1992 V6sei auto gearbox repair

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MTXM
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Re: 1992 V6sei auto gearbox repair

Post by MTXM » Sat Mar 02, 2019 11:35 pm

I also should have also mentioned that when I dropped the oil I added some Lubeguard protective fluid at the suggestion of my mechanic, although after 200 miles there was no noticeable change to the shifts. It occurs to me that the governor is perhaps unlikely to be the cause of the problem, since broken seals usually cause weird changes rather than no gears at all, although I know reverse can be lost. I will certainly start with the valve block and I wondered about the first and reverse lock up valve. If engagement of first gear was obstructed by the valve block would there be no forward drive at all? Regards, Matthew T.
1989 V6 Exclusive (Poland car) - Now living in a local Motor Museum!
1990 V6sei auto (grey auto)
1990 V6sei manual (gold car)
1990 V6.24 Pallas (Germany car)
1990 V6.24v (Scotland car)
Other previous XM sold and broken too many to mention!

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Dean
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Re: 1992 V6sei auto gearbox repair

Post by Dean » Sat Mar 02, 2019 11:57 pm

So far as i understand the governor cannot stop 1st gear selection, it could prevent or change the shift point of a 1-2/2-3/3-4 shift and prevent reverse engagement but not drop all forward drive. This will most likely be the valves you played with last time in the block or the clutches themselves.

D
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Re: 1992 V6sei auto gearbox repair

Post by MTXM » Sun Mar 03, 2019 7:42 am

Thanks Dean and just to confirm that I have not yet touched this valve block. I agree the governor seems unlikely to be the cause of the problem this tine. Is it really possible all the clutches can fail and then return and then fail again? At the last occasion when I dropped the oil all was clear with no debris, so hopefully that is still the case! Is the failure of the clutches generally down to the plates, since here it feels more like a pressure issue? There is always the pump and t/c, but I am guessing that would involve debris and the former is quite robust as you pointed out before. With regards, Matthew T.
1989 V6 Exclusive (Poland car) - Now living in a local Motor Museum!
1990 V6sei auto (grey auto)
1990 V6sei manual (gold car)
1990 V6.24 Pallas (Germany car)
1990 V6.24v (Scotland car)
Other previous XM sold and broken too many to mention!

xantia_v6
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Re: 1992 V6sei auto gearbox repair

Post by xantia_v6 » Sun Mar 03, 2019 7:47 am

Matt, you don't seem to have told us exactly what the symptoms are this time. Has it lost reverse gear as well as the forward heard?
1999 XM Exclusive V6 24V ES9 Manual (LHD) 105,000 km
1997 Xantia Exclusive V6 (RHD) 45,000 miles

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MTXM
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Re: 1992 V6sei auto gearbox repair

Post by MTXM » Sun Mar 03, 2019 8:44 am

Thank you Mike and I can confirm that I have lost all gears, both forward and reverse! With regards, Matthew T.
1989 V6 Exclusive (Poland car) - Now living in a local Motor Museum!
1990 V6sei auto (grey auto)
1990 V6sei manual (gold car)
1990 V6.24 Pallas (Germany car)
1990 V6.24v (Scotland car)
Other previous XM sold and broken too many to mention!

xantia_v6
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Re: 1992 V6sei auto gearbox repair

Post by xantia_v6 » Sun Mar 03, 2019 8:53 am

A faulty sprag clutch in the torque converter can cause loss of all drive from standstill. Interestingly, if it fails with the car in motion, the torque converter will continue to transmit torque until the speed drops to the point where torque multiplication should start.
1999 XM Exclusive V6 24V ES9 Manual (LHD) 105,000 km
1997 Xantia Exclusive V6 (RHD) 45,000 miles

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Dean
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Re: 1992 V6sei auto gearbox repair

Post by Dean » Sun Mar 03, 2019 9:11 am

Hi Matt

Having lost all drive the first thing i would do is a quick pressure test from the main test port on the front of the box.
Would the sprag clutch's one-way element result in total loss of drive or just a loss of efficiency? i would think there would be some metallic material in the oil if this one-way clutch had failed also.

D
92 Citroen XM Prestige 3.0i Auto R.P5678
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Re: 1992 V6sei auto gearbox repair

Post by MTXM » Sun Mar 03, 2019 9:32 am

On both occasions I lost drive while in motion, with the first after hot running and repeated stop/starts in slow traffic and the second from cold shortly just after pulling away. It may not be significant but the two incidents occurred at relatively low speeds while accelerating. Once again I wonder whether failure of the t/c could be temporary and allow full recovery before failing again and there was no debris in the oil last time. Unfortunately I do not have the facilities to check pressure on the box Dean but I will also speak to my mechanic on Monday. With regards, Matthew T.
1989 V6 Exclusive (Poland car) - Now living in a local Motor Museum!
1990 V6sei auto (grey auto)
1990 V6sei manual (gold car)
1990 V6.24 Pallas (Germany car)
1990 V6.24v (Scotland car)
Other previous XM sold and broken too many to mention!

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MTXM
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Re: 1992 V6sei auto gearbox repair

Post by MTXM » Sun Mar 03, 2019 2:53 pm

If the valve block is the issue with the earlier car I have been thinking further about which valve might be responsible. After studying the ATSG Saab 9000 gearbox manual the first and reverse lock up valve seems one possible candidate. If the frluv was jammed open there would be no reverse and possibly no first and therefore no forward gears from stationary. The frluv also controls 1-2 shift which as it happens has always been the least smooth. Another obvious candidate might be the pressure regulator valve, which controls system pressure throughout the transmission and if stuck closed would presumably prevent complete operation of the gearbox? As previously discovered the 3-4 and 4-3 traction valves can prevent operation of all forward gears if held shut, but should not effect reverse. I also wondered about the manual valve on the underside of the block on which the gear selector mechanism operates. Regards, Matthew T.
1989 V6 Exclusive (Poland car) - Now living in a local Motor Museum!
1990 V6sei auto (grey auto)
1990 V6sei manual (gold car)
1990 V6.24 Pallas (Germany car)
1990 V6.24v (Scotland car)
Other previous XM sold and broken too many to mention!

xantia_v6
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Re: 1992 V6sei auto gearbox repair

Post by xantia_v6 » Sun Mar 03, 2019 8:00 pm

Dean wrote:
Sun Mar 03, 2019 9:11 am
Hi Matt

Having lost all drive the first thing i would do is a quick pressure test from the main test port on the front of the box.
Would the sprag clutch's one-way element result in total loss of drive or just a loss of efficiency? i would think there would be some metallic material in the oil if this one-way clutch had failed also.

D
Failure of the sprag clutch will cause loss of all drive, but pressures will be normal. I have experienced a failure equivalent to a filed sprag clutch on the e-type (it was actually the stator support shaft sheared), and although the car drove for several miles, as soon as the speed dropped below 20 MPH it lost all drive.
1999 XM Exclusive V6 24V ES9 Manual (LHD) 105,000 km
1997 Xantia Exclusive V6 (RHD) 45,000 miles

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