1 - 2 shift weak ?

DorianL

Member
:( Haven't quite figured this out yet...


P: 110 - 260
R: 170 - 260
N: 110 - 230
D: 110 - 240
3: 110 - 250
2: 250 - 250
1: 250 - 250

+ PTS pressure regulator + PTS shift kit + used GN servo + 2200 HD converter... behind a torquey 400 SBC. The TV cable is on the tighter side. I added about 1/2 inch over the full mark (on a lokar dipstick).

If I bring the RPM up slowly the shifts are hard. Once I bring in some power the 1 - 2 goes flat/flares.

It usually hits hard(er) when I slack off the gas.

I can't manage to chirp the tires with this thing. I think the same happens with the other gears... apply power and it flares. If I creep up on 3 - 4, even that shift is kinda strong.

Could it be I am cavitating ? This happens even on quite weak acceleration. Maybe my fluid level is low ? (I remember during the pressure test N and P would drop if I stayed more than a few seconds there - low fluid ?)

Should I test drive with the pressure gauge fitted ?

Any clue ? I guess try again with an extra quart of fluid ?

D.

EDIT - could the band be slightly toasted ? But then it would not be firm at even low power, right? This must be a cavitation problem.

HELP - gentlemen. Third is the time for this trans to go back in - let's make it a charm !
 
Hmmm, been examining other posts.

I'm beginning to be convinced that this is cavitation. I think I'm going to add another quart to see if that improves things. If so, time for a deep pan.

The thing is, this flaring occurs at very mild throttle. Maybr the lokar dipstick is reading higher than it acutally is ?

Any thoughts ?

D.
 
I`d take a run with the guage on it that will tell you if it's cavitation. Should only blip the guage when it shifts.

Jim
 
Will do !

Thanks :)

Any particular way I should test drive ? Just a small round the block to figure if this is the problem ?
 
update

I did both - i.e. I added another quart and hooked up a pressure gauge and took for a drive.

The behavior seems to be the same. Firmer shifts at low throttle, flaring a more throttle. Slacking off the gas at the right time gives a firm shift.

At idle in N I get 150 psi at 1000 RPM
At idle in D I get 130 psi at 900 RPM

In P and N I hear a whirring sound from trans - sucking air :confused: Pressure gauge needle shaking +/-10 psi. I hear this whirring when cruising.

When driving from a full stop I have 130 - 150 PSI. Give some gas and the pressure climbs to 200 and, as accelerating, it drops to 150 then shifts at 2200 rpm with a small blip on the needle. Shift is on the firmer side if I stay out of the gas. If I give more power - the pressure tends to remain at 150 and the shifting flares.

Cruising is around 150 psi.

Me thinks I'm sucking air. Or the level is still low. $%@#$% Lokar dipstick. The dipstick is tough to read but, since I replaced the pump I put 10.5 quarts in there - is that enough. It reads high on the dipstick - one inch over the Full mark.

Any thoughts ?
 
When you put the filter on did you put the little tab that's attched to the VB bolt on top of the filter so it is pushing it to the bottom of the pan?

Jim
 
Hmmmm

the clip is definitely not holding it up, but I'm not sure it is pressing it down either.

Think I might try an extra quart.
 
Now I'm wondering if I did that with my tranny filter, my tranny does the exact same thing as the one described, and now that I think about it I think I clipped my filter up! Do remember the filter seemed like it was too loose unless it was pressed way up in there, is that normal? I'm gonna be checking out my tranny before I drive it anymore anyhow, so I'll investigate. Any links to pics that show how the filter should look in there?
 
Re: Hmmm, been examining other posts.

Originally posted by DorianL
I'm beginning to be convinced that this is cavitation. I think I'm going to add another quart to see if that improves things. If so, time for a deep pan.

The thing is, this flaring occurs at very mild throttle. Maybr the lokar dipstick is reading higher than it acutally is ?

Any thoughts ?

D.


I'm having the same problem only I referred to it as "short shifting"on the 1-2 shift, seems there is a slight flare then it grabs and goes, plus it shifts way below the redline!! one other thing-it makes a sound similar to an aftermarket wastegate bleeding of boost during the shift!

I added a deep pan with the bottom feed filter and it still does the same thing, so its my opinion that its not the filter or fluid.

Please let me know if you find the "cure" for it.

HellOnWheels
 
will do.

According to Bruce, I am probably 4 quarts low. I will try that in a day or so. The dipstick is marking high because of foaming it seems.
 
I added 2 quarts

Did not help - the shifting behaved the same.

I belched out the extra fluid - got on some hot parts and I offered an impressive smoke show to the local fauna here in Belgium. :D

I heard a whirring sound from the trans I think I could feel it in my feet too - My guess is that it is the pick up the is sucking air, or the pump is bad.

D.
 
Back
Top