transmittion not shifting into overdrive
10-14-2009, 11:51 PM
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transmittion not shifting into overdrive
Hi our 91 Bonny does not shift into overdrive or lockup. The engine seems to be running cold. No heat from heater. I thought I read that the engine needs to be a certain temp before it will shift to overdrive. What kind of tests can I do to tell ehat is wrong. thanks duncan
10-15-2009, 12:07 AM
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First thing you want to do is check the fluid, is it clean and at the right level? How old is the filter? Here'* a trouble shooting guide for you to look at. https://www.gmforum.com/t279700/
10-15-2009, 08:12 PM
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Thanks for the replys. We bought the car in a salvage yard. It had sat for two years without being ran.So don't know how the trans filter is.What do I need to do to find the problem Thanks again. This is our 3rd Bonne No 1 525000 km no 2 369000 km rusted to much under front frame.no 3 255000km.
duncan
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10-15-2009, 08:20 PM
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There is a product called MT-10, which is a metal treatment, that we use to free stuck valves in transmissions, especially after they have been sitting a long time.
10-15-2009, 09:03 PM
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I checked the trans oil and it looks nice and red and smells like trans oil as near as I can tell.It could be linckage adjustment too. duncan Thanks for the replys.
10-16-2009, 03:08 AM
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I also experienced my transmission did not go to 4th gear after I replaced the 190 deg T-stat. I had a mechanic took a look at it and said the trans must come out. When he took it out and took the trans apart (60%) when I got there to have a loook at my trans I had 5 damaged parts related to 4th gear the 4th gear clutch ***'y. I had the entire trans replaced at the fraction cost of rebuilding the trans
My car is a 1990 Bonneville SSE with a 4T60 (440T4) Trans.
My car is a 1990 Bonneville SSE with a 4T60 (440T4) Trans.
10-18-2009, 05:45 PM
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Hi all Today I replaced the T Stat 195 degree that worked good but I don't know if it helped the shifting as when I put the floor shift in first it still shifts up to third .when I am in od what is the engine rpm supposed to be approx. ours runs around 2500 at 60 miles ph. The car runs strong and fast.
duncan
duncan