4r100 Excessive line pressure!!

Hey guys,
Welly son has a 2002 excursion that he has invested over 25k in over the last 5 yrs or so..lift kit tires,rims etc etc..he calls me one day and says he has blown his trans..we pull it, I tear it down order all the parts it needs including a billet converter hi-performance clutches,all new final drive unit including new planets,all new bushings everything plus a TRANSGO TUGGER KIT..put it in and had immediate codes and problems..and a front pump leak..pull it back out reseal the pump thinking I did something wrong although I couldn't find anything wrong..go thru the valve body again put it back in and now I have extreme late shifts 1-2 2-3
And no 3-4...and the front pump is leaking again so I put a gauge on it..it's supposed to be about 50 psi at idle in park..it's around 90..rev it up it pegs the gauge at 275 and in reverse it blew my gauge apart so I don't know how high it went but the gauge maxed out at 500 psi..pulled it out bought a new pump put the TUGGER pressure regulator in it put it back in the truck..same thing..extreme high line pressure..max rpm shifts and front pump leaking..oh and codes for shift errors on the 1-2 2-3 and the 3-4 but it still won't go into 4th
Any thoughts would be greatly appreciated..my son is about to lose his mind over this truck!!

What are all of the codes that are in the PCM? Code numbers, not descriptions.

I would suspect a problem with the installation of the shift kit, or a stuck/misassembled main regulator valve,

Ditto on the valve body kit being an issue, is this the tugger 2 kit? with the separator plate? Like maybe the plate is wrong.

Or maybe a stuck valve in the valve body somewhere.

Mark Kovalsky said:

What are all of the codes that are in the PCM? Code numbers, not descriptions.

I would suspect a problem with the installation of the shift kit, or a stuck/misassembled main regulator valve,

Click to expand...

Damn good to see you here sir!!

Any issues removing/installing valving in the valve body?

When I did mine the bores were so bad I had to file them down to get old out/new in.. I had tonaoend a few hours going through almost all the ports..

Mark Kovalsky said:

What are all of the codes that are in the PCM? Code numbers, not descriptions.

I would suspect a problem with the installation of the shift kit, or a stuck/misassembled main regulator valve,

Click to expand...

Hey mark thanks for the reply and sorry for the delayed reply on my end I have been out of town on business,any way his truck is in Mich and I am in Ga,I don't remember the code #s just that the description was 1-2 shift fault, 2-3 shift fault and 3-4 shift fault, my thing is that I have very seen one with line pressure that high,I've pulled the trans 3 times and went thru it and can't find anything wrong..it's not burning the clutches at all, air checked everything,the trans worked great for him for 5 yrs and then he went to pull a friend out of the mud and smoked it,pulled it found out it was a 10 yr old jasper reman unit bushing were all worn out planets were worn out and all the clutches were fried except reverse,bought a transtar kit w/upgraded clutches and a TRANSGO TUGGER 2 kit, whole new final drive kit with six pinion planets and bushing kit,valve body plate was good,I've built a couple dozen E4ODs and 4R100s over the yrs ( I have been a GM TRANS TECH for 38 yrs)most with a Tugger kit..almost no problems, I fly across the country to fix my son's and everything goes wrong..any way I replaced the pump..the only thing I did was install the tugger pressure regulator into the new pump..but it was a easy install everything went fine,went back thru the valve body again..everything seems normal but I can't get the line pressure down and it keeps shifting late and hard with no 3-4 and then starts leaking out the front..can it be electrical some how..?? Thanks for any advise

DEEZUZ said:

Any issues removing/installing valving in the valve body?

When I did mine the bores were so bad I had to file them down to get old out/new in.. I had tonaoend a few hours going through almost all the ports..

Click to expand...

Sorry for the delayed response, no the valve notes were really clean,didn't see anything wrong with the valve body at all,and the plate was perfect...only put the TUGGER 2 in it because he has future plans of upgrading the power, it's a 7.3 diesel with 38" tires, completely stock with 250k on the OD..I'm wondering if it can some how be electrical...

We need the code numbers.

bowtieguy069 said:

Hey guys,
Welly son has a 2002 excursion that he has invested over 25k in over the last 5 yrs or so..lift kit tires,rims etc etc..he calls me one day and says he has blown his trans..we pull it, I tear it down order all the parts it needs including a billet converter hi-performance clutches,all new final drive unit including new planets,all new bushings everything plus a TRANSGO TUGGER KIT..put it in and had immediate codes and problems..and a front pump leak..pull it back out reseal the pump thinking I did something wrong although I couldn't find anything wrong..go thru the valve body again put it back in and now I have extreme late shifts 1-2 2-3
And no 3-4...and the front pump is leaking again so I put a gauge on it..it's supposed to be about 50 psi at idle in park..it's around 90..rev it up it pegs the gauge at 275 and in reverse it blew my gauge apart so I don't know how high it went but the gauge maxed out at 500 psi..pulled it out bought a new pump put the TUGGER pressure regulator in it put it back in the truck..same thing..extreme high line pressure..max rpm shifts and front pump leaking..oh and codes for shift errors on the 1-2 2-3 and the 3-4 but it still won't go into 4th
Any thoughts would be greatly appreciated..my son is about to lose his mind over this truck!!

Click to expand...

Did you ever figure out the cause of the line pressure? I’m having the exact same problem with my 02 excursion. I rebuilt the transmission put the TRANSGO TUGGER 2 in it. The transmission shifts great and works fine but the pressure in park at idle is 375-400psi up my gauge maxes at 400psi. Driving it gets north of 400psi. Reverse idle is 250psi, drive 375-400 then past that if any throttle is given.