Hey guys it's been a while, dealing with a house robery but thats another story.

I have this horrible stuttering at about 65-70 going up hill in overdrive. Thought it was the engine so changed plugs wires and cap set timing to no availl. When this stuttering is occuring and I shift to 3rd it still does it but faster with the rpms. It doesn't go away until i get to level ground. The engine does not stutter in any other gear at any load rangejust starts in od an continues until level ground. Could it be the tranny or the engine and or what could be causing it?

 

Sounds like possibly a loss of tranny fluid pressure though I'm not sure just why. Of course, could be a torque converter on its way out too. Lack of good pressure and/or torque converter not holding could cause these symptoms I would think. If you put the tranny into a non-moving gear does the stutter cease? Yes I realize that takes the load off the engine but if the engine is running smoothly, the next thing in line is the tranny and being limited to a certain gear under probably the hardest conditions it sees would lead me to lean towards a tranny related problem rather than engine. Do your RPM's jump around when this happens? Just trying to get a clear idea of what you are experiencing.

 

Yes the stutter ceases in a non moving gear.
No the RPM's do not jump but the do fall with the slowdown in speed.

 

Sounds like u might be starving for fuel, try, on level ground, flooring it from a stop sign, or light, till u hit 65 or so. see if it studders at all through this.

 

That sounds even more like a tranny dilema over an engine problem. The engine gets well above the RPM range that its at while climbing in OD when its moving through the other forward gears. If it were engine related I would think you would get the same kind of thing in the other gears under the same conditions. i.e. it starts to stutter at 2000 RPM in OD so if the problem were engine related it would be more likely an engine problem if it did this every time the engine hit 2000 RPM no matter which gear the tranny is in. Since this is NOT the case, I would lean much more towards a tranny problem.

"No the RPM's do not jump but the do fall with the slowdown in speed".

And that makes sense. They should do that. You might check transmission fluid, filter and....AOD, I think its still vacuum regulated. DOH! Something just dawned on me. Check the regulator and its vaccuum connections. The regulator requires a certain amount of vaccuum to maintain shift functions. If for some reason you are getting weak vaccum supplied to it, it will not function properly. Under load, like uphill in OD, your manifold pressure drops anyway effectively reducing the overall amount of vaccuum available to run vaccuum operated accessories. So combined with a poor vaccum connection or bad regulator this may be the result. I may be grabbing at straws here but, its my best guess based on the info.

 

wello, I was thinking about that too, but if the tranny was slipping, I think it would show a little in the RPM gauge. Just a little 100 or change. But then again, I'm sure that the stock unit probaly wouldn't pick it up either, so...

 

atleast they didnt take the bronco

 

U lost me?

 

I had a 73 hiboy with a 390 that did what you are discribing. and a week later lost the upper timing gear. How many miles are on your motor. might be due for a change. because the gear was worn it would surge while driving. not a lot but enough to notice something was going on. I thought it was a fuel problem at first .

good luck

 

motor only has 73000 and the tranny was rebuilt last spring but I will check all of your sugestions thanks

 

fuel filter might also be clogged, i would replace it as well.

 

[QUOTE]Originally posted by buckeyebronco
[B]Hey guys it's been a while, dealing with a house robery but thats another story.

 

[QUOTE]Originally posted by Trucky18
[B]Oh, ok, I understand now, I was lost when i read your last post, wasn't sure who u were talking to-lol

 

Check the fuel pressure during the stuttering. The Craftsman gauge is long enough to run out the back of the hood and stick in the windshield wiper so you can watch it while you drive.

 

hey buckeyebronco,

I know it was a long time ago, but what fixed this problem...kinda sounds similar to mine. Thanks.
GMAN