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Re: 1992 V6sei auto gearbox repair

Posted: Sun Mar 03, 2019 8:48 pm
by MTXM
Thanks Mike and in the meantime I have pulled and thoroughly stripped the valve block and I did find a couple of issues. The most significant discovery was that the 2/4" Band (C') Accumulator Valve appears to be jammed, although I am not sure what the function of the valve is and whether it might cause loss of all drive. I attach a copy of the relevant diagram and a photo of the valve, which cannot be removed without further dismantling. I also found some minor strands of rubber debris (governor seal?) against the 1-2 Shift Valve against the outer head when removing the cover although the valve appeared free. The next task will be to fit my spare valve block that I have also given a good check over and here's hoping! With regards, Matthew T.

Re: 1992 V6sei auto gearbox repair

Posted: Sun Mar 03, 2019 8:52 pm
by Dieselman
I would strip and clean the valve block you have there first, as you know it has been working for a number of years.
It sounds like you have found the issues...

Don't forget to check the governor seals are intact and there is no further rubber in the governor valves.

Re: 1992 V6sei auto gearbox repair

Posted: Sun Mar 03, 2019 9:03 pm
by MTXM
Many thanks Will and I am inclined to fit the spare valve block as that had been my original plan, hoping changes might be smoother. I am also unsure how to access and free the stuck valve that is retained by an internal clip - perhaps Dean can advise and has photos? I will certainly pull the governor if the issues are not fully resolved, but I swapped the complete governor after the earlier seal failure and the original went onto the cobalt car! With regards, Matthew T.

Re: 1992 V6sei auto gearbox repair

Posted: Sun Mar 03, 2019 10:53 pm
by Dean
The governor is a dead end in the circuit from what i remember, any rubber seal fragments from here would end up in the sump of the box and would have to get past the oil filter which unless damaged is not possible so not sure where they would come from other than O ring seals in the block itself.

The accumulators are just dampers, they soften the increase of pressure and damp out pressure spikes or waves within the circuit so i would guess that is responsible for your harsh engagement or shift, usual failure here is of the spring snapping which completely removes the damping effect of the valve.

if debris of that size has made it into the valve block it could have passed through the shift valves and into the body itself blocking one of the metering discs or oilways. this could result in a loss of drive if it was lodged in the wrong or right place.

I do not recall any valves that were difficult to extract once both end plates were removed.

D

Re: 1992 V6sei auto gearbox repair

Posted: Sun Mar 03, 2019 11:35 pm
by MTXM
Thanks Dean and I have now dismantled the remainder of the valve block, which was necessary to remove and free the stuck valve as the retaining clip is buried inside. I managed just about not to loose any of the tiny metal cups (six in different sizes and positions) and nylon balls (two large and two small) and I think all the parts are refitted correctly. There were a couple of other small slithers of rubber and they may not be from governor seals as you suggest, but also do not look like o rings (I only found one on the 1-2-3 sequence valve). Anyway hopefully the now freely moving stuck valve was the issue! With regards, Matthew T.

Re: 1992 V6sei auto gearbox repair

Posted: Sun Mar 03, 2019 11:42 pm
by Dean
the metering discs and balls can be retained in place by sliding the top section with dividing plate horizontally off of the lower section, turning it over and sliding the plate off of that section, this leaves all metering devices in situ and undisturbed.

Fingers crossed for you but i think the source of this rubber debris needs to be identified if possible.

D

Re: 1992 V6sei auto gearbox repair

Posted: Mon Mar 04, 2019 12:02 am
by MTXM
Unfortunately I did not understand about the order of removal Dean, but I know for next time and luckily collected and relocated all the bits with the help of the manual. The pieces of rubber were very thin flat strips and definitely not gasket compound or sections of o ring, and on reflection also not governor seals given the cross section. If the storm abates I manage to refit the valve block tomorrow! Regards, Matthew T.

Re: 1992 V6sei auto gearbox repair

Posted: Tue Mar 05, 2019 5:13 pm
by MTXM
Well it does not appear to be a valve block issue as I have refitted the item without change, assuming I did a thorough job! I have also spoken to my mechanic and he has advised me to pull the governor next. It was suggested that a defective governor seal can cause loss of all gears and sections of rubber can be circulated all round the box through the oil. The oil was fairly clean apart from very fine residue, although I did notice a few more rectangular slithers of rubber as I found in the valve block. On reflection, the sections of rubber do look quite like pieces of governor seal as the width is roughly similar, assuming the thickness can be stripped away. I wonder if there any other similar seals in the box that could fail and cause loss of all gears? Regards, Matthew T.

Re: 1992 V6sei auto gearbox repair

Posted: Tue Mar 05, 2019 5:16 pm
by MTXM
Just a reminder of what happened to my other governor seal, although the issue was done to my poor fitting! Regards, Matthew T.

Re: 1992 V6sei auto gearbox repair

Posted: Tue Mar 05, 2019 6:38 pm
by MTXM
I have now pulled the governor, which looked fine initially, but then on clse inspection of the inner rubber seal (in poor light) I noticed excessive wear to the surface that hopefully is my problem! The slithers of rubber in the oil certainly could have come from the seal. I attach a photo and will take another in daylight. Regards, Matthew T.