Low gear appears to be gone..
94 Brave 27RC with 454 chevy engine apparently has lost the low gear. 110,000 total miles. I can still drive but nervous about moving it unless absolutely necessary. I live in Florida where it is real...
Forum Discussion
I do not recall when GM stopped using engine vacuum to change over from second gear to drive. Back in the 80's, low engine vacuum would cause the transmission to downshift because it thought it was 'under heavy load and wide open throttle'. This would happen when the transmission to engine vacuum line either melted a hole in it (leak) or fell off one end or the other, and it would be stuck in second gear at highway speeds.
Yes dirty fluid can cause a bunch of problems. One way to change the fluid is get a huge flat plastic storage container, and loosen all the transmission bolts, all about 1 turn, then starting at one end, remove one, and loosen all the ones next to it by about 4 turns until one corner of the pan starts to fall, and it will start leaking transmission fluid all over the pan, but mostly in the corner you started in. This is how you get to the transmission fluid filter, that is built into the bottom of the transmission pan.
Another way to 'flush' a system, and also get more of the fluid out of the transmission torque converter is to disconnect one of the transmission fluid cooler lines. Then start the engine and run it until no more fluid comes out. Do not run without any fluid coming out, as there is no lubrication going on while there is no fluid being returned to the transmission. Once the fluid stops coming out of the transmission cooler lines, then removing the transmission pan is trouble free, as it will only have about 1 gallon of fluid still in it, and will not make nearly the mess as removing it while still full of fluid.
When I checked my transmission back in 2006, I found debris on the dipstick (engine off) and cleaned the dipstick, but kept getting dirt, so I knew I had to drain it and replace the internal pan filter right away. So with a 18" X 36" (Christmas wrapping paper storage box) under the RV with me, I loosened all the bolts starting at one end dropped the pan, and drained everything. There was some metal on the magnet that is attached to the bottom of the pan, and I was thinking "Sure, now I need to spend $3,000 on a rebuild - Just after the 6 year warranty expired".
After replacing the pan filter, putting in new fluid, and test running it at home to get it warm, and adjusting the fluid level (it expands so must be tested HOT and set to the lowest possible level when parked with the engine on) to the lowest full mark, I was ready for a trip. I drove it up to Victorville, up the long 6% I15 grade from sea level to 4,500' elevation. Camped for a week, and came home. I checked the fluid again, it looked fine, so I disconnected a fluid line this time, ran the engine, then it was easy to drop the pan, inspect everything (no metal on the magnet this time) and put another case of new fluid into the transmission.
That was at about 31,000 miles on the RV, and now it has around 44,000 miles on it, nothing else has been done to the transmission since that time. Of course I did not drive the RV for the past 6 years.
So yes you should change the transmission fluid and internal filter. It will be open, and perhaps the mechanic can see into the bottom of the transmission, and see if the clutch is all burnt up, or can be tightened a bit? If they are getting out a LOT of debris, then a rebuild might be due now. But with new fluid, filter, and some good luck, you might get several more years out of this transmission.
Good luck,
Fred.
Yes dirty fluid can cause a bunch of problems. One way to change the fluid is get a huge flat plastic storage container, and loosen all the transmission bolts, all about 1 turn, then starting at one end, remove one, and loosen all the ones next to it by about 4 turns until one corner of the pan starts to fall, and it will start leaking transmission fluid all over the pan, but mostly in the corner you started in. This is how you get to the transmission fluid filter, that is built into the bottom of the transmission pan.
Another way to 'flush' a system, and also get more of the fluid out of the transmission torque converter is to disconnect one of the transmission fluid cooler lines. Then start the engine and run it until no more fluid comes out. Do not run without any fluid coming out, as there is no lubrication going on while there is no fluid being returned to the transmission. Once the fluid stops coming out of the transmission cooler lines, then removing the transmission pan is trouble free, as it will only have about 1 gallon of fluid still in it, and will not make nearly the mess as removing it while still full of fluid.
When I checked my transmission back in 2006, I found debris on the dipstick (engine off) and cleaned the dipstick, but kept getting dirt, so I knew I had to drain it and replace the internal pan filter right away. So with a 18" X 36" (Christmas wrapping paper storage box) under the RV with me, I loosened all the bolts starting at one end dropped the pan, and drained everything. There was some metal on the magnet that is attached to the bottom of the pan, and I was thinking "Sure, now I need to spend $3,000 on a rebuild - Just after the 6 year warranty expired".
After replacing the pan filter, putting in new fluid, and test running it at home to get it warm, and adjusting the fluid level (it expands so must be tested HOT and set to the lowest possible level when parked with the engine on) to the lowest full mark, I was ready for a trip. I drove it up to Victorville, up the long 6% I15 grade from sea level to 4,500' elevation. Camped for a week, and came home. I checked the fluid again, it looked fine, so I disconnected a fluid line this time, ran the engine, then it was easy to drop the pan, inspect everything (no metal on the magnet this time) and put another case of new fluid into the transmission.
That was at about 31,000 miles on the RV, and now it has around 44,000 miles on it, nothing else has been done to the transmission since that time. Of course I did not drive the RV for the past 6 years.
So yes you should change the transmission fluid and internal filter. It will be open, and perhaps the mechanic can see into the bottom of the transmission, and see if the clutch is all burnt up, or can be tightened a bit? If they are getting out a LOT of debris, then a rebuild might be due now. But with new fluid, filter, and some good luck, you might get several more years out of this transmission.
Good luck,
Fred.
