Digger87xj
NAXJA Forum User
- Location
- Buffalo Creek/Lakewood CO
You need a new torque converter. Hands down.
-
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Tranny cooler woes
- Thread starter xjtrailrider
- Start date
- Location
- Roanoke VA
Dang! no time for that before the crawl in July. Any temporary fixes?
- Location
- Roanoke VA
I don't think there is anything wrong with the tranny. I have 4 XJ's and a MJ in the driveway right now, all have AW4's and this trail rig on 35's with 4.88's drives just like the rest of them.
I'm a mechanic but not a transmission specialist. I do think I would notice something being wrong with the tranny/torque converter. I'm getting TC lock up right around 35mph(flat land) and it shifts great.
I still think its a air flow issue.
I'm a mechanic but not a transmission specialist. I do think I would notice something being wrong with the tranny/torque converter. I'm getting TC lock up right around 35mph(flat land) and it shifts great.
I still think its a air flow issue.
Digger87xj
NAXJA Forum User
- Location
- Buffalo Creek/Lakewood CO
This statement right here tells all.
The torque converter is causing the heat from too much internal slippage. It doesn't go into lock up in these situations and this is where you say its getting too hot.
QFT.
- Location
- Roanoke VA
On the trail in 1-2 it stays in lock-up all the time with awesome compression breaking(better than my other XJ's). I don't feel any slippage.
Torque Converters can still work when they are going bad....for example, my super duty kept getting really hot but worked fine. It turned out the torque converter was indeed bad, put a new one on and it was perfect.
- Location
- Roanoke VA
Alright. I'm going to try a different cooler set-up on it and if that doesn't work I will put in a new TC.
Digger87xj
NAXJA Forum User
- Location
- Buffalo Creek/Lakewood CO
you are not in lockup until after 35 mph, and only after 2nd gear is achieved. Never will it lock in 1st..
If it were, it would stall the engine, just like a vehicle with a clutch, and you didn't dis engage it.
If it were, it would stall the engine, just like a vehicle with a clutch, and you didn't dis engage it.
- Location
- Roanoke VA
Correct, when in 1-2 and in 4/2-low on the trail it will shift into 2nd before it locks up. It locks up as soon as it goes into 2nd in 4/2-low and will stay there until it shifts back into 1st. It seems to operate the way it should with "as good as" manual shift compression braking.
Let's organize the troubleshooting:
You report the transmission temperature gauge reports the transmission is running hot.
Possible causes:
1. The temperature gauge is faulty and reading high
2. The cooling system is not working.
3. The transmission is putting out excessive heat
Case 1:
Have you ever checked the temperature with another thermometer? You can use an oven thermometer or IR pyrometer for a quick check.
Case 2:
The cooling system will not work properly if either the airflow or the ATF flow is reduced.
Have you checked the actual airflow through the ATF cooler? Mine wasn't blocked by mud -- it was blocked by bees! The car had been driven through a swarm of bees and they completely blocked up the airflow.
Have you checked the rate of flow of the ATF through the system? I found a kink in one of the hard lines near the front of the engine on one car, in a spot I can't imagine how it got kinked. But kinked it was and the flow was only a small fraction of what it should have been.
The most convincing place to check for flow rate is the return line right at the transmission, because that will reveal any blockage anywhere in the ATF cooling system.
Case 3:
I don't know how to measure the heat output of the transmission/torque converter -- some one else will have to chime in on this subject.
You report the transmission temperature gauge reports the transmission is running hot.
Possible causes:
1. The temperature gauge is faulty and reading high
2. The cooling system is not working.
3. The transmission is putting out excessive heat
Case 1:
Have you ever checked the temperature with another thermometer? You can use an oven thermometer or IR pyrometer for a quick check.
Case 2:
The cooling system will not work properly if either the airflow or the ATF flow is reduced.
Have you checked the actual airflow through the ATF cooler? Mine wasn't blocked by mud -- it was blocked by bees! The car had been driven through a swarm of bees and they completely blocked up the airflow.
Have you checked the rate of flow of the ATF through the system? I found a kink in one of the hard lines near the front of the engine on one car, in a spot I can't imagine how it got kinked. But kinked it was and the flow was only a small fraction of what it should have been.
The most convincing place to check for flow rate is the return line right at the transmission, because that will reveal any blockage anywhere in the ATF cooling system.
Case 3:
I don't know how to measure the heat output of the transmission/torque converter -- some one else will have to chime in on this subject.
- Location
- Roanoke VA
No I haven't. I do have one sender that is leaking and I might have the input sender in a bad place and its picking up heat from the engine. I ordered 2 new senders and will relocate them when I install the new cooler.
I found my ZJ fan clutch to be bad today, ordered a new one. It was still loose when the engine was hot.
Going to check this when I flush the tranny.
I have no idea how to measure this either other than my B&M gauge and senders.
My tranny shifts and operates as it should. If I felt like the tranny was bad it would already be out and the low mileage 96 AW4(90k) that I have sitting in the garage would be in there already!
Fix the fan clutch and after the flush, if it is still an issue, swap the torque converter out with the one you have in the garage (if it has one) before swapping transmissions.
- Location
- Roanoke VA
Will do. I picked up 3 gallons of cheap merc/dex3 today for the flush and a new filter. I think I have a couple of extra torque converters.
XJLI
NAXJA Forum User
- Location
- Long Island, NY
my jeep has 105k on the clock, the drivetrain is original. my trans shifts smooth and solid, never slips, and downshifts quickly when it needs to. according to my gauge, its getting up to 180-200F in stop and go traffic... as soon as i get going and the TC locks up, the temp drops real quick. on the highway the needle doesnt even move much over 100F.
according to this thread, my torque convertor is bad? tranny has pretty all new fluid in it (drain and refill 3 times) and a new filter. its a b&m gauge (from the kit everyone has) with a 12x6ish cooler.
according to this thread, my torque convertor is bad? tranny has pretty all new fluid in it (drain and refill 3 times) and a new filter. its a b&m gauge (from the kit everyone has) with a 12x6ish cooler.
Digger87xj
NAXJA Forum User
- Location
- Buffalo Creek/Lakewood CO
No, those temps are perfect.
OP's temps are hitting 260* and coming back to the trans after cooler at 220*. That is trans destroying. Breaks down the fluid, hardens seals, etc.
OP's temps are hitting 260* and coming back to the trans after cooler at 220*. That is trans destroying. Breaks down the fluid, hardens seals, etc.
XJLI
NAXJA Forum User
- Location
- Long Island, NY
well then. good.
- Location
- Roanoke VA
Found another issue with my tranny cooler. I somehow, between the cooler lines at the oil pan and the cooler in the grill, got the lines swapped. So I was putting fluid in the top and out the bottom. This is opposite of what I was going after and most likely was part of my cooling issues. Gonna fix that issue with the new cooler.
- Location
- Roanoke VA
Finally got the new cooler installed today, flushed the tranny with 3 gallons of fresh dex/merc. I still need to change the filter and test drive it.
Why is my tranny reading 200* just sitting in the garage at idle in 80* weather? I have two new B&M senders on the input/output of the cooler so I know they are good.
The fluid that came out was brown but no burnt smell. I had a strong stream out of the tranny so I'm sure the pump is good.
Why is my tranny reading 200* just sitting in the garage at idle in 80* weather? I have two new B&M senders on the input/output of the cooler so I know they are good.
The fluid that came out was brown but no burnt smell. I had a strong stream out of the tranny so I'm sure the pump is good.
- Location
- Roanoke VA
Okay, I'm a a loss 
The tranny is flushed, new filter, new Derale 26" cooler and 2 new B&M sending units(one before the cooler and one after).
I start it up, go around the block and the temp gauge is reading hot already(the gauge climbed in large jumping increments). Its reading 260* sitting at idle in the driveway WTH!
So I get out my small probe style temp gauge and test it on the radiator and I get exactly what my engine temp gauge is saying so I know the probe gauge is working. I stuck the probe in between both tranny lines and I get 140*. I can hold my hand on the lines, not for long, but for about 15 seconds before it gets uncomfortable.
I'm beginning to think my B&M gauge has gone south on me. I can't see this tranny running this hot after a five minute test drive in 70* weather even if the TC was trashed. It shifts fine and crisp.
Gauge? Or is it still the TC?
The tranny is flushed, new filter, new Derale 26" cooler and 2 new B&M sending units(one before the cooler and one after).
I start it up, go around the block and the temp gauge is reading hot already(the gauge climbed in large jumping increments). Its reading 260* sitting at idle in the driveway WTH!
So I get out my small probe style temp gauge and test it on the radiator and I get exactly what my engine temp gauge is saying so I know the probe gauge is working. I stuck the probe in between both tranny lines and I get 140*. I can hold my hand on the lines, not for long, but for about 15 seconds before it gets uncomfortable.
I'm beginning to think my B&M gauge has gone south on me. I can't see this tranny running this hot after a five minute test drive in 70* weather even if the TC was trashed. It shifts fine and crisp.
Gauge? Or is it still the TC?
Prom3theus
NAXJA Forum User
- Location
- Cleveland
After reading the thread, my own 2 cents: I believe your sensor could be messed up, but I am a little confused though, you mentioned 2 B&M gauges, one for pressure, one for return, are they both indicating 260-ish (one 260 one 220)? It could be a bad wiring/ground if that happens. Also, the fact that they jump in big increments to 260 makes my suspicion even stronger.
Other than that, I have used so far 2 Tru Cool transmission coolers, with great results:
Big (40k CVW) LPD47391 (installed on a Liberty CRD)
Smaller (30K GVW) LPD49211 (installed on the Cherokee).
On the Cherokee, I had never seen more than 170 no matter what I do (I also have the same B&M gauge but I read the pressure line), no matter how many hours I am in city stop and go traffic or on one of my few times a year offroad. If you are thinking to upgrade, this is a great alternative.
And thanks for that Derale link, I didn't know thy make something like that, very cool idea!
Other than that, I have used so far 2 Tru Cool transmission coolers, with great results:
Big (40k CVW) LPD47391 (installed on a Liberty CRD)
Smaller (30K GVW) LPD49211 (installed on the Cherokee).
On the Cherokee, I had never seen more than 170 no matter what I do (I also have the same B&M gauge but I read the pressure line), no matter how many hours I am in city stop and go traffic or on one of my few times a year offroad. If you are thinking to upgrade, this is a great alternative.
And thanks for that Derale link, I didn't know thy make something like that, very cool idea!