Dodge Cummins Diesel Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
68 Posts
Discussion Starter #1
I have a built transmission and am running close to half of the power rating. So I haven't been pushing it. It's rated for 850hp and I've only put about 25,000 miles on it.

I recently discovered that the heat exchange was leaking coolant into the transmission and have no idea for how long, I've since bypassed it and am working on installing a larger, secondary cooler under the bed.

When I removed the pan last, there were large amount of friction material in the pan along with both steel and aluminum fragments. For the most part, the transmission runs completely fine. I really don't notice any issues except for two.

From what I can tell, my torque converter is gone. I've noticed that my trans temps increase when I lock the converter and cool when I unlock. So maybe that is where all the friction material came from, idk. Regardless, I will be replacing that since the temps should cool with a locked converter.

Now this other issue I only have every so often and is what I'm unsure of. I have a full manual valve body and every so often when I have my first start up of the day, 1st gear almost doesn't want to move. Even if I idle the truck in neutral for 5 minutes. Almost feels like there is drag or something because even with twice as high RPM as I'd usually apply. the truck is very very slow. I usually just throw it in 2nd and it's completely fine. 2nd and 3rd gear have never had any issues.

Once the truck has driven a mile or so, the 1st gear issue is gone and I won't see it the rest of the time even if I sit for a while and start it up again.

I'm hoping to get by with just a torque converter replacement, but what could this 1st gear issue be?
 

·
Registered
Joined
·
3,973 Posts
Unfortunately atf and coolant mix kills 95% of any automatic trans .
One can flush with fluid and pray ,, but you already have clutch material in the pan , and who knows what in the valve body .
 

·
Registered
Joined
·
79 Posts
Unfortunately atf and coolant mix kills 95% of any automatic trans .
One can flush with fluid and pray ,, but you already have clutch material in the pan , and who knows what in the valve body .
I agree. If you’ve got mixing in there it’s likely lubrication failed.

I assume when the transmission was “built”, they included a valve body that pumps in park? Otherwise it could be TC drain back or a number of other things.
 

·
The 10th Man
Joined
·
4,366 Posts
I'm going to guess you have a valve sticking in the valve body. The fact that it's normal once you put it in 2nd is the red flag here. Obviously could be wrong here, but that's my guess.
 

·
Registered
Joined
·
68 Posts
Discussion Starter #5
I'm going to guess you have a valve sticking in the valve body. The fact that it's normal once you put it in 2nd is the red flag here. Obviously could be wrong here, but that's my guess.
Interesting. I'll disassemble that and go through everything when I install a new converter then to be sure.

Unfortunately atf and coolant mix kills 95% of any automatic trans .
One can flush with fluid and pray ,, but you already have clutch material in the pan , and who knows what in the valve body .
Maybe some of that material got past the filter and dirtied things up.. I suppose I'll find out but this would be an easy fix.

I agree. If you’ve got mixing in there it’s likely lubrication failed.

I assume when the transmission was “built”, they included a valve body that pumps in park? Otherwise it could be TC drain back or a number of other things.
Yes, It SHOULD flow in park as that was the case. I thought maybe converter drain back could be part but I do have a check valve on the transmission line (near where factory was) and if I had it idle in Neutral for 5 minutes and it still had the issue, I would think that would be more than enough time for the fluid to be pumped all back through.
 

·
Registered
Joined
·
84 Posts
If you have metal chunks in the pan that is not a good sign. As said above coolant and ATF do not mix. I would plan on replacing the trans. Somewhere down the road. Not going into first is usually a fluid pressure issue. Valve body could be an issue. But pumps are usually the first thing to go. When the lube goes bad.
 

·
Registered
Joined
·
1,643 Posts
When you get coolat in a transmission it's over. Pull the trans and rebuild it. coolant eats the clutchs and swells the seals. It would not be a good idea to replace the converter it will be ruin again
 

·
Registered
Joined
·
68 Posts
Discussion Starter #9
I finally removed my heat exchanger. I had the transmission inlet and outlet capped since they were AN fittings for the last month or so only coolant was running through it.

When I posted this and when I last took my pan off, I had thought coolant got in because it was seemed to smell like it, it was a very dark red/brown (black without a light) and my transmission has been leaking small amounts of fluid from inside the bellhousing and the coolant seemed to have a red tinge to it.

When I took the heat exchnager out on the bench, I removed one cap and pressured the transmission side with air up to about 90 PSI. and it didn't seem to leak. When I poured the rest of the fluid out of the trans side of the heat exchanger, the remaining fluid still seemed red and fine.

I'm sure the coolant side goes over 90 psi when I bring the engine to about 3k, and maybe any cracks arn't exposed to a lower pressure yet. But now I'm not sure what is going on. and the transmission never got over 200* in the pan since I've installed it.

Obviously my issues still exist and I need a new converter and a cleaning because of the metal particles, but I'm not sure what to think on the supposed fluid contamination.
 
1 - 9 of 9 Posts
Top