 

I think so. I messed with the trans on my Eagle but went the other direstion. It locked up too soon so I changed a spring?

Personally, I think locking it sooner is a waste of time. With that carbed XJ, you'd be putting your foot into it harder and the power valve in the carb will open due to low vacuum and any perceived or hoped for fuel economy gain would be worthless.

 

Thanks for the info everyone.

Last Automatic I had was back in 1985, C4 behind a 2.3L in a Mustang. Switched it out for a 4 speed, which I should probably do on this one too. Just not ready to get into that project yet.