A few more transmission questions
01-02-2004, 11:35 AM
#1
Racer
Thread Starter
A few more transmission questions
Can someone clarify a few questions regarding the tranny.
1. On my plastic fill tank for the tranny, there are three level indicators the bottom most seems to have the marks 20c then about 3/4” higher is the min line then about a ¼” is the max line. The Question – Is the 20c mark the cold transmission fluid level I keep reading about? If so, after the fluid warms up it expands to the min level until it is full hot (80c ?) at which point it’s at the max level.
Can someone confirm that this is correct.
2. Before draining the system my fluid level when cold was above the max line and I was wondering about what seemed to be an overflow tube coming off the top of the plastic tank and going somewhere back on the transmission. Would having too much fluid cause an overflow into this tube and where would it go from here? It seems that the entire underside of the transmission is covered with a nice buildup of solidified dirt encrusted fluid - possibly from this overflow.
3. Lastly when I filled the system I only put back in about two gallons of fluid. I read somewhere that the drain of the pan and converter is only 85% effective. The manual states that for a MY 88 the total capacity of fluid should be 2.46 gal for the system. At 85% this equates to 2.09 gal. which is approx. how much I put in. Unfortunately, this has overfilled the system (up to the min mark in item 1 above). I was wondering why I would have overfilled the system by putting back about 2 gal. - I took out a little more than two gallons ( I measured the amount )… P.S. I did follow the procedure for running the car to pump the fluid into the converter etc…
1. On my plastic fill tank for the tranny, there are three level indicators the bottom most seems to have the marks 20c then about 3/4” higher is the min line then about a ¼” is the max line. The Question – Is the 20c mark the cold transmission fluid level I keep reading about? If so, after the fluid warms up it expands to the min level until it is full hot (80c ?) at which point it’s at the max level.
Can someone confirm that this is correct.
2. Before draining the system my fluid level when cold was above the max line and I was wondering about what seemed to be an overflow tube coming off the top of the plastic tank and going somewhere back on the transmission. Would having too much fluid cause an overflow into this tube and where would it go from here? It seems that the entire underside of the transmission is covered with a nice buildup of solidified dirt encrusted fluid - possibly from this overflow.
3. Lastly when I filled the system I only put back in about two gallons of fluid. I read somewhere that the drain of the pan and converter is only 85% effective. The manual states that for a MY 88 the total capacity of fluid should be 2.46 gal for the system. At 85% this equates to 2.09 gal. which is approx. how much I put in. Unfortunately, this has overfilled the system (up to the min mark in item 1 above). I was wondering why I would have overfilled the system by putting back about 2 gal. - I took out a little more than two gallons ( I measured the amount )… P.S. I did follow the procedure for running the car to pump the fluid into the converter etc…
01-02-2004, 12:40 PM
#2
Addict
Rennlist Member
Rennlist Member
– Is the 20c mark the cold transmission fluid level I keep reading about?
>> Yes. Per the workshop manual, it is more accurate to check fluid level when cold than when hot. Though there are many places that are not 20 C so there will be some variation.
- Overfill?
>> There are a lot of passages and areas that do not drain when the pan and torque convirter plug are removed. Refilling should be done according to the marks on the tank.
>> Yes. Per the workshop manual, it is more accurate to check fluid level when cold than when hot. Though there are many places that are not 20 C so there will be some variation.
- Overfill?
>> There are a lot of passages and areas that do not drain when the pan and torque convirter plug are removed. Refilling should be done according to the marks on the tank.
01-02-2004, 09:48 PM
#3
Rennlist Member
Rennlist Site Sponsor
Basic rules - with the car level, transmission at operating temp, engine running at idle, transmission in neutral or park, the fluid level should be between the top two lines. The fluid level should never be below the bottom line regardless of the temp, but all other conditions as above.
01-03-2004, 11:53 AM
#4
Racer
Thread Starter
Wally
When you say the fluid level should never be below the bottom line regardless of temp. Which line are you refering to the MIN line or the 20c line?
When you say the fluid level should never be below the bottom line regardless of temp. Which line are you refering to the MIN line or the 20c line?
01-03-2004, 09:46 PM
#5
Three Wheelin'
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The drain back tube dumps the fluid back into the pan.
The cold 20.C mark is only a cold reference point to be used when doing a refill when the transmission is serviced; filter, converter drain, or overhaul. Once the transmission has reached its operating tempeture of 175F to195 F the remaining fluid is pumped in until the level in the tank is between the 0MAX and 0MIN. Like Wally has said, the level on a hot transmission on level ground engine running in P or N should never be above or below these two marks.
You will notice on some cars an extremely high fluid level in the tank when cold. This usually happens when the car has been sitting over night. The reason for this is when the transmission seals and bushings in the pump and input shaft start to wear, the fluid in the torque converter, starts to drain out past the worn parts into the pan, there by rising the fluid level. This also happens to cars with no worn parts. Once the car is started and the converter charges the fluid level will read normal. The symptoms of this condition would be a big delay into gear until the converter charges with fluid.
The cold 20.C mark is only a cold reference point to be used when doing a refill when the transmission is serviced; filter, converter drain, or overhaul. Once the transmission has reached its operating tempeture of 175F to195 F the remaining fluid is pumped in until the level in the tank is between the 0MAX and 0MIN. Like Wally has said, the level on a hot transmission on level ground engine running in P or N should never be above or below these two marks.
You will notice on some cars an extremely high fluid level in the tank when cold. This usually happens when the car has been sitting over night. The reason for this is when the transmission seals and bushings in the pump and input shaft start to wear, the fluid in the torque converter, starts to drain out past the worn parts into the pan, there by rising the fluid level. This also happens to cars with no worn parts. Once the car is started and the converter charges the fluid level will read normal. The symptoms of this condition would be a big delay into gear until the converter charges with fluid.