This is my first time here so here it goes. I bought my 88 bronco 2 weeks ago. The problems I am having are the transmision shifts real hard in a out of overdrive at 40 to 45 mph when you let off the gas petal, the idle on the truck goes up and down and it sometime dies after starting, but once it warmed up it is fine, I have slack in the steering, but understand that it is in the gear box. The last problem is when under exceleration I can here the rocker arm tapping.

any help on this would be great

thanks


1988
E. B. Bronco
302
AOD

 

Could be several things. Sounds like possibly dirty throttle or vacuum leak(s) for the dying and rough idle. I don't recall if the AOD is still vacuum regulated but if it is (someone out here knows for sure), vacuum leaks can cause the hard shifting as well. Otherwise, fluid and filter change on the tranny couldn't hurt.

Based on the symptoms you have described, it sounds like a few thorough routine maintainance projects would be the place to start.

Tune up including fuel filter and some good throttle body cleaning, oil & filter change, tranny fluid and filter change.

As to the steering concerns, there are a multitude of bushings and brackets that can get worn on TTB trucks. The thing to do is raise the front of the truck, have someone turn the wheels for you while you look at the components in question. In addition to ball joints and tie rod ends, the TTB has axle pivot bolts and raduis arm bushings that, if they are worn, will dramatically affect steering.

 

thank for your reply do you know how i could find a vac. leak in the trans. also do you know of a adjustment on the throtle cable to the trans. as far as the idle first time in the morning it fine after I come home from work and get back out is when it wants to act up and dies after about 2 tries it is fine. maybe a sensor? I forgot to ask about one thing the ABS and brake light come on now , but do not alway stay on.

I plan to take it to a trans shop for the fluid change and hope they can find the other problem to. I also went and bought plugs, cap, rotor, air filter, gas filter, I had the oil changed already in it

I plan to change this all tommorow. will let you know if this fixes all the other problems

THANKS

 

First, the problem sounds like something thermal related. If the problem subsides after the engine warms up, you may be chasing a thermally related problem.

If the tranny is vac. regulated, there will be ONE vacuum line running down to a point on the tranny usually via a metal tube. It provides the regulator with the necessary vacuum to shift properly. Replacing the regulator is the only "fix". Vacuum does not provide any further assistance to such automatic transmissions.

There is a procedure for adjusting the shift cable but I don't know it. Someone here does or a good service manual will have the info..

EFI trucks are notorious for having the IAC get filthy and cause idle problems and eventually starting problems. Its a solenoid and valve located on the driver's side of the throttle body in 302 and 351 equipped trucks. The solenoid fails ocassionally too. Doubtfull that this is the source of your shift problems but could be the problem with it dying on the first few tries. When I replaced the IAC on my '92 the shift points improved though.

ABS light will come on for various reasons. Many people here have discovered that the sensor in the top of the rear axle housing is to blame and merely requires a good cleaning. There is one bolt holding it in place. Remove it and wipe the sensor clean. No need to even disconnect it from the wiring harness. Put it back in place and see if the problem continues. On the outside chance that it does, someone here can tell you how to get the info from the ABS computer to troubleshoot this problem.

Something to keep in mind when doing any service to the truck that deals with sensors, or engine/transmission controls that are electronic, disconnecting the battery for five minutes will clear the stored memory in the computer thereby erasing the "faults" that may be otherwise "remembered" by the onboard computer.

 

Here is my unintelligent thought on the ABS/Brake light...have you checked the brake fluid level? I know I had a similiar light on and off and thought to myself, CRAP, but it turned out to be the fluid level and parking on an incline...My 2 cents