I have a 67 dart w/ a slant six and a 904 tranny. I've got a stock motor with a 2bbl conversion and a 71 carter bbd. I've noticed this problem getting worse and worse. If I rev the engine (floor it) from idle, in park or neutral, the engine does fine. No stumble or hesitation. If I do this while the car is in any gear, the car hesitates and sometimes dies. This used to happen only when I floored it (while in gear). Now it does it at 3/4 throttle and it is getting worse. Even when the engine is warm, it will hesitate and come close to dying. I really need to figure out this problem as this car is my daily driver. Does anyone know of a Tranny shop that will work on older cars? I live in the Indianapolis area.
I could use any info at this point!!
Thanks

Are you sure it's the tranny? If your engine is stumbling when you floor it, that sounds like an engine related problem not a tranny problem. It sounds to me like it might be time to rebuild your carb.

Brian

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Flyin' Brian

74 Duster, 225, rear-mounted blow through turbo at 12psi boost, street/strip car
"Sixy Beast"

I reread your post and I take back what I said about rebuilding your carb. I would look at adjusting your idle speed and your idle mixture. When your tranny is in gear, it puts a load on the engine which will drop the idle rpms slightly. When its in park or neutral, the engine is not loaded.

Brian

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Flyin' Brian

74 Duster, 225, rear-mounted blow through turbo at 12psi boost, street/strip car
"Sixy Beast"

The carb is "brand new" from autozone. I've got the idle up to about 850-900 rpm in park. I think it's the tranny because I've checked the fluid, and it looks more like regular motor oil. It's not red and it has the same texture. And since the problem seems to be getting worse, thats the only thing I could come up with.

Yikes I would definitely flush and fill your tranmission fluid. I haven't heard of bad tranny fluid causing the symptoms you describe. I am still leaning towards it not being a tranny problem. But I admittedly do not have a ton of mechanical experience either. I would also check for any possible vacumn leaks on your carb/intake. Hopefully some other guys on here can help you out more than I can.

Brian

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Flyin' Brian

74 Duster, 225, rear-mounted blow through turbo at 12psi boost, street/strip car
"Sixy Beast"

Do you have an electronic ignition? If you have one is everything in good shape on it? I.E., is the ignition newish the wires good and the connectors not rusty. That would help a bit, not fix the hesitation, but might be part of the problem. I guess I can only give you the basic advice of replace your spark plugs if you haven't, check your distributor and see the condition of it's contacts, and check your coil wires themselves. I talk about the ignition system so much because I've got hesitation on my 73 Dart and I've found that playing around with that system has yielded the best results while being the simplest to do. Can't say I've ever had hesitation as bad as yours except in the coldest of conditions but maybe the advice would help. Good luck!

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My car may be slow to sixty, but at least it's been reliably slow to sixty for more than thirty years.

Your trans sound like trouble, but not the problem here. If it was toasted, the engine would rev up, not stumble, as it slipped. I would go over the intake looking for vacuum leaks first, then probably go into the carb next.

The ignition is not electric. The distributor is also brand new and so is the rest of the ignition. What is the best way to check for vacume leaks?

I just read in Mopar Muscle (May 2004) that a guy in the tech section pg 112 "Hesitant Hauler" seems to have the same problem I have. They say it could be the torque converter stall speed. Does anyone know the stock converter's stall speed? Could these two problems be related?
Thanks!

A high stall convertor "feels" like the trans is slipping because the engine revs higher before the convertor "grabs". Stall speed is built into the convertor and doesn't change with wear. Since you have a bad stumble, not a "revs up before moving" problem, I think your problem is engine related. Some folks use a shot of carb cleaner at any suspect gaskets/joints to see if the idle RPM changes. This may work OK for a V engine, but on a slant, the exhaust manifold is right there and there is a fire risk, so I wouldn't recommend it. Instead, mix up some soapy water and slather it on the gaskets (intake to head, carb base) while listening for a change in idle speed. When the engine fluctuates, you'll see the bubbles getting sucked in by the vacuum. And you get a clean engine to boot! A bad pcv valve or brake booster can also cause major vacuum leaks.

WHEN WAS THE LAST TIME YOU ADJUSTED THE VALVES??,
MY LITTLE 170 DID THE SAME THING, KEPT LOSING POWER, I FINALLY ADJUSTED THE VALVES & IT NOW RUNS GREAT(SMOOTH IDLE)& DECENT PERFORMANCE. ALSO YOU SHOULD CONVERT TO A POINT -LESS TYPE IGNITION, PETRONIX $60/ MA MOPAR?? ETC... GOOD LUCK, ONCE YOUR VALVES ARE A DONE THEN RE-CHECK YOUR TIMING & POINT DWELL, THEN ADJUST YOUR CARB. GOOD LUCK!!!!

It is possible for the problem to be in the converter(it is quite rare with a stocker) as the sprag can go away in the converter,This will give the condition you are talking about! As soon as you put a load on the converter it will"lock up" and almost kill the motor!!! This problem will let the motor idle perfect in gear and as soon as ya touch the gas,it will almost die. I have not had this happen with a stocker,but i have had this 2 times in the last 30 years in my drag car, Good luck..........Bill

I'm shooting for choke problems...my 2 barrel volare did the same thing.Idisconnected auto choke and hooked up a manual choke.bingo no hesitation..It seems to me that most of these old mopars are VERY choke sensitive...