Overdrive problem?? please help...

[lost86broncoii]

Well i just bought my second bronco ii, 1986 XLT dark blue with silver on the sides, no rust and only 77K original miles

Only one problem with it so far i noticed that when i have it in overdrive(auto trans) it will vibrate when it is about to upshift or at certain speeds like just over 45 and 55. But if i shift it down to drive it won't make the funny vibrations...

i want too swap for a manual any way, but money is a big issue for a few months and i have to make a road trip from Florida to Upstate NY, in a few weeks. I need to know is my trans going to quit on me? Is it something with just the overdrive? Could it be as simple as maybe the drive shaft off balance or tires? i am not a transmission guy so any info you got would really be helpful? should i change the filter and fluid maybe?

 

[reds61on]

My 86 Ranger with the A4LD did that when I first bought it. After searching a lot on the web came across a Corvette sight that indicated OD RPM's being much lower will pick up a miss where drive won't. Result was vibration in OD. I did a tune-up on mine (needed it anyway) and found that plug #2 ws cracked. Once all of the plugs were changed I took her for a spin and no more vibration in OD. Truck ran a lot better as well.

 

[lost86broncoii]

That would be great if its just the plugs, it does need them changed, it needs a whole tune up cause the guy i bought it from hadn't been driving it in a while, i'll change the plugs, cap, rotor, and all that good stuff next weekend and see if that's it. thanks for the info