j-fox

When was the last time the fluid was changed?

gmctd

A TC does not multiply torque at hiway speed and rpm - only at low input shaft rpm when the engine-coupled drive impeller is rotating much faster than the driven turbine on the input shaft and the stator is locked - as turbine rpm increases and stator begins rotating, TC becomes a hydraulic coupling - TC should be well past stall rpm at hiway speeds, aftermarket TC's are 'tighter' than oem, have very low stall rpm - torque multiplication is zero, torque loss due to hydraulic coupling slippage can be high, generating heat due to unequal rpm of drive and driven member - TCC lockup increases efficiency to near 100% - increased TCC lockup is part of the enhancement built-in by the a\m trans shops - be thankful.....be very thankful....................

A modification to the valve-body is required to prevent that shudder, iirc

Wikipedia is not the end-all, be-all source for comprehensive knowledge in any field - wanna know about TC's and TCC's, go to an automotive site, incl some of the aftermarket transmission vendors

cLAYH

Last May when the new TC and VB went in...

rammike

I do, my lock-up acts up occasionally so I do use a manual lock-up switch when that happens, towing approx. 10,000lbs. I like it locked ASAP, that's the only way to get it up to cruising speed reasonably fast.

cLAYH

The TC and VB were bought from DTT at the same time so I hope the VB was modded to work with the TC.

The bigger difference you have between the input speed of your TC and its output speed the more torque multiplication you have. Cruising at highway speeds there is very little difference and its almost 1:1.

However my problem is that its locking up too soon. Its locking up when I'm pulling a steep grade, pulling a heavy load at the throttle is near 100%. When it locks up I get about a 400-500 drop in rpm, a loss of torque and a shudder.

I still think its weird to have a TC lockup in third pulling a heavy load...

rammike

It's especially handy when you want to tow at less than highway speeds, the 5 miles to my home from the highway is rough and curvey, 40-45 mph max when towing 10,000 lbs., I want it lock-up and in 3rd !

RAM2940

I just had a DTT torque converter and valvebody installed about three weeks ago by TRE Diesel and was told to change fluild after 1000 miles of operation. Also if you are running dextron 3 this could be the reason for the shudder. I was going to call to see what trans fluid they recommend. In there paperwork it says ATF-3 but most run dextron 3 if shudder isn't bad.

Fishin2Deep4U

The DTT VB and TC would be matched.

If lockup is happening too soon, you can lower the APPS voltage and it will bring in lockup a bit later. You might also call DTT and tell them about the issue. It may be as simple as a cable adjustment.

Fluid can cause shudder as well. I run straight Dexron in my DTT and if I get a little shudder I just add a bottle of Lubegaurd.

I have run ATF+3 with no shudder, but I felt that I may be putting in too many friction modifiers for my setup.

So, if you have not done the initial fluid change, try the dexron/ Lubegaurd setup. If that fixes the issue, then it's just a fluid issue. I would not add the Lubegaurd without knowing exactly what fluid and additives are in the trans currently.


Dave

cLAYH

I'm running ATF+3. Half from NAPA half right from the dealer. Needed about 14L with the deep pan and NAPA didn't stock enough!

jester1542

I've heard some reports of tranny shudder if the fluid is low. If yours was a bit low and you were on a steep hill you may have lost enough fluid to have a pressure drop.

cLAYH

I checked it before leaving at topped it up. Plus with the deep pan it would have to be REALLY low to affect performance.

cLAYH

Talked to DTT today but unfortunatly Bill was out. The girl that ansewered said to add a bottle of red lube guard. I told her I was running ATF+3(she was quite surprised!) but said to try adding it anyway.

Any comments on adding the lube guard to a tranny already running ATF+3?

Fishin2Deep4U

Actually, that's not true.

The deep pan in itself does not change the level the pickup is at. So, if the pickup has not been lowered, the same level of fluid is required just like stock.

In other words, being half a quart low with an oversize pan is exactly the same as with the stock pan.

Dave

cLAYH

The pan comes with an extension for the pickup.....