Th200r4 first to second shift problem
Thread Starter
Instructor
Joined: Sep 2007
Posts: 218
Likes: 7
From: Tonbridge, Kent
Th200r4 first to second shift problem
Hi folks, been a while since I lasted posted!
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
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
Thread Starter
Instructor
Joined: Sep 2007
Posts: 218
Likes: 7
From: Tonbridge, Kent
Hi, I checked the governor when I dropped the sump two weeks ago. There was no debris in the pan, i changed the filter and took the governor apart and all was working fine before and after I cleaned it up, and seals were good!
I thought a governor problem would create problems in all gears not just first to second?
I thought a governor problem would create problems in all gears not just first to second?
Last edited by knodty; Aug 23, 2013 at 05:53 AM.
Intermediate
Joined: Jul 2013
Posts: 42
Likes: 0
From: Mooresville North Carolina
I think you have a valve body issue. The TV cable will affect the pressure,the governor affects the timing. If the other gears are correct after 1-2 shift out the governor should be O.K. Having said that the only way to know is put a gauge on the governor port and check it. The hard shift is caused but the throttle pressure going high due to the late shift out. Have the governor pressure checked and if it's good the 1-2 shift late is in the valve body.
Thread Starter
Instructor
Joined: Sep 2007
Posts: 218
Likes: 7
From: Tonbridge, Kent
Hi, where do i check governor pressures from, is it the same port i check tv pressures from? and i take it it must be checked whilst driving the car, in all gears or just in drive? im a little green on this one! Trying to save myself some $$
Cheers
Cheers
Intermediate
Joined: Jul 2013
Posts: 42
Likes: 0
From: Mooresville North Carolina
Your right the TV pressure affects the shift point, TV pressure vs. Governor to decide the shift point. But he is saying he tested the TV pressure and it's good, so that leaves low Governor pressure or valve body as possible causes. This unit unfortunately does not have a governor test port I thought it did. It does have a 1-2 shift valve port but I can't seem to find a pressure spec for it.
http://forums.corvetteforum.com/tags/200r4-page3.html
There is lots of information in these threads. I'll keep searching for the spec. for 1-2 shift valve.
http://forums.corvetteforum.com/tags/200r4-page3.html
There is lots of information in these threads. I'll keep searching for the spec. for 1-2 shift valve.
Thread Starter
Instructor
Joined: Sep 2007
Posts: 218
Likes: 7
From: Tonbridge, Kent
But I would of thought if there was a problem with the tv cable or the governor it would be the same in every gear change not just 1-2 change, which says to me that it is related to what ever allows the trans to change from 1-2.
2-3 & 3-4 up an down changes are all good at all revs/speeds above 45-50mph ish loads etc.
So what is it that releases or engages to allow it to change from 1-2? Surely it cannot be the tv cable or governor, is there not a specific oil way that might be leaking to cause this?
2-3 & 3-4 up an down changes are all good at all revs/speeds above 45-50mph ish loads etc.
So what is it that releases or engages to allow it to change from 1-2? Surely it cannot be the tv cable or governor, is there not a specific oil way that might be leaking to cause this?
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Melting Slicks
Joined: Oct 2006
Posts: 2,417
Likes: 336
From: Texas
you might be able to find more insight on this site, its mainly for the 200-4r.
http://www.turbobuick.com/forums/for...ssion-talk.12/
http://www.turbobuick.com/forums/for...ssion-talk.12/
