Th200r4 first to second shift problem

[Knodty]

Hi folks, been advised to come here from the corvette forum to see if you can hel me
After having a trans cooler hose blow off on my BTOVERDRIVES LEVEL 3 th200r4 on a parade lap of the track back in sept last year. I repaired the hose, and topped up the fluid. I noticed it was not changing from first to second until above 4,500rpm and only if i back off the throttle! 2nd to 3rd and 3rd to 4th changes are fine under light or hard throttle!
It does drop into 1st when it shouldn't at about 35mph but will not go up to 2nd until I back off the throttle.
The atsg manual points me in the direction of the valve body gaskets either side of the spacer plate? I've checked the Tv cable and pressures and governor all seem to be working fine with an idle pressure of 80-85psi and a full throttle of 240psi when the tv cable is pulled right out
Any input will be greatly appreciated.
Cheers
Peter
Was going to post a link to the thread there but apparently I cant
Cheers

 

[77 cruiser]

Did you check to see if the gov. spring was still in place?

 

[Knodty]

Yes I did take it out clean it up, check seals etc, change fluid and filter and tv cable operation, and all seem fine!

 

[Knodty]

:-(

 

[TexasT]

Did you check pressures in all the shifter positions?
Did you drop the valve body and see about the gaskets as you noted in your original posts?
Fluid still looks cherry red?



Posted from the TurboBuick.Com mobile app

 

[flamed86gn]

Sounds like your second gear band is on its way out if it isn't already!


Posted from the TurboBuick.Com mobile app

 

[Knodty]

Hi,
I haven't taken valve body off yet or check the pressures in all gears just in park, as I'm a little apprehensive of tackling these transmission as it is a bit of a dark art to me, don't want to cause more damage than I have at the moment.

Do I have to have the car driving on the road under load or will jack stands be ok?

When I dropped the pan there was no particals in the fluid and it was cherry red still! When I accelerate hard there doesnt seem to be any slipping at all, and would thought that might be obvious if the bands were on their way out as I'm putting out over 400lbft of torque in a 460 cuin motor! But I'm no expert that's why I'm here to ask you guys!

Cheers guys

 

[TexasT]

If you decide to tackle get a copy of the ck manual and a atra rebuild manual for reference. Not hard but attention to detail is very important.

Is put it on jack stands and do it that way. You can check pressures easier that way.

Sent from my HTC PH39100 using TurboBuick Mobile mobile app

 

[Knodty]

I have a ATSG manual, I thought they were highly respected as rebuild manuals, are they ok?
I'll get back to you and let you know how I get on!

Cheers thanks for your help

 

[TexasT]

That's the one, blue n white cover. Specs and how to. The ck just goes into much deeper how to.

Posted from the TurboBuick.Com mobile app

 

[Two T's]

Happened to me one time no line blown off but the first to second shift the same exactly. And my problem ended up being the converter. Mabe when line blew converter got hot. Just my 2cents hope you find out your problem.

 

[Knodty]

Hi guys,
Been a while now but I connected the pressure gauge and took pressure readings in gears!

1st max pressure 150lbs
2nd max pressure 190lbs
3rd max pressure 190lbs and
4th max pressure was 190lbs.

I've/we've a friend an me, removed the valve body and cleaned up everything by stripping it apart and only seemed to find a bit of a problem with the middle set of valves which were the 1-2 shift valves as they were a bit stuck in there!
But put it all back together new fluid/filter and still the same characteristics, no shift from 1st to 2nd until I back off the throttle.
I did not have the gauge hooked up this time as I thought it would of been sorted!
Any help appreciated guys.

 

[TexasT]

If those valves aren't free, i can see that as a problem. They might need to be "shined" up a bit as they might be scuffed and not able to move freely in the bore. Shine the bore up too, but not so much that it leaks a lot of fluid due to a lot of clearance.

 

[Knodty]

Everything was all freed up when we put all the valves back in the body and I see no reason why it would not work!
What would cause the different pressure on on 1st gear as to all others?
Cheers
Peter

 

[Knodty]

Everything was all freed up when we put all the valves back in the body and I see no reason why it would not work!
What would cause the different pressure on on 1st gear as to all others?
Cheers
Peter

 

[Knodty]

What would cause the different pressure on on 1st gear as to all others?
Cheers guys

 

[bison]

The pressures are too low for max tv for a turbo regal. The only thing holding in 1st is the forward clutch and roller clutch. When it shifts to second it applies the band and does nothing else. What about low 1?

 

[Knodty]

The pressures in low 1 are the same @ 150psi.
BTW This trans is fitted to a BB Vette. And is a BT Overdrives trans level 3 with a 2400 stall converter.
Peter

 

[David Husek]

What is the line pressure at idle in all shift detents? What is the part throtlle while cruising pressure?

 

[Knodty]

Line pressure at idle in all gears is 75psi
And at part throttle cruising it is 100psi