vibration in drivetrain at low rpm in 4th and 5th gear

chadhargis · **Posted:** Mon Dec 08, 2008 10:39 am

Well, at this point, I'd take a hard shift over the shudder.

Anyone know what the value of the resistor is and have instructions on how to install it?

I'll drag out the soldering iron and give it a shot.

BlackLibertyCRD · **Posted:** Mon Dec 08, 2008 10:48 am

It goes on the transducer plug Strip back wire 1 and 3 and solder the resistor between those two wires.

retmil46 · **Posted:** Mon Dec 08, 2008 11:09 am

I'd be cautious about installing the resistor and raising line pressure, unless you also installed the new style oil pump in the tranny along with the Suncoast.

If memory serves, when we first started installing Suncoasts and Transgo shift kits, there were reports from people with Dodge Ram Hemi trucks using the 545RFE and installing the Transgo and resistor, that if you increased the line pressure too much, it would cause the old style oil pump in the tranny to fail. That may have been in conjunction with using a programmer/chip to raise line pressure even more.

Not saying the resistor by itself would cause any problems, but it'd be worth checking out beforehand.

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

I remember reading something similar on one of the GC or Dodge forums, using the 545RFE transmission. One of the members posted a statement saying that their upgraded power flash, which upgraded the TCM line pressure, had a note saying not to use the Transgo resistor as it would raise tranny pump pressure over 200 psi, which was a bad thing. IIRC, they went to 180 max with their programmer. Could not get Transgo to tell me what they raised it to with the resistor, but if one had a DRBII and a switched resistor, one could measure that easily enough.

I wonder who has just such a setup?

danoid · **Posted:** Mon Dec 08, 2008 1:08 pm

Dawgbyte1975 wrote:

PressureLoc Transmission Kit

A BD PressureLoc increases convertor lock-up clutch applied pressure on 1994 to 2001 Dodge trucks by 30% at light throttle pressure. The kit can easily be installed on the stock transmission and assists in preventing convertor shuddering and transmission slippage.

Torque convertor clutch slippage results in high heat and eventual transmission failure! The higher the HP, the lower the transmission line pressure is, because line pressure is controlled by the position of the throttle pedal. The diesel has so much torque at light throttle pedal movement and thus low apply pressure at the lock-up clutch when the engine is at its peak torque!

You can notice a shuddering torque convertor under throttle at low speeds, and also under heavy throttle with high power engines.

The kit’s function is to increase the transmission line pressure when the lock-up clutch is engaged. The PressureLoc cylinder rotates the transmission's throttle valve shaft to simulate 3/4-throttle travel to increase the line pressure to 90% of what the valve body design can attain at wide open throttle. The resulting pressure must be measured and set when the kits are installed.

The PressureLoc is primarily designed for stock or mildly enhanced engine applications and owners whom have installed an exhaust brake and want some extra protection.

It is not a replacement for a modified valve body!

High horsepower and heavy-loaded applications should also be equipped with the BD Valve Body with larger porting for pressures up to 180 psi.

The PressureLoc increases the clutch applied pressure to 90% of what the valve body is capable of achieving at full throttle when you are only at 1/4 to 3/4 throttle travel. This kit addresses the need for more clutch holding pressure.

This pressure increase remains within the valve body design. The stock valve body has 4.0 G.P.M flow when the torque convertor is locked up with the PresureLoc engaged. Without the pressure lock engaged, this pressure will be 4.0 G.P.M or less, depending on throttle pressure.

I wish they made one of these for the CRD.[/i]

There is no throttle valve on the 545RFE. This kit is for the 46RE / 47RE / 48RE (son of torqueflite 727). That trans had a cable that was connected to the pedal that turned a shaft on the left side of the trans. (2005 & up 48RE used a motor to do this)

The 545RFE uses a bus message to 'know' pedal position. And in any case will boost pump pressure if it detects slip.

fastRob · **Posted:** Mon Dec 08, 2008 3:19 pm

Waiting for the word from the man!

Before you all start soldering pins together ask yourselves, is this the simplest, cheapest thing to do?
These drive shafts have always been suspect in my mind.
I had an old Dodge van that vibrated like this one does.
Balanced the driveshaft and new u-joints, problem solved.

I just hope that is my problem.
Actually I have lots of problems but that is for discussion at the LOstmymind.gov website.

LIBERTYinLIBERTY · **Posted:** Tue Dec 09, 2008 3:34 am

O.K.

I replaced my rear drive shaft u-joints (both of them), I swear that they were the toughest I had ever replaced in 30 years (including farm equipment).
They were rusted worse than a 50 year old vehicle. had to heat them up with a torch while applying 25 tons of pressure on a press.
New ones went in flawlessly.

And OMG! the vibration was gone, the drive is smooooooth!

I would suggest, if you have a vibration, replace them.(cheap repair. under $30 for parts.)

chadhargis · **Posted:** Tue Dec 09, 2008 11:22 am

Humm...you only replaced the rear U-joint? Not the one on the front of the shaft as well?

Or are you saying you replaced both joints on the rear drive shaft?

Now for the fun part, I don't have a press. darn, I knew this wouldn't be as easy as I thought!

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

chadhargis wrote:

Humm...you only replaced the rear U-joint? Not the one on the front of the shaft as well?

Or are you saying you replaced both joints on the rear drive shaft?

Now for the fun part, I don't have a press. darn, I knew this wouldn't be as easy as I thought!

http://www.harborfreight.com/cpi/ctaf/d ... mber=38335

LIBERTYinLIBERTY · **Posted:** Tue Dec 09, 2008 12:16 pm

If you think that Harbor Freight (China made) tool would have done the job, well, let's say it would have been a waste of $32.99 + tax for MY driveshaft :wink:

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

LIBERTYinLIBERTY wrote:

If you think that Harbor Freight (China made) tool would have done the job, well, let's say it would have been a waste of $32.99 + tax. :wink:

You're too late. It already did the job. And it is cheap chinese junk, but it did the job even on a rusty spare driveshaft. Depends on how motivated you are.

I love a sample of one representing all that is to come.

PS - I might add I almost always buy Miller or OTC good quality tools. This time, I needed to get it done, Napa didn't have it to sell, the Zone didn't have it to rent, the local chinese outlet aka Harbor Tools had it. If it had broken after one use it would have met the goal of getting the job done. Surprisingly, it looks a lot like my Miller ball joint press for the Libby. Just didnt have the ujoint adapter or the time to wait for it. There was a highly motivational, high priority job waiting in line - my wife made sure I didn't spend too much time on this one. :-)

LIBERTYinLIBERTY · **Posted:** Tue Dec 09, 2008 12:34 pm

I am glad it worked for you.

Ah yes, the dreaded wife's priority list (i.e.-take out the trash)that supersedes any of our GREATER GOOD FOR MANKIND jobs, we (at least us married guys)all have these.

I have access to a machine shop with several presses (thank goodness)in my case.

BlackLibertyCRD · **Posted:** Tue Dec 09, 2008 12:36 pm

I used lots of Harbor Freight tools and not have any problem with them. There is an outlet a few miles from me so I have a few things from there.

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

LIBERTYinLIBERTY wrote:

I am glad it worked for you.

Ah yes, the dreaded wife's priority list (i.e.-take out the trash)that supersedes any of our GREATER GOOD FOR MANKIND jobs, we (at least us married guys)all have these.

I have access to a machine shop with several presses (thank goodness)in my case.

You are very fortunate. I used to live in another state many years ago where lots of small machine shops were available for small jobs. Even when I was a teenager, the local parts house had a machine shop that could bore out a block, grind valves, or grind crankshafts with good results. I tried locating one recently and found that most of those have long been out of business. Same problem exists for the US military, when they attempted to reset a large number of armored vehicles several years ago, due to accelerated wear on vehicles. Problem was, the big 3 had outsourced so much work to China that thousands of trained machinists and the businesses that employed them were no longer around in the rustbelt area. This transistion occured relatively quickly, from the 90's into 2003. Now they set up a tent city in Texas where contractors work away at them as best they can. But this is getting far off topic.

chadhargis · **Posted:** Tue Dec 09, 2008 1:01 pm

I have a Harbor Freight here in Nashville, two of them actually.

Wonder if they have the tool in stock? Wonder if the local Napa has the U-Joint?

I might have a weekend project to do.

Of course, I could just drop the drive shaft out, put the Jeep in FT4WD and go for a drive in my then front wheel drive Jeep. If it's truly a problem with the rear U-Joints, then I won't get the shudder if they aren't there.

Is my logic flawed? Is there any reason I shouldn't try that?

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

chadhargis wrote:

I have a Harbor Freight here in Nashville, two of them actually.

Wonder if they have the tool in stock? Wonder if the local Napa has the U-Joint?

I might have a weekend project to do.

Of course, I could just drop the drive shaft out, put the Jeep in FT4WD and go for a drive in my then front wheel drive Jeep. If it's truly a problem with the rear U-Joints, then I won't get the shudder if they aren't there.

Is my logic flawed? Is there any reason I shouldn't try that?

AutoZone may have it to rent for a refundable deposit. Nothing wrong with the test logic, just take it easy on that front driveshaft. It wasn't really sized to handle the entire vehicle by itself.

chadhargis · **Posted:** Tue Dec 09, 2008 1:07 pm

As long as the front shaft will take me gently up to 50mph, and then to 62mph.....that will prove whether or not the shudder is from the U-Joint or not.

LIBERTYinLIBERTY · **Posted:** Tue Dec 09, 2008 1:09 pm

The youth of this country since the mid 80's thinks that working with your hands means you can run a playstation controller. They do not get trained at an early age how to maintain mechanical equipment. (just and old farm boy showing my age, sorry). a lot of the machine shops are gone because the owners have retired and no younger ones are going into the business.

mackruss · **Posted:** Tue Dec 09, 2008 1:11 pm

chadhargis wrote:

As long as the front shaft will take me gently up to 50mph, and then to 62mph.....that will prove whether or not the shudder is from the U-Joint or not.

No you'll get the 55mph shudder cause you dont have a fuel pump :lol:

chadhargis · **Posted:** Tue Dec 09, 2008 1:23 pm

Well...I'd like a fuel pump.

It's on the list of crap to do, along with the Racor.

I plan on keeping this vehicle until it falls apart (which with the shudder won't be long).

I really wish someone who is a crack wrench on these things would organize a "tech day" where we could all converge and do mods to our vehicles as a collective group. One person assisting with SEGR. One assisting with U-Joint replacement. One assisting with lift pump installs. One assisting with fuel head replacements.

Can you imagine how much fun that would be, and how much we'd all get done as a group?

vibration in drivetrain at low rpm in 4th and 5th gear

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