Chuy79

Ok long story short .. i bought a 4l80e 2002 model i did a hd2 shift kit in it and replaced all seals on the outside of it to prevent future leaks. So far it all looks good all gears shift well to include the lock up over drive but when i try to take off from a stop it goes but it begins to slip then grip then slip again sorta like the rear of my truck jumps or thumps when its happening. I checked my pressure via a gauge and whith the mod connector off i get around 220 in reverse and like 140-150 in drive... its that what its sopposed to be ? Oh and by the way the pump is making a slight whining noise when in park or nuetral as well .... i thought it was possibly a clogged filter so i replaced it with a filter from the deakeeship but it dudnt change nothing all fluid are full and did get vibrating from the gauge needle as well as a vibration from the gauge hose almost as if the pump was being starved of tranny fluid can any one chime in thanks in advance. Btw the engine is a 6.0 engine ...... also i took the valvebody off and i saw a check ball seat in the tranny casing a little worn will that have an effect on pressure or should i just replace the tranny pump

MaroonMonsterLS1

low fluid
Did you verify dipstick level? I doubt it

150 in drive is typical with an HD2 and a stock trans

Checkball in the case always look beat up. It's OK

I bet 2 or 3 qts of fluid fixes your issue

Chuy79

Yes the oil level is good i double checked to make sure it was as far low pressure i read somewhere that if i disconected the transmission connector that the tranny would go to limp mode making the pressure over 200 both reverse and drive am i missing something right

Chuy79

Also forgot to add the gauge needle fluctuates from like 90 to 150 in idle is that normal ? Shouldnt it be somewhat steady ?

MaroonMonsterLS1

When I say verify dipstick level...I mean take the pan off, check where the "full" mark is on the dipstick...make sure that "full" mark is level with the pan gasket sealing surface of the case
I don't mean just looking at the stick

All of your symptoms are either a pump that is very clapped out...or low fluid level.
The fluctuation is from cavitation because the pickup is sucking air/foam

Dump 2 or 3 qts in even tho the dipstick currently shows full...and if things get better...you know you need to drop the pan and inspect the filter and inspect the dipstick level

Chuy79

Thanks again for the information i went ahead and dropped the pan to make sure the dipstick was level with the pan gasket and it looks like its roughly 1 inch just above the hot on the dipstick i also replaced the force motor and i inspected the filter and the rubber seal that goes on the casing all looks good the only think i saw was on the oil pan ... it has minor gray sludge im guessing that normal since it was slipping when i would try to power brake . I went ahead and installed the pan filled it up to the new full location on dipstick, 1 inch above the full mark, and test drove it but it continued to slip when i would try to burn tire so i decided to drop the tranny ... took the pump off and i inspected the foward clutches and the clutches just behind those they all look good. As for the pump the gears do seem a little scored especially the smaller gear nothing major but it clearly visible so i purchased a new pump and i will be installing it this week hopefully things will work

Chuy79

One more thing i forgot to add.... when i shift into any gear it starts at 0 and then itll start to climb to 50-60 at idle in gear . Im assuming it should go to 50-60 as soon as i place it into gear

MaroonMonsterLS1

It's good you found the dipstick being off. That isn't atypical from what I see alot of times even with factory sticks

As far as slipping when you try to power brake...what exactly do you mean? If you're power braking...you aren't moving...why do you think anything is slipping?
As far as pressure, how long does it sit at "0" before climbing?
A quick dip is normal. The passages and piston needs time to fill
A dip to - that Immediately recovers woulnd't worry me if you're just "parking lot" shifting it sitting still

Chuy79

Power brake i mean to press the brake and give it some gas in an effort to spin the wheels except i hear it slipping also while taking off from a stand still itll go but then itll start to slip then grip then slip again at the same time i can feel the tires chirp once it grips again its almost as if the pressure goes up thats when it grips then the pressure go low thats when it slips it only does this when trying to get up and go otherwise normal driving is flawless all shifts work and they are smooth
as for the 0 pressure while changing gears it dips to zero then it climbs to 50 or so roughly in 3 seconds itll climb to 50 or so while parked in the parking lot

Chuy79

Also if it makes any difference im using synthetic tranny fluid not the standard dexlll i heard that using synthetic could cause slipping

this is a 2002 4l80e