Bucking At Low Mph

[topdri]

I have a 1990 Bronco with a 302 and AOD trans. Recently, it started to buck once it shifts to 3rd gear, which happens to be at a very low MPH (between 25 and 30). Could it be that it is shifting too early? It does not do it all of the time ... it seems to happen more once the engine/tranny warms up. The RPMS are not affected, which leans towards the drive train, possibly. Has anyone else encountered such issues? There are no strange noises or such ... it bucks until the MPH gets up near 35 or 40 MPH then all is fine. Is there a way to change the shifting patterns on this Bronco? I am a new owner - since August and have had many issues with this truck. Me give up? No way! Any help is greatly appreciated...

 

[Shadow_D]

Welcome to the Bronco Zone

First thing I would do is change the tranny filter and fluid.
Look at the fluid for metal shavings, if you find any then it is time for an overhaul.
My guess is once you change the fluid and filter it should clear it up for the most part.
Good luck

 

[topdri]

I changed the fluid and filter right after I bought it in August. I will check the fluid level. It does not appear to be leaking, so I don't think that is it. Thanks though! It always happens when it shifts into 3rd gear and not all of the time. Again, I think it has to do with shifting too soon. The RPM at 30/35 is like 1000. Seems kinda low to me. Next ...

 

[4xfan78]

You can buy an aftermarket valve body for that tranny out of summit or jegs. Pretty easy to install, if you think its the problem. One more reason 4spd's are better. )

 

[Broncoholics]

This sounds like low fluid level. Mose times you have to check the tranny fluid level the next day after replacement. Reason why is you add the fluid down the dipstick tube and get false readings. Its happened to me a few times and found it was a full quart down... :-&

 

[topdri]

I will check the fluid level tonight and I will look into a valve body as well. I am fighting a radiator leak right now. This truck has been a nightmare, but I am not giving up (not yet). Yes, I know a manual would be better but this truck is more for trips than anything else. I have a 5.0 '89 Stang 5 speed that puts out around 475 HP. That is my toy ...

Thanks for your suggestions ... I will report back my findings. Bronco Zone Rocks!

 

[topdri]

The fluid level is fine in the truck.

I spoke to my mechanic today and he said that there are adjustments that can be made under the hood (on top of the engine) - some kind of sliding mechanism that controls when the truck shifts. The fact remains that it shifts into 2nd and 3rd way to fast without stomping on the gas. Going into 3rd before 30 MPH is rediculous.

If anyone has more ideas --- I am all eyes.

Thanks,
Todd