Problems going forward in 2004R

redhotrod

Turbo Happy
Joined
Nov 19, 2002
What should I be looking for if my transmission only moves forward with lots of throttle (more TV I'm guessing) Reverse is great. Neutral is fine. Park works really good. I did drop the pan and cleaned the valve body thinking of a stuck valve, but I still have the same problem...
This transmission worked great a week ago, a few days ago I backed the car out of the garage, and when I went to pull it back in, it took a lot of throttle to move forward. Same thing after the valve body rebuild.


I just got a 300 psi gauge, I can give you guys numbers soon if really needed. And yeah, the Dexron VI is all the way up to full on the dipstick.
 
As you surmised, checking line pressures is the next logical step. If those check out, you may have an issue with the forward clutch pack. Does it make any difference to pull the shifter all the way back to manual low?
 
Unfortunately no, low doesn't change anything. It does however seem to work good in all forward gears with the rear tires off the ground.
 
Forward clutch needed for forward gears. There is your problem.

Posted from the TurboBuick.Com mobile app
 
I agree with forward clutch but it's unusual to have it just go bad.
 
I will get some pressure numbers this evening. Yeah. Hope it's not the forward clutch pack. I just had it ripped down to replace the forward clutches from a previous failure a month ago, a 5k rpm bad shift to reverse will weld them together. Upon the rebuild test drive, it ran and shifted like a bat out of hell.
 
Ok, pressure readings recorded but they are not matching up to the ATSG book. I have a 1 minute youtube video uploading to show how it fluctuates. Looks weird, but my first time checking pressures.
Here are the readings once they steadied out. All readings taken at idle of 1000 rpms with brake on.

Full TV --- Min TV
P 230 PSI --- 70
R 180 --- 75
N 280 --- 70
OD 225 --- 60
D 225 --- 80
2 80 --- 80
1 80 --- 80

This trans has the transgo HD2 shift kit and a superior super servo, wide alto band, blue clutches, bigger boost valve, deep pan, 700r4 filter.

Here is the video


Whats going on???
 
Something isn't holding pressure in low. Seal blow out? Making good pressure in the upper gears. Maybe a shaft Teflon letting pressure out. Is have to look at a diagram. I'm sure one of the gurus will know right off.

Posted from the TurboBuick.Com mobile app
 
Probably transfer tube blow out or clip not installed. Drive pressure is fine. Back to forward clutch again.

Posted from the TurboBuick.Com mobile app
 
Got the trans ripped down again, good call guys on the forward clutch pack. You know how the ATSG book hounds you on be sure to use the right lip seals on the forward and directs and don't mix up the fourth clutch, well..... the piston felt really loose coming out this go around. Much looser now than when I first installed it.
So I am digging through all the lip seals in my kit and I have like 7 or 8 that really look similar, too similar I really not seeing a difference, what is the dimensions or something to identify the right forward piston lip seal? The book seems pretty vague to me.
 
Well I figured it out after staring at these seals for a while,,, they actually have small part numbers molded into the actual lip seal. I could take that number and cross reference it to this sheet.

Can find more part numbers for the 2004r here. http://www.jpat.co.uk/04 GM2 200 200C.pdf
Seals.JPG
 
Top