Optimal Trans Temps?
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TECH Enthusiast
Joined: Sep 2004
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From: Midland, TX
Optimal Trans Temps? I know this has been covered before but search is down and I need to know ASAP. I just put a TCI 4k stall and cooler in my car and my trans temp gauge should be in later this week. I was wanting to know at what temperature does average transmission fluid break down. Also, which would give a higher temp reading, the service port or the pan? I just had to get my A4 rebuilt a couple of months ago, because if high temps I think, and I just need to know if I need to get a second small cooler or not. Average winter temps so far are 60* and summer is 90*. This car is also a DD. Thanks in advance.
You're not really worried about the average temp.
You're worried about the peak, like you see deep in
a clutch pack while it's slipping under power and
trying to stop. The cooler the fluid the more room
you have, to rise before it varnishes up. "As low as
possible", as long as you stay up above 70F or so
(this being about where TCC lock seems to enable).
The bigger the stall, the more heat, go as big as you
can find with that one. Where you are at, I wouldn't
worry about overcooling.
You're worried about the peak, like you see deep in
a clutch pack while it's slipping under power and
trying to stop. The cooler the fluid the more room
you have, to rise before it varnishes up. "As low as
possible", as long as you stay up above 70F or so
(this being about where TCC lock seems to enable).
The bigger the stall, the more heat, go as big as you
can find with that one. Where you are at, I wouldn't
worry about overcooling.
Thread Starter
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From: Midland, TX
It was about 40* last night and I took a friend for a ride and got on it quite a bit. After a few blocks, it overheated again. I have the 24k cooler mounted in the typical spot in front of the AC condenser but I think I'm gonna have to get a second cooler now. Everytime it overheats, I get stuck in second gear until it cools down. Maybe after I get my trans temp gauge, I won't let it overheat.
BTW, the Bilsteins are still working great. Thanks!
BTW, the Bilsteins are still working great. Thanks!
Thread Starter
TECH Enthusiast
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From: Midland, TX
Where should I mount the temp sensor to get a higher reading, the pan or the service port? Also, what transmission fluid would work best for keeping the tranny cool (heat dispersement) and break down at higher temps than average ATF? I just don't want something to break down just over what my tranny runs after a quick race. I want to have a larger margin between the two.
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From: Edgewood, MD
How are you running the lines for the tranny cooler? I was using an aftermarket one and the stock one and getting too high of trans temps during the summer to be safe. I took the stock trans cooler (it's inside the radiator) out of the loop and am just using the aftermarket one. I've had no problems with trans temps since.
Since you have your trans cooler mounted in the front, another thing which will help slightly (only 2-4 degrees it seems) is to get a cooler thermostat for the car and then program the fans to come on sooner. (Or just programming the fans to come on sooner would be ok too I guess.) The fans are going to help pull a little more air across the trans cooler, especially when you're not moving. Like I said, it doesn't help much...only a few degrees, but it helps.
Another thing which will help when you're driving around town (and not going WOT) is a good tune. 3rd gear lockup will be your friend if you do a lot of non-WOT around town or traffic driving. The trans temps stay cooler with the 'verter locked.
If it was only 40* out and you were overheating, something seems off...I've got a TCS 4200 and I don't see tranny temps above 160* in the winter even with a lot of driving with the 'verter unlocked. (BTW 160* is still in the safe zone as far as tranny temp.) How do you know the tranny was overheating? Do you have some scanner program you're monitoring tranny temps with while driving? Or are you guessing it is overheating because you were locked in 2nd gear?
Since you have your trans cooler mounted in the front, another thing which will help slightly (only 2-4 degrees it seems) is to get a cooler thermostat for the car and then program the fans to come on sooner. (Or just programming the fans to come on sooner would be ok too I guess.) The fans are going to help pull a little more air across the trans cooler, especially when you're not moving. Like I said, it doesn't help much...only a few degrees, but it helps.
Another thing which will help when you're driving around town (and not going WOT) is a good tune. 3rd gear lockup will be your friend if you do a lot of non-WOT around town or traffic driving. The trans temps stay cooler with the 'verter locked.
If it was only 40* out and you were overheating, something seems off...I've got a TCS 4200 and I don't see tranny temps above 160* in the winter even with a lot of driving with the 'verter unlocked. (BTW 160* is still in the safe zone as far as tranny temp.) How do you know the tranny was overheating? Do you have some scanner program you're monitoring tranny temps with while driving? Or are you guessing it is overheating because you were locked in 2nd gear?
Thread Starter
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From: Midland, TX
First off, I have a 160* thermostat with fans tuned to that temp. and the TC is tuned also. I'm not sure of the flow direction so I don't know the order but the factory cooler is still in use with the aftermarket added. The only time I seem to have the problem is when I stall it then take off leaving black marks as far as I can. Driving it hard unlocked hasn't done anything that I know of. I think locking is second is the cause of overheating because the night I got my TC in, I took it for a drive and apparently didn't have my TC completely full of fluid. I stalled my 4k to 5k and the tires still didn't want to break! Stalling it that high filled the TC but my tranny fluid became low. I couldn't get it out of second gear until the next morning after it spent the night cooling off. I just want to know what is optimal temp range for when I get my gauge put on.
Locked but slipping is the worst for heat generation.
Stock trans force motor tables appear to not do
enough to fight decreased pressure (viscosity)
w/ temp, reducing holding power and reinforcing
slip problems in my experience. Not to mention,
my TCI converter was totally incapable of locking
under full power to begin with.
I would want the ATF temp (wherever you sense it,
I just use the in-car one and the scan tool to watch)
under 200F in any case and much prefer it to stay
down at engine coolant temp. I run the cooler before
the radiator so it has a higher delta-T to dump excess,
and let the rad have any that's left. Most folks go the
other way, at least in summertime. But I'm happy with
it and the ATF temp usually stays right at coolant
temp (175 or so).
Anyway I think you and your converter will be a lot
happier if you give up expecting to lock at WOT,
unless you have one designed for the abuse. I
do not think (you could check w/ tech support)
that TCI builds that converter to be capable of
anything more than cruise locking.
Stock trans force motor tables appear to not do
enough to fight decreased pressure (viscosity)
w/ temp, reducing holding power and reinforcing
slip problems in my experience. Not to mention,
my TCI converter was totally incapable of locking
under full power to begin with.
I would want the ATF temp (wherever you sense it,
I just use the in-car one and the scan tool to watch)
under 200F in any case and much prefer it to stay
down at engine coolant temp. I run the cooler before
the radiator so it has a higher delta-T to dump excess,
and let the rad have any that's left. Most folks go the
other way, at least in summertime. But I'm happy with
it and the ATF temp usually stays right at coolant
temp (175 or so).
Anyway I think you and your converter will be a lot
happier if you give up expecting to lock at WOT,
unless you have one designed for the abuse. I
do not think (you could check w/ tech support)
that TCI builds that converter to be capable of
anything more than cruise locking.
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Thread Starter
TECH Enthusiast
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From: Midland, TX
Cruise locking is all mine does. The only thing I'm seeing is that after I stop the car and stall it to 3.5k then run the car about 1/4 mi. or so, it won't come out of second gear, even if I come to a complete stop. I am aware that my TC only locks at cruise above 45 mph but its after I do a run that I can be cruising 60+ and the tach is reading 4k (won't lock up). Like I said, there's not much I know about whats going on in there just yet. I should be getting my temp gauge in a day or two and have it on ASAP.
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On The Tree
Joined: Mar 2003
Posts: 137
Likes: 1
From: Texas
Good solid advice from the two posters above!
Having said that, I'm no tranny guru, but after rebuilding my 4l60e four times now, and learning all the expensive lessons about what NOT to do anymore, my advice, while being in total agreement with the two above, is:
1. According to every trans shop I have talked to, transmission fluids begin to degrade starting at 190' and the higher the temp, the more degradation. The life blood of your tranny IS your fluid and it's condition is critical.
2. Always use a lock-up style convertor, for the reasons stated in the above posts.
3. Every tranny shop, including FLP, that I have had an interaction with has warned to NOT use anything but the GM recommended fluid. Even REDLINE synthetics does not recommend using their product in your GM transmission.
4. Staying in 2nd gear is a recipe for disaster, as there is NO lock-up in 2nd gear, even at cruising speeds, and will burn up your tranny, with a quickness.
5. When it comes to transmission coolers, bigger is always better!
After having my trans rebuilt again the last time, I was told by the trans shop that the transmission cooler installed by my old tuner, was too small and insufficient for my needs, and should not have been hooked up with the radiator. They installed a much larger cooler, took it away from the radiator connection, and let it run on it's on, and I swear, in the four transmission rebuilds I have done, I have NEVER seen the trans temps this low. This is a great, and from what I've seen HONEST, transmission shop, that does great work. They did my last two rebuilds, but the last burn up was my on fault and was well after their 1 year warranty expired.
Having said that, I'm no tranny guru, but after rebuilding my 4l60e four times now, and learning all the expensive lessons about what NOT to do anymore, my advice, while being in total agreement with the two above, is:
1. According to every trans shop I have talked to, transmission fluids begin to degrade starting at 190' and the higher the temp, the more degradation. The life blood of your tranny IS your fluid and it's condition is critical.
2. Always use a lock-up style convertor, for the reasons stated in the above posts.
3. Every tranny shop, including FLP, that I have had an interaction with has warned to NOT use anything but the GM recommended fluid. Even REDLINE synthetics does not recommend using their product in your GM transmission.
4. Staying in 2nd gear is a recipe for disaster, as there is NO lock-up in 2nd gear, even at cruising speeds, and will burn up your tranny, with a quickness.
5. When it comes to transmission coolers, bigger is always better!
After having my trans rebuilt again the last time, I was told by the trans shop that the transmission cooler installed by my old tuner, was too small and insufficient for my needs, and should not have been hooked up with the radiator. They installed a much larger cooler, took it away from the radiator connection, and let it run on it's on, and I swear, in the four transmission rebuilds I have done, I have NEVER seen the trans temps this low. This is a great, and from what I've seen HONEST, transmission shop, that does great work. They did my last two rebuilds, but the last burn up was my on fault and was well after their 1 year warranty expired.
What cooler did you go with? I got the biggest
plain ole Hayden that Pep Boys had on the shelf.
It's been OK given that I don't do sustained high
slip, high output driving much. The only time I had
bad thermal problems was once when I had to run
the A/C and drive up grade for miles, then the
scheme of running through the rad after the cooler
showed its limitations; the condenser heat dump
made the rad unable to hold set temp and the trans
followed. Anyway, what's the model you're happy
with?
plain ole Hayden that Pep Boys had on the shelf.
It's been OK given that I don't do sustained high
slip, high output driving much. The only time I had
bad thermal problems was once when I had to run
the A/C and drive up grade for miles, then the
scheme of running through the rad after the cooler
showed its limitations; the condenser heat dump
made the rad unable to hold set temp and the trans
followed. Anyway, what's the model you're happy
with?
TECH Regular
Joined: Oct 2002
Posts: 465
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From: Edgewood, MD
I'm curious what brand he's got as well. I've got the largest Hayden there is...19,000 I think??
Another thing is...change your trans fluid regularly. (A pan with a drain plug is your friend for that...) I change my fluid every couple of oil changes depending on what I've been doing with the car and what time of year it is. It also gives me a good chance to check the bottom of the pan on a fairly regular basis for any signs of wear or other problems.
Another thing is...change your trans fluid regularly. (A pan with a drain plug is your friend for that...) I change my fluid every couple of oil changes depending on what I've been doing with the car and what time of year it is. It also gives me a good chance to check the bottom of the pan on a fairly regular basis for any signs of wear or other problems.
On The Tree
Joined: Mar 2003
Posts: 137
Likes: 1
From: Texas
Well, I pulled out my invoice, and all it says is external transmission cooler $75.00, but I can call them at some point this week and find out what brand it is.
When I was settling up on the bill in their office, he pointed to the one he put in, which was displayed on his wall. I asked him to give me the one they took out, which he did, and the new one was at least one, if not two times larger than my old one. He showed me how the lines were much larger and would allow for *garbage* to pass through them, whereas the old one had smaller lines and 45' bends @ the connections, instead of mandrel or smooth bends. He told me by not hooking it up to the radiator, my tranny temps would no longer follow that of the coolant, which is a good thing, especially with an underdrive pulley. I hated it when every time I would check my trans temps, they would always just reflect the coolant temp within a few degrees...now it's free from the radiator and constantly low temps, even after grueling runs!
He said, the only way I could improve on his cooler install, would be to get fan assist, wired directly for the cooler unit...but I don't think I'll ever need it, from what I've seen.
Anyway, I'll try to remember to call them and get the brand. I think it was B&M, but not sure.
When I was settling up on the bill in their office, he pointed to the one he put in, which was displayed on his wall. I asked him to give me the one they took out, which he did, and the new one was at least one, if not two times larger than my old one. He showed me how the lines were much larger and would allow for *garbage* to pass through them, whereas the old one had smaller lines and 45' bends @ the connections, instead of mandrel or smooth bends. He told me by not hooking it up to the radiator, my tranny temps would no longer follow that of the coolant, which is a good thing, especially with an underdrive pulley. I hated it when every time I would check my trans temps, they would always just reflect the coolant temp within a few degrees...now it's free from the radiator and constantly low temps, even after grueling runs!
He said, the only way I could improve on his cooler install, would be to get fan assist, wired directly for the cooler unit...but I don't think I'll ever need it, from what I've seen.
Anyway, I'll try to remember to call them and get the brand. I think it was B&M, but not sure.
Thread Starter
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From: Midland, TX
http://texas-speed.com/shop/item.asp...d=392&catid=58
This is what I'm using. Still no temp gauge. Hopefully it will be in tonight. I'd like to know what the tranny is actually reading.
This is what I'm using. Still no temp gauge. Hopefully it will be in tonight. I'd like to know what the tranny is actually reading.
Thread Starter
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From: Midland, TX
I think I may just deal with the one I have until I can get this one: http://cgi.ebay.com/ebaymotors/ws/eB..._BIN_Stores_IT
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From: Midland, TX
Originally Posted by LS69TA
That's the one I want to get. I'm waiting on my trans. temp. gauge to arrive so I can see what mine is running right now for a baseline.
i have a B&M 29,200 cooler and it works GREAT. You don't need a little fan cooler unless your dead set on mounting it somewhere besides infront of the radiator. I have a NON lock up 5,100 stall and it avg 150- 200 depending on the weather (Texas summers). at the track it almost never reaches 200.
Thread Starter
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From: Midland, TX
Finally got my trans temp gauge in today. I'm gonna try to put it on this weekend and see whats going on. I'll keep you guys posted in case there's anyone else thats having the same problem as me.
Ok, so how high is safe to get to? What temp do i not want to pass? Also my car came with a little switch under the steering wheel area, if i turn it on, its another fan. Is this a 160 powerstat or an extra cooler or what? Thanks! No stall yet, getting ready to order and need to know how hot NOT to get
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