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Transmission / Speed sensor intermittent issue

(2008 Hummer H3)
in Barstow, CA on April 05, 2011
I have a transmission slippage issue that I believe has lead to a second engine failure (First for excessive oil consumption at around 80,000 Kilometers vehicle mileage) I experienced a random intermittent problem that occurs usually when I go to accelerate from a traffic signal the speedometer drops to zero and my automatic transmission feels like the clutches are slipping. I then nurse the vehicle to the side of the road, turn off the engine and then re-start. The problem usually goes away. Occasionally it happens while decelerating and then re-accelerating in traffic which is extremely dangerous here in Kuwait. The diagnostics test reveled "Speed sensor intermittent". Dealer replaced the speed sensor just prior to the second "Warranty" engine rebuild at 140,000 with engine knocking. Vehicle also has engine oil loss prior to engine problems. No oil on the ground, radiator or exhaust pipes (Gibson dual) I also have a cold air intake system (Volant)
Displaying 3 answers & 2 comments
Popular Answer
on April 05, 2011
I can't see how a transmission slipping can cause engine failure unless it's due to wild overrevving which is doubtful, I think the trans would fail before the engine in that case. I think you need to find a transmission shop for diagnosis if the dealer can't figure it out. I'm concerned about your engine oil loss, you aren't specific about what kind of engine problems you experience so I don't have any comment on that.
on April 05, 2011
The engine noise sounds like it's coming from the upper end and there is an issue with GM inline series engines and "Cam actuator solenoid screens". I found the information while going over the maintenance packet the the tech put together for warranty purposes. I am currently on my 2 year bumper to bumper extended warranty which went into effect after the vehicle hit 100,000 KM. I will request extensive transmission diagnostics. Thanks for the info sir.
on April 05, 2011
you have had 2 engines but how many transmissions?? the speed sensor issue is more than just a sensor. it could be the trans control module or wiring.
i know it is difficult to find someone in your area, but hunt around for a trans expert to track this down.
i dont think the 2 issues are related at all. you have 2 separate issues you are dealing with.

on April 05, 2011
Thanks for the info Sir. I will request more extensive transmission diagnostics.
on April 05, 2011
If I remember correctly the INPUT SPEED speed sensor (near the transmission pump) wiring was rubbing on the transmission internally on the H3 and the transmission had to be removed and the immediate area of the wiring had to be cleaned from metallic burrs and the insulation needed to be repaired to prevent from intermittent short.
This is might be the problem with your SUV also. The dealer should have the TSB and based on the VIN# they should be able to determine if it applies to your vehicle.
I read the TSB few months ago and unfortunately I don't remember the affected model years.
It would be a big help to know the diagnostic trouble codes. Do you happen to have them?

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