Unhappy with my auto tranny

[BIG DOOLIE6.5]

I have a '97 3500 dually with an automatic tranny. There is nothing majorly wrong with it but i've noticed it will sometimes slip at high speeds (when I'm blowing a cloud of smoke in the face of my buddies Power Joke goin' down the free way). I was just wondering what parts I would need to swap over to a standard tranny, and if it would be worth the aggravation and cash to do so. Any help or comments are appreciated.:)

[njdevi11]

Probably is going to be really expensive, the flywheel's for the 6.5 runs like $500 alone from GM. An nv4500 is around $1g and then you will have to find the right adapter for the trans-to t-case.

If i had to do it, i would find an sm-465 and a np205 and convert to a front dana 60 straight axle at the same time.

You could always put a manual shift kit in from transgo.

I'm in the process of collecting parts to swap my CJ from a th400 to an sm465. Its running me around $1200 so far. Thats with a flywheel/trans/np205/clutchkit/pedals/master/slave and I still need a new yoke for the rear output or my rear axle/and new driveshaft. It's a project thats very involved and not for the novice.

[TedReminder]

If it slips, there is indeed something wrong with it.
Ted

[keplinger78]

If it slips, there is indeed something wrong with it.
Ted
If it's slipping..bad news...Here's what was up with my 93,Overdrive would work till the truck warmed up,then start slipping.The guy that rebuilt the tranny had this to say. The solenoid that tells it to shift into overdrive went bad.That caused to much pressure and cracked the piston that holds force against the overdrive clutch packs.The tranny had less than 15k it was a GM replacement.He tested the solenoids and they tested OK,then not,then OK..Just depended which way he was looking at them...LOL So you might put new solenoids in the tranny and see if that helps but don't get them from GM.

Good Luck,
Tom K.

P.S. It cost $1800 to have mine fixed...new HD cooler,HD converter,shiftkit,u-joints....

[primerk5]

I have a '97 3500 dually with an automatic tranny. There is nothing majorly wrong with it but i've noticed it will sometimes slip at high speeds (when I'm blowing a cloud of smoke in the face of my buddies Power Joke goin' down the free way). I was just wondering what parts I would need to swap over to a standard tranny, and if it would be worth the aggravation and cash to do so. Any help or comments are appreciated.:)
Switching to a Stick will be a chore and cost a good deal of money. I actually have a Standard 5 speed that I may someday put in my truck. Unforunatly it needs rebuilt and it looks as though the parts alone may be around 800 bucks. My only issue for this is that the engine Management system is designed for a Automatic. It functions differently when you let off the throttle at different speeds. To do it right I would think you would need a Stick ECU, maybe even wiring. Though you could make yours work. Pedal assemblys slave cylinders would also be needed. If your truck is a 4x4 the transfer case should work. (I'm not quite sure about that though) 80's trucks with 4 speeds or auto's t-cases can't be swaped. Might be the same for later bodystyles. I'm sure you could run the stock Auto ECU and make it work. It may be a hinderence on the engine.

Anythings possible. I work with hondas. If you don't use the right ECU things won't work right. In older V8 TPI camaros you could have the Prom/ECU Chip Modified to show it was a Stick. It may be possible to do this in these vehicles.

[sixnickel]

Why do you say it's slipping?? These electronic controlled transmissions know when they are slipping. They will set a DTC and go into limp in mode and boost up the line pressure to save it's self. Maybe all you are feeling is the converter unlocking as you are pushing on it and the torque converter is doing it's thing!! Just a thought!!

[Bob Bateman]

Most of the complaints I get at my shop is slipping in the higher gears with the 4L80E. What most people conceive as slipping is the PWM (pulse width modulated) converter. I would check the transmission for codes and take a test drive with my local transmission rebuilder and see what the scanner shows under actual conditions. These units are designed to slip the TCC application. Look for more than 200 rpm difference between 4th gear and converter slip. If that is the case it should have a code and harsh shifts after a 10 mile test run. This will be due to the computer commanding max line pressure to keep the unit from burning up, also putting it into limp in mode. (2nd and 3rd gears only.)

Hope this helps!
Bob