Pirate 4x4 banner

1 - 20 of 24 Posts

·
THE ROCK GODS
Joined
·
1,371 Posts
Discussion Starter · #1 ·
I have been batteling an overheating tranny for years, here is what i have:

C4 (3 speed auto) behind a 4.0 v6, reaches 250 degrees every time I go out, has for years, in a light rig
cooling lines are not near exhaust, go through built in radiator cooler, then a large b&m cooler, the pressure of the cooling lines seems good, with no obstructions. I have changed filters and oil often, never see any signs of burnt/discolored oil/burnt smell
sending unit is in the pan (oversized alum pan), I have changed sending units and temp gauge, so thats not the problem.

250 seems too high, but I have never had a tranny problem. I want to hook a fan to the b&m cooler, but cant find a fan that small.

I have relocated coolers, lines several times, with no change
I have reversed the order of flow through the coolers with no change
at one point I ran two external coolers instead of one with no change


so if im not having any tranny problems, what could be the cause?


the tranny was orginally a rebuilt C5, I put a manual valve body in it from a C4, thus making it a C4

I have never had a tranny problem, but at 250*, seems like i should
 

·
Registered
Joined
·
18,277 Posts
have you been running the same guage for that long? I find it hard to believe that your tranny has been at 250º for years and hasn't failed/slipped.


never mind...my reading sucks today
 

·
Registered
Joined
·
4,694 Posts
is it a full manual valvr body?

these have a tendency to cause the trans to run hot because they run full line pressure all the time so the pump is at full pressure at all times. naturally this is going to heat the fluid.

buy the big b&m hi-tek cooler with the fan on it and find a place to mount it under the rear portion of the floor somewhere. Hook it up to a spal controller with a temp sensor in the pan and set it where you want it to run. this cooler, combined with a plate cooler in front of the radiator keeps my C6 happy and never allows it to go over 200*.
 

·
Premium Member
Joined
·
2,163 Posts
You've mentioned its a light rig, but, what tires and gearing is it in the axles?

Undergeared axles heat up automatics pretty good. I believe there was a test years ago in 4 wheeler with a K-blazer on basic 35" MTs. Going from 3.08s to 4.56s dropped their trans temps by 90* or so.

The autos with their slip and low end torque multiplication help make up for high gears, at the cost of heat.
 

·
Premium Member
Joined
·
2,291 Posts
For what it is worth...when I had my bronco with the C-4 and a B&M cooler I always saw temps around 250. My Dad ran the same set-up with higher gears, but with a basic tranny cooler and never had any problems. On the cruiser I do not run it through the radiator with a basic tranny cooler and never see temps near 250 unless it is a long climb on the freeway.
I do not think the B&M cooler flows enough air. Is this the cooler you are running or similiar??
http://store.summitracing.com/partdetail.asp?autofilter=1&part=BMM-70266&N=700+115&autoview=sku
 

·
Vendor
Joined
·
1,609 Posts
find a lazer digital thermometer and check around the trans, pan, cooler, lines, ect. and find a real temp. Maybe its really not getting that hot and your gauges and sending unit sux.

How long does it take to heat up?
what about throwing snow in the cooler to help cool faster? have you ever tried this and noticed a temp change?
where is the cooler located? in the front to get fresh air? electric fan on it?

good luck,
my tranny's have always ran hot, but maybe thats because of the skinny gofast pedal.
 

·
Registered
Joined
·
837 Posts
Where is you sender?
x2!

Is it "t"d into the output line that feeds the cooler? This is going to be very hot. I have mine stuck into the side of the oil pan. My AW4 barely gets above 180*...on the street or on the trail (I have 2 stock trans coolers, and an electric fan).
 

·
Premium Member
Joined
·
2,163 Posts
x2!

Is it "t"d into the output line that feeds the cooler? This is going to be very hot. I have mine stuck into the side of the oil pan. My AW4 barely gets above 180*...on the street or on the trail (I have 2 stock trans coolers, and an electric fan).
YEah, its hot there....but, that is whats coming out of the trans, so thats the internal temp of the fluid, at least in sections of the trans.

Wouldn't you rather know the real temp, rather than put the sender somewhere else, just to feel better about an artificially lower number?
 

·
Registered
Joined
·
4,694 Posts
YEah, its hot there....but, that is whats coming out of the trans, so thats the internal temp of the fluid, at least in sections of the trans.

Wouldn't you rather know the real temp, rather than put the sender somewhere else, just to feel better about an artificially lower number?
putting the sender in the pan tells you how hot the fluid is going into the pump, which IMO is better than knowing how hot the fluid is coming out. Nice cool fluid going in makes for a happy transmission.
 

·
Registered
Joined
·
1,603 Posts
You've mentioned its a light rig, but, what tires and gearing is it in the axles?

Undergeared axles heat up automatics pretty good. I believe there was a test years ago in 4 wheeler with a K-blazer on basic 35" MTs. Going from 3.08s to 4.56s dropped their trans temps by 90* or so.

The autos with their slip and low end torque multiplication help make up for high gears, at the cost of heat.
He's running something like 5.13 gears and 39.50 Iroks. It always runs hot, there was no change from when we were at the hammers a month ago to running the Rubicon two weeks ago in rain and snow.
 

·
THE ROCK GODS
Joined
·
1,371 Posts
Discussion Starter · #16 ·
the sending unit is in the pan, and i have used a B&M gauge/sending unit, and a high quality autometer/sending unit, both with the same readings, I have had the sending unit in line and in the pan with same results.

the B&M cooler is mounted away from the radiator, and yes the temp does go down some if i put snow or water on the cooler

does not seem to overheat at highway speeds

running 40", 5:13s and a 5.0 atlas

Im not sure of the stall (stock ranger/B2)

this was a c5 form a ranger, same as the c4 but with lock up converter, the valve body from a c4 was swapped onto the c5, this was done years ago

What i dont understand, is how can my tranny still be working, its been at 250* for years with no signs of the oil breaking down. I generally stop and let it cool when the needle just goes over 250*

I have the big B&M cooler (w/o fan) mounted near the firewall/passengers feet/floor area. cant seem to find any fans that small, thinking of getting one for a street bike and mounting it there.

my tranny does not slip or have any other problems i am aware of, could there be something wrong with the pump or similar, seems to have good pressure

someone had mentioned that the manual valve body may be causing to much pressure in the pump, how can i solve this?
 

·
Registered
Joined
·
4,977 Posts
A pump is a pump, the manual valve body just uses all/most of the pressure that it puts out and directs it to the clutches and servos appropriatly. They make coolers with fans built in for around $150, there's no need to beat your brains out looking for some fan that is small enough and otherwise fits the bill.
 

·
Registered
Joined
·
1,460 Posts
the sending unit is in the pan, and i have used a B&M gauge/sending unit, and a high quality autometer/sending unit, both with the same readings, I have had the sending unit in line and in the pan with same results.

the B&M cooler is mounted away from the radiator, and yes the temp does go down some if i put snow or water on the cooler

does not seem to overheat at highway speeds

running 40", 5:13s and a 5.0 atlas

Im not sure of the stall (stock ranger/B2)

this was a c5 form a ranger, same as the c4 but with lock up converter, the valve body from a c4 was swapped onto the c5, this was done years ago

What i dont understand, is how can my tranny still be working, its been at 250* for years with no signs of the oil breaking down. I generally stop and let it cool when the needle just goes over 250*

I have the big B&M cooler (w/o fan) mounted near the firewall/passengers feet/floor area. cant seem to find any fans that small, thinking of getting one for a street bike and mounting it there.

my tranny does not slip or have any other problems i am aware of, could there be something wrong with the pump or similar, seems to have good pressure

someone had mentioned that the manual valve body may be causing to much pressure in the pump, how can i solve this?
The manual valve body just keeps a constant high pressure. It doesn't cause too high of a pressure for the transmission. I believe Spal makes fans down to the 9" range. http://etxiow.accpaconline.com/item...t&CFID=1545493&CFTOKEN=97881085&item=30102053
You could even go down to a 4" from them. I would think you would want something up in the 10" range,something that pretty much covers the face of the entire cooler you have.
 

·
Registered
Joined
·
4,465 Posts
I just plumbed in a second tranny cooler. It was easier then replacing or moving the existing derale dual plate with fan.
 

·
Vendor
Joined
·
1,609 Posts
I had mine mounted beneath the floor, with a fan from a streetbike. It didn't seem like it was getting sufficient airflow! when i tubed out the back i stuck it in the side fender blowing straight out and now it works great. dropped my temp by probably 25%
 
1 - 20 of 24 Posts
Top