First a little history. 225k on what is most likely the original trans in my '96 12v. When i bought the truck i knew it had some sort of shudder(seller was honest), but i could not make it happen on the test drive. Turns out only does it when towing, it gives a hard shudder after upshifting, and if i am trying to accelerate at all up a grade, or even sometimes on a flat. Figured it was just bands slipping hard after the upshifts, but it would shake the whole truck.

I adjusted the bands, and that was little help, as a last ditch effort to not be broke, i dropped a quart of lucas in it. after about 250 miles, the slipping stopped, much to my amazement, i've towed to harlan and back, and to uwharrie, with very little slippage. Problem (temporarily) solved, right?

Here it is a month or more later, and i'm experiencing a new problem

Now the trans is not wanting to downshift to first when i am starting from a stop. If i shift it manually it does fine, and it will shift itself a lot of the time when warm. Could this have to do with the lucas being hard on my valve body or something else along those lines??? Basically I am not in a position to spend the money to fix it right at the moment, as I am buying a house and all funds are suspended until that is over.


Any advice on how i might save this thing???? or at least on what would cause it to not downshift properly?

11/19/2008 11:03:25 AM

Sounds like you have some sticking spool valves or solenoids. Lucas is abnormally thick shit, and I do NOT like it. I don't know shit about its thermal stability either.

One thing I would do: get you two pints of SeaFoam TransTune and dump one in and drive for a while (like less than 500 miles). drain your pan, change your filter, and while you're under there, go ahead and check/adjust the bands. Put pan back on and top up with fluid. Might add up to half a pint of TransTune in with the new fluid.

You ARE using Chrysler 7176 (+3/+4) spec fluid, aren't you? You might want to switch to a good synthetic like Amsoil offers...but be sure that it's the proper grade. Absolutely essential that you use a friction-modified fluid. The Lubeguard "short quart" friction modifier plus regular ol' Dexron WILL NOT CUT IT.

11/19/2008 11:22:46 AM

Does Amsoil synthetic cover not cover multiple grades? The BG synthetic is supposed to work in replacement of all major types of transmission fluid.

11/19/2008 11:30:46 AM

Ok, well I will admit i'm running dexron, put it in there about 2k ago when Hurley and I adjusted my bands. I am woefully ignorant of what it actually needs, but i will look into what you suggested. My plan was to get rid of the lucas as well as i could, as i figured it was causing this problem while solving another. I guess i should flush it instead of just changing what is in the pan...

11/19/2008 11:32:40 AM

consider yourself lucky you've got 225k on a 47re!

11/19/2008 1:06:53 PM

Sounds like the person who got 220k out of it and then sold it to him is the lucky one.

11/19/2008 2:52:33 PM

luck, there is no such thing as luck with these trucks. there's never been a transmission that could handle the 6bt5.9


never

11/19/2008 3:52:37 PM

^^ Correct, i bought it with 219k

Also, that owner was not original, but had it for a while, no telling if the trans was replaced before he had it though...

11/19/2008 4:01:34 PM

sounds like the 1-2 shift solenoid to me. somewhat common point of failure on them and other electronic chrysler autos. a bad computer will also present similar symptoms. however, usually in that case it will operate fine when cold, but then start hanging in gears as it warms up (opposite of what you described).

definitely get that dexron out of there asap though! you'll want to flush it or at least drain/refill a couple of times to make sure you get it all out of the torque converter, etc. using dexron instead of atf +3/4 one of the leading causes of premature failure among all the dodge truck transmissions. as i've said on here many time before, mechanically speaking they're excellent units and have an unfounded/undeserved bad reputation due to dumb owners. with proper care, they'll last a long time even under hard use/abuse and never miss a beat. their achilles heel, if you can even call it that, is being neglected. religious maintinance is a must. where other brands of autos might not really be bothered by never changing the fluid, running hot, etc. it's a quick death for dodge truck models. few things to remember:

- follow the recommended fluid/filter intervals to the exact mile. sooner if you drive hard and/or tow.
- check/adjust the bands just as frequently.
- use only a high quality fluid of the correct type.
- add the biggest transmission cooler you can find and fit. two smaller ones will work also. heat is the enemy of any auto, but even more so with dodges.
- get a trans temp guage and DO NOT ever let it run hot. if you absolutely have to for some reason, change the fluid/filter asap.
- turn up the line pressure just a little. this will firm up the shifts, help eliminate a little heat, and help with any excess slipping/shuddering during shifts.

do all of that, and you'll be rewarded with an almost guaranteed long life of service on a new/rebuilt unit. it'll definitely help you get the most out of any used one also, but there's always the chance it's already been pwnt by previous owners.

11/19/2008 5:51:56 PM

^what do you mean as far as adjustments/modifications when you say turn up the line pressure?

11/19/2008 6:54:19 PM

Alright, the flush is a must, i will do that soon.

I run a temp gauge, and have tried pulling the reading from a couple differnt locations, never even thinks about getting hot, even towing in the hills.

I am also interested in how you would bump up the line pressure.........

11/19/2008 9:44:28 PM

fuck all that noise. run 80% lucas, 20% water, with a pinch of sawdust

good to 1200hp

11/19/2008 9:48:08 PM

hey man, i was reading on dtr and the best place supposedly to put your probe is in the hot line to the cooler off of the tranny. i think i got that right. put a t with probe in it, i'll post up the t later when i'm at my computer.

11/19/2008 10:13:50 PM

yeah, that's where you'll get the hottest reading on pretty much anything.

for the line pressure, there is an adjustment screw in the valve body.

11/20/2008 2:06:39 AM

http://www.genosgarage.com/prodinfo.asp?number=VULCAN_VTA

10 dolla make you holla

11/20/2008 11:47:57 AM

i know this sounds idiotic with all the work ive done on the LUNG, but i've yet to locate a non-hard transmission cooler line. right now my trans temp is reading from the existing bung where the trans thermistor once was (it dangleth from a zip tie... no OD for a while when cold ). If and when i find a soft line, that Tee would be the tits.


aside: I've thought about adding a tee at the location of the factory thermistor site, but I'm concerned that stagnated flow from the line into the tee would give an inaccurate reading.

11/20/2008 11:52:25 AM

you could do compression fittings in the hard line also.

11/20/2008 12:06:59 PM

I'm taking it that the temp sensor is a negative temperature coefficient thermistor, threaded body, single wire? or two?

What you should do is fab up a sensor housing, where you neck up to 1" steel tube line with an NPT half coupling penetrating the tubing...and make sure that the sensor protrudes into the flow. Hell, you might even want to do 1.25" or 1". A little temporary velocity loss in the region and a good chance for better conductive heat transfer at the boundary layer.

11/20/2008 2:48:54 PM

^Two wire, got a ~1/2" long nipple that, as designed with it's port in the tubing, protrudes into the flow path.

I like that idea

11/20/2008 3:42:47 PM