What causes shuddering in the transmission

[Steve Roseman]

Throttle valve

I don't know about the 47RE, but on the 47RH the throttle valve affects line pressure. If your throttle valve isn't set right, you could experience low line pressure while cresting a hill as you let up on the throttle thus causing the shudder. As modifications are made, more power is made with less throttle. This ends up causing many problems to a setup that would otherwise be trouble free.

I know the transmission gurus end up adjusting the voltage from the throttle position sensor on modified engines, this might be how they raise line pressures in the 47RE, I don't know.

Since one of you have the RH and the other has the RE, there might be two different solutions.

As for a TC clutch slipping and how much time you have, hard to tell but can't be long. Each time you slip it, you polute the rest of the transmission with clutch material.

I would recommend to anyone to go with an aftermarket converter, you figure out which brand you want cause I won't go there.

 

[Gummel]

Ok I got some answers today I went to Massdiesel’s place today and had him drive it. I was told this I am getting blow by through the seals so the shudder is the torque converter. It will only get worse over time. :{ With the miles that I have 73,000 there is no point in wasting $$$ on that dodge junk. I plan to save my nickels for a complete DTT up grade.

 

[Steve Roseman]

73,000 miles aint nothin'. I have almost twice that many on stock transmission with aftermarket TC

 

[Gummel]

I hear ya but if it is broken what can I do! Believe me the last thing I want to do is spend $3500 on a new transmission:{

 

[Extreme1]

Try the reflash. This is the first I heard of reflashing a '94-'97. 5!



I don't think it is seals but what do I know? When I had my trans replaced with a new one, it still did it.



Right after I bought the truck in '97 with 117k on it I wrote to the TDR (no website) and asked what caused it. I was told "they all do it, push the button".



After adding larger tires (235's) it did it worse so I really don't belive it's the seals.



I'll contact the dealer on Monday. I'd gladly part with $50 to fix it!



Edit: Yes, it will tear up parts! Massive torque switching directions that quick is hard on stuff, especially the T/C clutch at low pressure.

 

[Steve Roseman]

Gummel,

I tried to get back in here last night but I think the server was down:{

If your transmission is shuddering just when the converter is locking up and not all the time when under load, I don't think it's your seals.

I'm not going to try to talk you out of a new transmission. But if you're like me, budget has a lot to do with modifications.

If I were you, I'd either change the fluid out and put synthetic in or add a good friction modifier. This might cure the shudder.

I would really recommend an unlock switch, this way you have control over lockup when under load. TST has a diagram on their site, instead of grounding the wire they show, break the circuit with the switch. http://www.tstproducts.com/tranny_install.html

I will tell you I am no transmission pro, so please take all I say with a grain of salt. I would really like to see some comments from those who are more educated on the subject.



P. S. , I'm not trying to push a product, but mine goes into lockup smooth as silk with Amsoil in the transmission.

 

[Gummel]

Steve, I just changed the fluid 1000 miles ago with the Mopar fluid and filter. Do you think that I can just throw a friction modifier in without draining it? How will this switch help? I am new to this diesel stuff. The shudder only comes when the transmission shifts into OD about 3 or 4 second after it tends to be worse when I am going slower.

Thank you for the advice keep it coming!

Micah

 

[Steve Roseman]

Gummel,

You could probably just add the friction modifier to your current fluid.

The thing about having the switch is, when you are accellerating with or without a load you can keep the converter unlocked. This will add a lot of life to a converter clutch. Another thing, you will know if the shudder is overdrive or the converter locking up. It sounds to me like the converter the way you explain it.

I would also recommend checking the TV cable. Have someone hold the throttle to the floor(with the truck off)and crawl underneath to see if the lever is moved all the way. I can't remember which direction, but if you're under it you'll see. Have them floor it, then see if you can move it any further by hand. If you can move it further by hand, you will need to adjust it. Adjustment is simple and is done up at the linkage at the pump.

 

[Gummel]

The TV cable where exactly is that? I am new sorry for the stupidty. Tomarrow I will add the modifier and hope for the best. I think it is the converter too. I do have a lot of experience with gas but the diesel is new to me.

 

[Extreme1]

No, really!

1) IF IT DOES IT AFTER LOCKUP IT IS A COMMON OCCURANCE!!!



If it does it WHILE the converter is locking up, friction modifier won't fix it.



If it DOESN"T do it when you are accelerating harder, see #1.



If it only does it at a few mph above lockup under constant speed or light acceleration, see #1.



Just trying to save you from trying to fix something that's normal like the T-stat cycling.

 

[Steve Roseman]

Re: No, really!

Originally posted by Extreme1

1) IF IT DOES IT AFTER LOCKUP IT IS A COMMON OCCURANCE!!!



If it does it WHILE the converter is locking up, friction modifier won't fix it.



If it DOESN"T do it when you are accelerating harder, see #1.



If it only does it at a few mph above lockup under constant speed or light acceleration, see #1.



Just trying to save you from trying to fix something that's normal like the T-stat cycling.

I might agree that it's common, and common enough that it might seem normal. But I really don't think this is how it was designed. I am curious which transmission vendor told you this was normal like a thermostat cycling. Not trying to start an argument with you Extreme.

 

[illflem]

Sure it's common but can/should be fixed if you want your TC to last. Use the button or have your lock up mph reflashed. 178k on my stock transmission with only regular maintenance and no lock ups below 50 mph.

 

[Extreme1]

Sorry I blew up Steve!



The great TDR sent a letter back to my inquiry (in '97) stating "normal".



I should be getting to the dealer tomorrow to chat about a reflash, 50 mph would be perfect!

 

[Steve Roseman]

Originally posted by Extreme1

Sorry I blew up Steve!



The great TDR sent a letter back to my inquiry (in '97) stating "normal".



I should be getting to the dealer tomorrow to chat about a reflash, 50 mph would be perfect!

No problem, I didn't take it as a blow up.



Gummel, I was wrong about the TV cable on your truck, you don't have one. On the 47RE like you have, I think the Throttle Position Sensor controls line pressure. I don't know how the voltage is adjusted on it.

I would recommend the unlock switch. I forced my truck into lockup at 43 mph yesterday morning with 8 pounds of boost, no shudder. I don't think the reflash will cure your problem, though it can't hurt to have it done.

 

[Extreme1]

Update! Chatted with the dealer yesterday...

I started out by talking to one of the service writer guys. He spoke to the tech who talked to me directly! (Gotta love that, huh? Then the writer came back on and apologised for having to hand me off to the tech, said he didn't want to loose anything in the translation. ) The dealer is Pommerening in Oshkosh, WI.



Anyway, I made an appointment for next Thursday (3/14) to get a reflash. The tech went on to be sure I understood that he can't go in and adjust the lockup speed. All he can do is look for codes, see what (if any) updates the truck has, and input the latest update. He went on to say that there were several updates to the early Rams due to a lot of shifting complaints.



It will cost me $50 to get done and it will be the second time I've paid someone to work on my truck (first was alignment). I'll report the results next week.



Thanks to MChoquette and Steve Roseman for the reflash info!

 

[lIseminger]

Gummel,How do you turn up the line pressure?

 

[Steve Roseman]

DTT used to have directions on their site but I can't find them. They look like they're remodeling it.

Make sure your TV lever is getting full travel when pushing down on the throttle. This affects line pressure, and should be checked before getting into the valve body.

 

[sam peterson]

might as well add my 2 cents worth---had the shudder when the truck was new just after it shifted into lockup---dealer said it was normal. lockup was at 48 mph. all it did was get worse from that time on. now it shudders on light throttle from 48 to 65. You can't make me believe that at 65 i am lugging the engine. had the re-flash--trans reman with suncoast conv & valve body rework--upgraded driveline--pressures increased--mystery switch. it also does the same thing with OD off in 3rd & lockup---Bill K drove it ---Piers drove it and everybody came away scratching their heads---needless to say that I am still looking for the answer. 75000 miles of grief. ----Sam

 

[Steve Roseman]

Sam, I feel for you. That would be pretty upsetting, especially since it was new.

Did Bill K or Piers have any suggestions when they drove it?

 

[Bigramguy]

I have the shudder as well. I have tried playing with different lockup speeds,but to no avail. I replaced my hanger bearing a while ago (came apart),and the shudder disappeared for a few months and slowly came back over time. Maybe it is a driveline shudder that we are all feeling ? Like the hanger bearing when the rubber gets old ? I know part of it is my slipping TC clutch,which makes it even worse,but just waiting to see if the trans\convertor will make 300000 before the DTT stuff goes in.