Allison 5sp: LB7 Allison tranny questions

[kmb760]

Probably about 7 months ago I had the the tranny fluid drained from only the pan along with external spin on filter and i feel like im getting higher tranny temps. When I drive home in traffic on the freeway without towing with a outside temp around 90 my tranny will reach around 200 degrees. Sometimes when i get home it almost looks like the tranny is dripping fluid from the top but gets everywhere when driving.

What are normal tranny temps?
What might my leak be from?

03 GMC 2500...Edge EVO CT tuner...285/75 tires...Leveling keys...all stock for now

 

[Mike L.]

Could be overflow.

 

[NKlamerus]

I would go with overflow too, it doesn't really look "that wet"....

Then again neither did mine about a month before the extension housing split

 

[kmb760]

What might my normal operating temps be while driving freeway for 30 minutes then stop and go traffic for while with the outside temp around 90 degrees.

I was once told the tranny temp is normal to be 100 degrees over the ambient temp, but I'm not sure how true that is

03 GMC 2500...Edge EVO CT tuner...285/75 tires...Leveling keys...all stock for now

 

[THEFERMANATOR]

100 over ambient towing is normal. Empty I wouldn't expect to see much more than 160-180. If it is over full, it will run hotter.

 

[kmb760]

100 over ambient towing is normal. Empty I wouldn't expect to see much more than 160-180. If it is over full, it will run hotter.

Hmm if that's the case I seem to be running on the warm side. Using the search function I noticed maybe there could be something in the transfer lines, what would be the process to check those and also clean them out?

Thanks guys

03 GMC 2500...Edge EVO CT tuner...285/75 tires...Leveling keys...all stock for now

 

[durallymax]

Hmm if that's the case I seem to be running on the warm side. Using the search function I noticed maybe there could be something in the transfer lines, what would be the process to check those and also clean them out?

Thanks guys

03 GMC 2500...Edge EVO CT tuner...285/75 tires...Leveling keys...all stock for now

Stock trans without towing on a short trip, over 200 seems warm but is possible. Depends on what your 90* is. Wisconsin 90* and 120% humidity doesn't really help to "cool" things at all. The air feels the same at 90mph as it does standing still.

The gauges are not always right, but trans gauge usually is close. Scanner would read true temp.

Make sure your front cooler is not full of dirt externally as well.

To flush coolers internally get some cans of kooler kleen, pull trans lines. Hook one to a jug with a hose, hook the other line to the can of kooler kleen. Then keep blasting them until the fluid coming out is spotless. Usually takes a couple cans. Blast it with compressed air for awhile to push the rest of the fluid out.

 

[kmb760]

Stock trans without towing on a short trip, over 200 seems warm but is possible. Depends on what your 90* is. Wisconsin 90* and 120% humidity doesn't really help to "cool" things at all. The air feels the same at 90mph as it does standing still.

The gauges are not always right, but trans gauge usually is close. Scanner would read true temp.

Make sure your front cooler is not full of dirt externally as well.

To flush coolers internally get some cans of kooler kleen, pull trans lines. Hook one to a jug with a hose, hook the other line to the can of kooler kleen. Then keep blasting them until the fluid coming out is spotless. Usually takes a couple cans. Blast it with compressed air for awhile to push the rest of the fluid out.

Should i flush the lines that lead to and from the tranny as well?

03 GMC 2500...Edge EVO CT tuner...285/75 tires...Leveling keys...all stock for now

 

[durallymax]

Should i flush the lines that lead to and from the tranny as well?

03 GMC 2500...Edge EVO CT tuner...285/75 tires...Leveling keys...all stock for now

Thats what you will be doing, you remove the lines from the trans and flush through them, that will flush all lines and both coolers.

 

[kmb760]

Can low Trans fluid heat up the temps as well?
I just remeasured and with the tranny temp around 180 degrees it showed being at the very first hash mark towards the bottom of the hot side.

03 GMC 2500...Edge EVO CT tuner...285/75 tires...Leveling keys...all stock for now

 

[Mike L.]

Can low Trans fluid heat up the temps as well?
I just remeasured and with the tranny temp around 180 degrees it showed being at the very first hash mark towards the bottom of the hot side.

03 GMC 2500...Edge EVO CT tuner...285/75 tires...Leveling keys...all stock for now

If you are low on fluid the trans wil start flairing shifts.

 

[kmb760]

If you are low on fluid the trans wil start flairing shifts.

It seems to shift fine but all this has been with out towing as well.

Coming back from Yuma AZ to San Diego yesterday when i got back i looked under neath and seemed to have the most fluid leaking from towards the top and down the driver side. It's so hard to tell where it's actually coming from. I just hit it with some degreaser and carb cleaner to see tomorrow if i can get a better view.

03 GMC 2500...Edge EVO CT tuner...285/75 tires...Leveling keys...all stock for now

 

[kmb760]

I still can't see exactly where it's coming from but will the tranny fluid foam and and leak from anywhere if the fluid is low?

03 GMC 2500...Edge EVO CT tuner...285/75 tires...Leveling keys...all stock for now

 

[Mike L.]

I still can't see exactly where it's coming from but will the tranny fluid foam and and leak from anywhere if the fluid is low?

03 GMC 2500...Edge EVO CT tuner...285/75 tires...Leveling keys...all stock for now

No.