Engine/Transmission (1994 - 1998) Bombed with Diesel Dynamic stage2, now it shudders!

[DieselpowerDude]

Well, last year in June I installed the DD2 kit plus the transmission components (see my signature) all at the same time (mistake?). The truck has lots of power, runs great, but:
At about upper 40s miles per hour, when the converter looks up the overdrive gear, the rpm drops to the lower 1000s. If I now apply some go pedal, even the very lightest amount of it, the truck horribly shudders. I add little more then the slightest amount of go pedal and it smokes very bad. It feels like I am lugging the engine because it locks up at too low an rpm. My solution is to unlock the converter either by turning of overdrive, tip the brake or sometimes taking the foot of is enough.
It does this in all gears above 28 mph when it looks up with rpm very low and me not giving it a lot of go pedal, like being in busy traffic going slow, meaning I can't accelerate away quickly. If I accelerate quickly through the shifts then this is not a problem.
Everything is installed by the book. Transmission adjustment and pressures has been checked by the expert several times.
I have disabled the torqlock and exhaust brake to no avail. Its not because I have the converter "forcibly" locked.
Diesel dynamics thinks that the injection pump might not be tuned correctly by factory or is bad. Other place thought that the plate is not adjusted correctly. Well I got very differing opinions from different places. Even though to me it feels like it simply locks up toooo eaarly everybody else things it is an engine fuel problem.

Otherwise truck has shiittloADS of power!
Also it was running fine before.
Truck has 120000 miles, my own warranty, #ad
or #ad
?

Before a get that big trailer I like to get it fixed, help!

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95 2500 RC,SLT, loaded, Air lift, no EGR, 285s on cool alu rims. DD stage 2, BD Valve body,TC and Autoloc,
BD brake. Transtemp,EGT and Boost on A-pillar.
Cumming soon: Cat delete pipe is sitting in garage awaiting installation (whats the delay?)
I tow a car trailer, 11 foot cabover camper, planning for a 29foot fifth wheel, any suggestions?



[This message has been edited by DieselpowerDude (edited 02-08-2001). ]

 

[Piers]

What are your WOT upshift points? What is your TPS set for? The higher the voltage setting the later the tcc engages. I don't care whos trans package you have installed, with the lock up clutch engaging at 1000 rpm you're going to kill the clutch lining soon. Adjust your TPS to 1. 2-1. 4 volts at idle position, that will help delay lock up.

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Piers, BD engine R&D

 

[Joseph Donnelly]

Also check transmission line pressure. It's most likely too low to hold the lockup clutch tight. Then you have more torque with the DD injectors which tends to slip the lockup clutch even worse. The engine vibration will be very hard on the transmission in general, too.

 

[DieselpowerDude]

It locks up at about 1200 rpm. Where should it lock up?
Up shift points I have to check that out again but when we did it it was... correct.

TPS: I tested it and it was much higher then 1. 4 volts. It was closer to 5 volts. Is this different in 95 vs later trucks? I then proceeded to buy a new TPS (they charge to much!) and it was the *same* voltage reading, which I then adjusted to the lowest reading. No change in problem.
Transmission line pressure was checked and considered fine (I dont know values anymore).
Also with the BD Valvebody I thought this was less of a problem. Torq converter is BDs "medium Stall" unit which they say is the right one for my application (trailers) and power.

The reason I havent converted BACK yet (big bummer, i would say) that I am hoping to make it to Vegas to Diesel Dynamics in summer. But I do find it hard to believe that it might be Injection pump.


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95 2500 RC,SLT, loaded, Air lift, no EGR, 285s on cool alu rims. DD stage 2, BD Valve body,TC and Autoloc,
BD brake. Transtemp,EGT and Boost on A-pillar.
Cumming soon: Cat delete pipe is sitting in garage awaiting installation (whats the delay?)
I tow a car trailer, 11 foot cabover camper, planning for a 29foot fifth wheel, any suggestions?

[This message has been edited by DieselpowerDude (edited 02-08-2001). ]

 

[John_P]

DieselpowerDude:

I had a similar problem like yours
after I had "major" pump mods and
the installation of the 370 injectors.

My truck would "shudder" as you describe
after lockup at about 55 M. P. H. I had
a "BD Pressure Loc" installed and that
completely took away all the "shudder. "
Apparently my line pressures were too
low to handle the increased H. P. /Torque.
The transmission seems to shift and
function much better since the install-
ation of the Pressure Loc.

Hope this helps you!

---------------
John_P

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Red '96 4x4 2500 Auto 3. 54, TST #5, Major Pump Mods(By "Scheid Diesel") 370 Diamond B Injectors, Gov. Spring kit, AFC Spring kit, Banks Exhaust, Prime Loc, Cummins Chrome Kit,Psychotty Air Filter, Pro-Torque Converter, BD Valve Body, BD Pressure Loc, Isspro Gauges, Sendel 16" Alum Wheels w/ 33" BFGs

 

[DieselpowerDude]

Yes, the pressure loc. BD, yes BD told me I didn't need it. But John you are the second one to mention that. It seems that it is worth the try.

Thanks, John

I let you all know if it worked.

Dieselpowerdude

 

[sam peterson]

I also have a shudder problem at lockup 48 mph untill 65 mph on light throttle. i have a mystery switch installed to confirm lockup. Can the trans still cause the shudder with the switch confirming lockup. How can a torc loc help in this situation?
My trans has been upgraded with a suncoast conv & transgo kit already. sam

 

[DieselpowerDude]

The BD Autoloc switch that I have is essentially a fancy mystery switch so I can "confirm" lockup also. All it does is lock up the TC at my command. The pressure loc will put more pressure into the TC a low throttle when pressure are normally very, and in my case high power at very low throttle, *too* low.

I am learning fast. I hope this fixes it.

 

[Piers]

There are 3 wires going to the TPS. it's the middle one you have to check for voltage. One of the others is ground the other one is the 5 volt reference. spec is 1 volt + or - . 2volts with throttle at idle position key on engine not running. Plus is better 1. 2-1. 4 is best for a bombed engine. check out yor WOT shift points, should be 2400-2500 rpm. there was a TSB bulliten out for the 94 trucks, they had to reprogram the computer so lock up would occur at a later mph in overdrive, might apply to your 95 truck. I'll post the TSB # tomorrow.

------------------
Piers, BD engine R&D

 

[DieselpowerDude]

Piers, what do *you* think about the BD pressure loc solution?
I'll check the TPS again tomorrow.

 

[azgearpro]

I had that problem, until I added DTT full transmission mods. The truck runs 100 times better now Special thanks to Bill Kondally for the A-1 quality Torque convertor,valve body and super customer service. I also have to say thanks to fred@canyonstatecomponents.com for the install, and Piers for the advice.

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96,2WD 3/4t ext. cab-DC,just added DTT torque convertor with valve body,tst #4,full pillar guages,5th wheel setup
wanting to add 2-3 lift, and rig style volosity stacks. Dynoed Horse power?

 

[MMcCallie]

The problem you're describing sure sounds like a torque converter on its way out. I've been there a couple times. You'll find out for sure eventually, when its too late. I recommend transmission upgrades, then see how it is.

 

[JoshPeters]

The problem you're describing sure sounds like a torque converter on its way out. I've been there a couple times. You'll find out for sure eventually, when its too late. I recommend transmission upgrades, then see how it is.

I'm sure this issues has been either solved, or fully failed by now... .



The beginning post date is in 01.



JP

 

[Extreme1]

And the fixes are known: TSB for the early shift and 181 or 191 delivery valves for the shudder.