700R4 Remanufactured valve body
11-24-2016, 04:44 PM
#1
Racer
Thread Starter
700R4 Remanufactured valve body
So after a bit of investigation it appears my rebuilt tranny was given back with an "inspected" valve body. At this point my troubleshooting points to all my intermittent shifting problems being an issue with the VB. Since reconditioned VB's are available where certain parts are inspected but many are replaced by default I figured I would ask if any of you have used Hughes or Sonnax VB's. To be honest I do not trust the shops here and that is why I am looking to just order one.
11-25-2016, 12:44 PM
#2
Safety Car
What issues are you having ?
And both those companies are good at what they do
And both those companies are good at what they do
11-25-2016, 01:37 PM
#3
Team Owner
I doubt that any 'remanufacturing'/V.B. rebuild shop has the processes necessary to assure the correct valve springs get installed in each unit they build. You would have been better off to rebuild the one you removed. It, at least, had the correct components in it to begin with.
Sorry.
Sorry.
11-25-2016, 03:55 PM
#4
Racer
Thread Starter
So, bit of a long story Going to include it as I know many of the questions that arise. Short version is, trans was rebuilt by local shop 3 months before I purchased car. Per their reply to my question they "cleaned and inspected VB" as part of the rebuild. Prior to rebuild the owner informed me the issue was present. Owner removed VB, cleaned, reinstalled issue gone for about 1000 miles. Following year He rebuilt motor and had tranny rebuilt. Now issue is back. Issue is, INTERMITTENT 2-3 soft shift under moderate to hard acceleration. Usually right away, once it happens it is rare it repeats during that drive cycle. I have checked pressures and they fall within the ranges I have found in various manuals. I have not done a driving pressure test. So my logic is given the previous VB maint and history it's a good bet that is where the issue resides. I am sure the VB has never been remanufactured with new springs, or even a tv valve upgrade. I have the tv cable adjusted properly. Hopefully I communicated all that well. The shop that did the rebuild was not real helpful. Since the rebuild they seem to have gone downhill. If I have to I will yank the tranny, just hoping to avoid that.
11-25-2016, 04:00 PM
#5
Racer
Thread Starter
I doubt that any 'remanufacturing'/V.B. rebuild shop has the processes necessary to assure the correct valve springs get installed in each unit they build. You would have been better off to rebuild the one you removed. It, at least, had the correct components in it to begin with.
Sorry.
Sorry.
11-25-2016, 08:27 PM
#6
Safety Car
Soft shift 2-3 .
I am more inclined to suggest a TV valve sticking slightly. There is an upgrade that should be made with a spring in the TV valve to help prevent it from sticking
I am more inclined to suggest a TV valve sticking slightly. There is an upgrade that should be made with a spring in the TV valve to help prevent it from sticking
11-25-2016, 09:00 PM
#7
Racer
Thread Starter
Yep I thought that too, couple options there. My only doubt on that one was 1-2 and 3-4 shifts are always spot on.
11-25-2016, 11:23 PM
#8
Team Owner
The trans shop owes you a VB repair or a VB swap to fix the problem. You reported this problem way before their 'warranty' ran out and I gather that it was intermittent...but ongoing.
I agree that it could be a 2-3 shift valve that is sticking. But, it could be several other things in that area, also.
If that shop won't help fix THEIR problem, send a complaint to the Better Business Bureau and whoever you think should know. Then, take it to another shop after you've researched that they are reputable.
I agree that it could be a 2-3 shift valve that is sticking. But, it could be several other things in that area, also.
If that shop won't help fix THEIR problem, send a complaint to the Better Business Bureau and whoever you think should know. Then, take it to another shop after you've researched that they are reputable.
11-26-2016, 07:03 AM
#9
Safety Car
Shift speed is done by the governor do the TV valve upgrade and see how it works out
Last edited by diehrd; 11-26-2016 at 09:42 AM.
11-26-2016, 09:36 AM
#10
Team Owner
OP indicated that shift speeds were fine in the other ranges....not a governor problem.
11-26-2016, 09:41 AM
#11
Safety Car
12-02-2016, 12:22 AM
#12
Racer
Thread Starter
Ok so just to give some info in case others experience similar issues. Valve body out and inspected. It had a TransGo kit installed. Has the TV upgrade with springs and new valve. Everything looked good including plunger travel.
The 2/3 shift valve body was drilled per transgo instructions and there was some stickiness to valve movement. I removed components and took emery cloth and cleaned up what appeared to be some burrs from the drilling process.
Next I wrote sonnax and they responded. Kudos to their tech dept. Did not try and sell me anything, in fact suggested looking elsewhere than VB too unless separator plate was cross leaking. The plate appears worn in 2 check ball areas. Will lod pics in another post to see what you guys think. Sonnax suggested replacing 3rd gear accumulator OE check valve. Often gets missed in rebuilds. cheap part. $12-16 and can be done while in car. So thats my next step. Cant test line pressure as snow is on the ground so once I get this done I'm in for a several month wait to see if it fixes the 2-3 shift flare.
The 2/3 shift valve body was drilled per transgo instructions and there was some stickiness to valve movement. I removed components and took emery cloth and cleaned up what appeared to be some burrs from the drilling process.
Next I wrote sonnax and they responded. Kudos to their tech dept. Did not try and sell me anything, in fact suggested looking elsewhere than VB too unless separator plate was cross leaking. The plate appears worn in 2 check ball areas. Will lod pics in another post to see what you guys think. Sonnax suggested replacing 3rd gear accumulator OE check valve. Often gets missed in rebuilds. cheap part. $12-16 and can be done while in car. So thats my next step. Cant test line pressure as snow is on the ground so once I get this done I'm in for a several month wait to see if it fixes the 2-3 shift flare.
12-03-2016, 12:23 AM
#14
Team Owner
If those holes with the 'teardrop' shape have check ***** seating in them, the plate is no good. Those ***** will leak via that teardrop shaped area and not seal well. If they do not have check ***** sealing in those holes, they are 'no big deal'.
Be careful how you knock off burrs on valve edges/grooves. While they can't have any burrs or projections that cause sticking, the edges of valve lands MUST be sharp, so that there is little leakage past the leading edges. If you roll over those edges, the valves won't operate as well. (Just for your info). Light crocus cloth to feel or remove protrusions/burrs is OK; rounding the edges much at all, is not.
Diehard:
You stated that "shift speed is done by the governor"; and that's not all of the story. The governor generates governor pressure which is used (along with the shift valves, etc) to regulate shifts. The governor can be altered to raise or lower that 'across-the-board' shifting strategy. But, the shift valves have spring rates that individually modify those specific shift points. So, governor pressure alone does not set the shift points for the various ranges. I thought the OP should know the complete story on shift point control.
Be careful how you knock off burrs on valve edges/grooves. While they can't have any burrs or projections that cause sticking, the edges of valve lands MUST be sharp, so that there is little leakage past the leading edges. If you roll over those edges, the valves won't operate as well. (Just for your info). Light crocus cloth to feel or remove protrusions/burrs is OK; rounding the edges much at all, is not.
Diehard:
You stated that "shift speed is done by the governor"; and that's not all of the story. The governor generates governor pressure which is used (along with the shift valves, etc) to regulate shifts. The governor can be altered to raise or lower that 'across-the-board' shifting strategy. But, the shift valves have spring rates that individually modify those specific shift points. So, governor pressure alone does not set the shift points for the various ranges. I thought the OP should know the complete story on shift point control.
12-03-2016, 12:29 AM
#15
Racer
Thread Starter
If those holes with the 'teardrop' shape have check ***** seating in them, the plate is no good. Those ***** will leak via that teardrop shaped area and not seal well. If they do not have check ***** sealing in those holes, they are 'no big deal'.
Be careful how you knock off burrs on valve edges/grooves. While they can't have any burrs or projections that cause sticking, the edges of valve lands MUST be sharp, so that there is little leakage past the leading edges. If you roll over those edges, the valves won't operate as well. (Just for your info). Light crocus cloth to feel or remove protrusions/burrs is OK; rounding the edges much at all, is not.
Diehard:
You stated that "shift speed is done by the governor"; and that's not all of the story. The governor generates governor pressure which is used (along with the shift valves, etc) to regulate shifts. The governor can be altered to raise or lower that 'across-the-board' shifting strategy. But, the shift valves have spring rates that individually modify those specific shift points. So, governor pressure alone does not set the shift points for the various ranges. I thought the OP should know the complete story on shift point control.
Be careful how you knock off burrs on valve edges/grooves. While they can't have any burrs or projections that cause sticking, the edges of valve lands MUST be sharp, so that there is little leakage past the leading edges. If you roll over those edges, the valves won't operate as well. (Just for your info). Light crocus cloth to feel or remove protrusions/burrs is OK; rounding the edges much at all, is not.
Diehard:
You stated that "shift speed is done by the governor"; and that's not all of the story. The governor generates governor pressure which is used (along with the shift valves, etc) to regulate shifts. The governor can be altered to raise or lower that 'across-the-board' shifting strategy. But, the shift valves have spring rates that individually modify those specific shift points. So, governor pressure alone does not set the shift points for the various ranges. I thought the OP should know the complete story on shift point control.
For the plate thats what I figured. Yes those holes had check *****. Will order a new plate. Odd, the rebuild has very few miles on it. 1000 or less.
12-10-2016, 02:05 AM
#16
Racer
Thread Starter
Wanted to update and once I take it apart, will add pics in case anyone else has the problem. I called Dana @Probuilt. Nice guy. Anyway, he is putting together a couple parts and believes a new plate and the simple mods he will detail will not only fix the issue but make the transmission function the way I want. He did say the intermittent issue sounded like air was getting into the fluid. We will ensure a corvette servo is indeed in there, if not one will be put in. There are some springs etc he will be sending as well. So hopefully this spring, no more guessing as to whether my 2/3 shift will be solid or not.....
12-11-2016, 12:55 AM
#17
Team Owner
Let us know how it goes... 
12-11-2016, 09:42 PM
#18
Racer
problems with 700R4
starting a new thread here on 700R4. engine is a 408" at 525 hp ,3.55 gears 2500 stall with two problems.the trans shifts at 15mph during regular driving and wot. acceleration shifts 1st to second at 3000rpm then "stack" shifts 2nd,third,fourth.TV cable is pulled tight at idle no slack what so ever.do i first install a performance governor like SBO offers or is there another answer.secondly the trans does downshift manually by pulling back shift lever. i have my son to help me but need direction.disable vet