Transmission Guru's
 

My dad has a 2500 hd 6.0 gas with i think a 4L80E (not positive) that just today started shifting hard. Truck just turned 100,000 miles completely stock. Trans temps looked normal on the gauge, we were just driving normal not towing anything.

The 1-2 shift will make you think the truck has a shift kit, 2-3 isnt quite so bad but its pretty noticeable. Fluid level was checked and to me it looked higher than normal.

There is a check engine light on but i dont have a scanner to check it. I will tomorrow.

Any ideas? PM me if you want.

Thanks

needs a new engine, trans, and transfer case... i dont see any other way to fix it... and to offer what help i can, i will take the stuff you remove to get it out of your way :)








:hide: :hysterical:

sounds like something is not right. i would say it is going full line pressure for some reason. maybe check the front tire pressure to make sure its not making all the fluid run foward if they are low. if thats not the issue i would say time for a new trans!

I knew someone was gonna come with something like that! lol

Thats a good assumption, Actualllly the front tires were flat to the ground when we checked the fluid.....had to let the air out so we could reach the dipstick!











:joke:

Here is an idea! Put the lentech in the 2500 and buy a glide for the stang....

haha, im pretty sure dad doesnt want to manually shift anymore.

A lot of times when a transmission code is set due to an electrical issue in the transmission electronics, the strategy is to go to maximum line pressure as a failsafe to try to keep the trans from self destructing. Chances are, the PCM/TCM has seen an electrical fault of some sort and has flipped to failsafe mode. Shifts will definitely firm up when that happens.

What Gerald said.

Commonly ive seen bad knock sensors play havoc with the hd trucks. But the problem could be any number of electrically related parts. First order of business is to find out what SES code you have.

Thanks guys,

I had the code pulled today and it was a P0894 Trans componet Slipping. We cleared the code and i drove it for about an hour after and it hasnt acted up again, but the temp only got to about 150 where as yesterday it happened @ 170*.

And according to the trans pan its a 4L80 it has 17 bolts.

Is this something easy to fix or is he looking at an entire overhaul?

Thanks

tow/haul button pushed?

No, the tow haul is off.

I drove the truck to work tonight and after about 15 miles it started shifting hard again. Trans temp was still about 150*. The check engine light hasn't come back on yet.

With that code and 100,000 miles, it could very well be time to open it up.

Thanks, Ill see what he wants to do with it.

The lock up clutch is slipping. The computer will watch as the RPMs are too high after lock up is commanded. Clearing the code will like you found out put everything back to normal until the computer sees the problem enough times to set the code. Also that code may not illuminate the SES light.

If he isnt ready to rebuild the trans, id start with the valvebody and solenoid. Easy to get to. If that doesnt work then youd have to pull out the trans, you could gamble on a new torque converter, or just go ahead with the rebuild and replace the converter along with the fresh trans.

Thanks Rob,

Anything special about pulling the valve body off? Am i looking for worn o-rings/pluggage?

Im sure he doesnt want to rebuild it just yet so ill try this first.

vb is pretty simple, the check balls will fall out but I have plenty of diagrams for the locations and a little petroleum jelly will stick them back into place. The vb will come down complete, no spring flying around. Ill try and send you a couple diagrams with the problem areas today.

Awesome Thanks!