I just ordered a new transmission cooler and would have just put it back together but then I just saw your video, went out and removed my lower transmission hose and sure enough a bunch of crap blocking inside the radiator! Thanks for posting this you saved me alot of time trying to figure out this issue!
Thank you very much! I was stuck on the side of the road with an over-heated transmission about 260-270! Motor temp was just fine transmission fluid level was normal.watch your video said what else do I have and hold the bottom transmission line off the radiator and air was a whole bunch of Gunk walking the tube cleaned it out best I can on the side of the road and got on the rest of the way with no problems! Never would have thought of that thank you very much again!
My man. I have been trying to figure these problems out for just under a year did the same thing couldn't find any forums couldn't find any information anybody else had the same problem you my friend are a savior thank you for posting this video you saved me thousands of dollars and hours of time trying to diagnose
Had an issue with my transmission after a 150 mile trip. After stopping to get mail the tranmission seemed to be catching between 1st and 2nd. Will check my trans cooling lines to see if it also has problem. Thanks for putting this up.
My LBZ trans was running cool and all of a sudden the trans went up to 250 and slowly went up to 275 and the trans warning came on and went into limp mode. Finally got it home after it cooled back down while being parked on the side of the road. Still haven't figured out the issue yet but I haven't had time to look at. Going to see if the trans shop can do a full flush, new fluids and filters and see if that'll fix it. Edit: So I drained all of the old fluid, installed new filters, filled with new fluid and it still didn't fix it. I disconnected all of the lines and ran compressed air through them and no clogs. But the same thing was wrong with my radiator. Bottom hole looked clogged so I ran compressed air through it from the top hole and bits of old trans pan gasket came out. It still overheats but it takes much longer for it to happen. A new radiator is really expensive so I'm going to see if there's a way to super clean and flush it out. The front smaller cooler was perfectly clean.
I know this is 3 years old but, what you are saying happened exactly to me. Driving on the freeway temps started to rise, and didn't notice until the dash said transmission hot idle engine. The trans temp was 300F. Called a few places the specialize in Allisions and told me the Torque converter failed to lock up on the freeway causing excessive slipping resulting in 300F.
I have a 2004 GMC 2500 HD with an allison transmission behind the L18 gasoline big block engine. I can drive my truck 2 miles and shut it for a few minutes and when I restart it I get a message that the transmission is hot and to idle engine. Transmission will not shift. After I idle about 10 minutes the temperature drops to normal temp and Trans will shift perfectly. I'm gonna try your solution and see what it does, but I'm afraid temp sensor unit under valve body inside the transmission may be bad. Good video. I learned something new today.
Well I am visiting this now because today I was pulling over on the side of the highway due to a transmission hot warning sign on my dash. Engine temp find. Transmission in great condition. I am going to troubleshoot it soon. Hopefully this is the issue.
Why do transmission lines go into the radiator? It’s got it’s own little transmission radiator for cooling, how is it not mixing with engine coolant? Stupid question for you guys that know lol but I’ve got no idea. My trans coolant gauge stopped working and I’m looking for answers. Thanks man.
Tyler Burkhard I have Allison 2200hs .my transmission is getting hot above 225 f. Mechanic said metal particles in oil . Inner cooler flow is ok. Gear Shifting is good. Mechanic saying need to change whole transmission . My question is Is metal particles in oil are not normal? What else make this transmission hot or heat up? Thanks and waiting for reply
Could this material have come from the first transmission? Maybe caught in the tubing etc and is now clogging the radiator's trans cooler. Most of these trucks have a cooler in the radiator and an additional cooler in front of the radiator. These transmissions are expensive so I would: clean the radiator, blow out the transmission lines, change the external filter, drop the pan and look for more clutch material if not replace the internal filter and see what happens. This will be lost money and effort if your current transmission is going bad. It still might be worth trying. If the clutch material is going bad from the current transmission could someone have rebuilt it with poor quality material?
Hi robert, Very informative video I have Allison 2200hs .my transmission is getting hot above 225 f. Mechanic said metal particles in oil . Inner cooler flow is ok. Gear Shifting is good. Mechanic saying need to change whole transmission . My question is Is metal particles in oil are not normal? What else make this transmission hot or heat up? Thanks and waiting for reply
Thats is an engine cooler? Mr tranny cooler is mounted in the front in front of the ac condenser. Those lines you showed are engine oil lines. My truck is an 03 duramax. With the allison
No this is your main and first trans cooler the one up front your seeing is our aux transmission cooler hense all duramax and 8.1 with the ally’s have these two (2) coolers
I just ordered a new transmission cooler and would have just put it back together but then I just saw your video, went out and removed my lower transmission hose and sure enough a bunch of crap blocking inside the radiator! Thanks for posting this you saved me alot of time trying to figure out this issue!
Thank you sir. Running at 230F before changing out radiator. Now max temp 185F. Once again thank you for posting this up and trouble shooting.
This video really helped me out. I have the same truck with the same problem.
Thank you very much! I was stuck on the side of the road with an over-heated transmission about 260-270! Motor temp was just fine transmission fluid level was normal.watch your video said what else do I have and hold the bottom transmission line off the radiator and air was a whole bunch of Gunk walking the tube cleaned it out best I can on the side of the road and got on the rest of the way with no problems! Never would have thought of that thank you very much again!
this video saved me from buying a new trans cooler. thank you so much
I didn't look thank you for posting this video. I have bypassed both cooler and did not fix the issue but now I see I could possibly be the line.
My man. I have been trying to figure these problems out for just under a year did the same thing couldn't find any forums couldn't find any information anybody else had the same problem you my friend are a savior thank you for posting this video you saved me thousands of dollars and hours of time trying to diagnose
DITTO!!!!!
I have a 2001 Duramax with Allison transmission, this was the first thing I checked after watching this and this was the issue :-)
Had an issue with my transmission after a 150 mile trip. After stopping to get mail the tranmission seemed to be catching between 1st and 2nd. Will check my trans cooling lines to see if it also has problem. Thanks for putting this up.
Thanks for the info bro now I know what to focus on 👍
Thanks for the vid - my turck had the same issue with the same filter element crap clogging it. First thing i checked thanks to this video.
My LBZ trans was running cool and all of a sudden the trans went up to 250 and slowly went up to 275 and the trans warning came on and went into limp mode. Finally got it home after it cooled back down while being parked on the side of the road. Still haven't figured out the issue yet but I haven't had time to look at. Going to see if the trans shop can do a full flush, new fluids and filters and see if that'll fix it.
Edit: So I drained all of the old fluid, installed new filters, filled with new fluid and it still didn't fix it. I disconnected all of the lines and ran compressed air through them and no clogs. But the same thing was wrong with my radiator. Bottom hole looked clogged so I ran compressed air through it from the top hole and bits of old trans pan gasket came out. It still overheats but it takes much longer for it to happen. A new radiator is really expensive so I'm going to see if there's a way to super clean and flush it out. The front smaller cooler was perfectly clean.
I know this is 3 years old but, what you are saying happened exactly to me. Driving on the freeway temps started to rise, and didn't notice until the dash said transmission hot idle engine. The trans temp was 300F. Called a few places the specialize in Allisions and told me the Torque converter failed to lock up on the freeway causing excessive slipping resulting in 300F.
Good to know thanks Amigo a lot
Thanks I’m gonna try this my self
Thank you for this vid mine is running hot bet it’s the radiator
thank you
I have a 2004 GMC 2500 HD with an allison transmission behind the L18 gasoline big block engine. I can drive my truck 2 miles and shut it for a few minutes and when I restart it I get a message that the transmission is hot and to idle engine. Transmission will not shift. After I idle about 10 minutes the temperature drops to normal temp and Trans will shift perfectly. I'm gonna try your solution and see what it does, but I'm afraid temp sensor unit under valve body inside the transmission may be bad. Good video. I learned something new today.
what were the temps you were getting before changing radiators?
Good job
That looks like filter fibers not clutch material.
Well I am visiting this now because today I was pulling over on the side of the highway due to a transmission hot warning sign on my dash. Engine temp find. Transmission in great condition. I am going to troubleshoot it soon. Hopefully this is the issue.
When your transmission got hot did it leak from the bell housing
Was yours still shifting fine when it was running hot
Did it throw a code before u fixed it
4l80e?
Why do transmission lines go into the radiator? It’s got it’s own little transmission radiator for cooling, how is it not mixing with engine coolant? Stupid question for you guys that know lol but I’ve got no idea. My trans coolant gauge stopped working and I’m looking for answers. Thanks man.
That’s all clutch material in the cooler meaning your clutch’s and/or torque converter are shot.
Tyler Burkhard
I have Allison 2200hs .my transmission is getting hot above 225 f. Mechanic said metal particles in oil . Inner cooler flow is ok. Gear Shifting is good. Mechanic saying need to change whole transmission .
My question is
Is metal particles in oil are not normal? What else make this transmission hot or heat up?
Thanks and waiting for reply
Could this material have come from the first transmission? Maybe caught in the tubing etc and is now clogging the radiator's trans cooler. Most of these trucks have a cooler in the radiator and an additional cooler in front of the radiator.
These transmissions are expensive so I would:
clean the radiator, blow out the transmission lines, change the external filter, drop the pan and look for more clutch material if not replace the internal filter and see what happens. This will be lost money and effort if your current transmission is going bad. It still might be worth trying. If the clutch material is going bad from the current transmission could someone have rebuilt it with poor quality material?
Awesome going to check it out got the Sam problem
Hi robert,
Very informative video
I have Allison 2200hs .my transmission is getting hot above 225 f. Mechanic said metal particles in oil . Inner cooler flow is ok. Gear Shifting is good. Mechanic saying need to change whole transmission .
My question is
Is metal particles in oil are not normal? What else make this transmission hot or heat up?
Thanks and waiting for reply
How did u clean it out?
Just bought a new one
Did changing the radiator solve the problem or did you change the transmission fluid and filter also
Changed the Radiator and ya it worked
All of the above... go from there
How hot was the transmission getting?
Going to assume smaller trucks its going to be the same deal.
Looks like someone needs new clutches.
Looks like fibres from a failing trans filter
Thats is an engine cooler? Mr tranny cooler is mounted in the front in front of the ac condenser. Those lines you showed are engine oil lines. My truck is an 03 duramax. With the allison
Not engine oil lines transmission oil lines
No this is your main and first trans cooler the one up front your seeing is our aux transmission cooler hense all duramax and 8.1 with the ally’s have these two (2) coolers