Trans overheating
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Trans overheating I posted this in the automatic transmission section but once again, slow response. I know I can always get a quick one here!
I did run a search, read all the threads, but still am kinda stumped on my tranny. It's a 700r4 with 3500 stall, non lockup. Tonight I went to the local cruise in and after about 20 miles of driving or so, my tranny temps start heading upwards of 220 and at 250 by the time I parked. Outside temp was about 90 and my engine temp was about 200 as well. Coming home, temp had dropped to about 70 and trans temp was down to 210 and engine to about 175. I have TWO auxilary transmission coolers, Derale pan, temp sender in the pressure test port. I have no way to verify temp with PCM, obviously. I have the coolers on the front of the radiator, no condenser. Looks to me like they could cool well there. I will double check my fluid level tomorrow. Not sure why I am running so hot. I have noticed my engine oil temp and trans temp seem to run neck and neck. The trans temp sender is a replacement so I double checked the PNs and the same sender is used for both apps. Thought maybe I got a different sender by accident.....
I did run a search, read all the threads, but still am kinda stumped on my tranny. It's a 700r4 with 3500 stall, non lockup. Tonight I went to the local cruise in and after about 20 miles of driving or so, my tranny temps start heading upwards of 220 and at 250 by the time I parked. Outside temp was about 90 and my engine temp was about 200 as well. Coming home, temp had dropped to about 70 and trans temp was down to 210 and engine to about 175. I have TWO auxilary transmission coolers, Derale pan, temp sender in the pressure test port. I have no way to verify temp with PCM, obviously. I have the coolers on the front of the radiator, no condenser. Looks to me like they could cool well there. I will double check my fluid level tomorrow. Not sure why I am running so hot. I have noticed my engine oil temp and trans temp seem to run neck and neck. The trans temp sender is a replacement so I double checked the PNs and the same sender is used for both apps. Thought maybe I got a different sender by accident.....
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Something else I thought of is the order of the cooler lines. I need to double check my routing, but on the trans, top line should be return and bottom should be out right?
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Well no I started thinking since my coolers are mounted vertically, then line order wouldn't matter right? Cooler positioning shouldn't affect cooling ability should it?
Did you try putting it in drive instead of OD? 3500 non-lockup with OD is going to slip a lot unless you are at high speeds then wind resistance will make it slip a lot anyway. The 4.11s should help keep engine rpms up to keep the converter closer to stall but I think it just isn't enough.
MANY of us run 3400+ lockup converters with numerically lower gears and less cooling with no problem.
MANY of us run 3400+ lockup converters with numerically lower gears and less cooling with no problem.
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I was on the highway and is the reason for using OD. And yes the slipping is very evident. At the cruise in, driving around the strip, I was manual shifting and saw little OD but trans was still pretty warm--about 230. Maybe my gauge is out of whack but I tend to think it really is running hot. So you think my converter could be the heating culprit?
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Well I took a line off after the first cooler to see if I was getting flow and plenty of pressure and that dept is covered cuz I made a mess in no time. I didn't realize that non lockup converter would have to work so hard in OD. I guess that's why the TH-350 and 400 guys didn't have any problems. I'll just have to drive around in D. 
I don't know that it's really feasible to sink $2500 in a TH-350 swap right now so you think I can cool this bitch to buy me some time? Am I wasting my time with a cooler with a fan?
I don't know that it's really feasible to sink $2500 in a TH-350 swap right now so you think I can cool this bitch to buy me some time? Am I wasting my time with a cooler with a fan? LS1 Tech Stories
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You can try additional cooling but it with the in radiator plus a fairly small external "thermostatic" plate style and an external filter I find my tranny not up to 160 till I either get on it and warm it or like 20 minutes of normal driving.
The "thermostatic" cooler uses a viscosity bypass circuit not actual tempatures that is why I put it in quotes, they are available from TruCool and B&M.
A converter begining to go bad by the fins bending will cause gross inefficiency and rapid overheating and yes a converter going bad will take out a tranny they shared fluid and when one creates debris it will damage the other.
The TH400/350 guys don't run small diameter 3500 stalls on the street the lack of lockup means they would run quite hot, ask the local carbed guys and they will think 3000+ stalls in a street car is nuts it is the lockup that makes they work so well for us. The OD just compounds the non-lockup problem.
The "thermostatic" cooler uses a viscosity bypass circuit not actual tempatures that is why I put it in quotes, they are available from TruCool and B&M.
A converter begining to go bad by the fins bending will cause gross inefficiency and rapid overheating and yes a converter going bad will take out a tranny they shared fluid and when one creates debris it will damage the other.
The TH400/350 guys don't run small diameter 3500 stalls on the street the lack of lockup means they would run quite hot, ask the local carbed guys and they will think 3000+ stalls in a street car is nuts it is the lockup that makes they work so well for us. The OD just compounds the non-lockup problem.
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Well the only other thing I could do is electric fan cooler but I don't know that it would really cool me down enough to make this thing last. I'd hate to throw some money at it to make it lockup and not mention taking the thing out. If it comes out, TH-350 is going back in. I'll see what I can do with cooling and if it don't work, I guess I'll have to experiment with no OD and short trips to avoid overheating. I really never thought about the OD vs stall issue creating heat but it does make sense. I guess I'll just ride the old horse till she drops dead.
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Originally Posted by LT-x7
Is the 700R4 modified to run a non-lockup converter?
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Originally Posted by Honda Hunter
A fan wont do nothing until you fix the real issue. Did you say it's not locking up? Did I miss something? Why do you have a 700r4?
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From: Monticello, Kentucky
Originally Posted by Honda Hunter
Intresting. Learn something new everyday. well I may be way off but when my converter stopped locking up the temps shot up. Why not get a lock up converter?
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From: Central cali.
Originally Posted by dhdenney
What mods are there for a non lockup converter? I thought if there was no lockup clutch in the converter, and no solenoid in the transmission, you just had a non lockup setup.