Allison transmission high oil temp concerns

christopherglenn wrote:
If you hit 260, dump the fluid and replace. Allison spec is 2 dump and fills a few hundred miles apart. would be a good time to pull the two hoses from the side of the tranny and blow out with compressed air (backwards). You may have friction material clogging the coolers. There are two, the primary is a oil to water in the radiator, the secondary is the oil to air in front of the AC condenser. Both need to be clear or you will cook the tranny pretty fast. There are aftermarket oil to air coolers, but at 260 you have far bigger issues - unless the existing cooler is bad.

Great advice thanks... I did get home today and cleaned out quite a few bugs out of the radiator stack and it's going in to a specialty tranny shop Monday. I'll be sure to mention the flush...

If you hit 260, dump the fluid and replace. Allison spec is 2 dump and fills a few hundred miles apart. would be a good time to pull the two hoses from the side of the tranny and blow out with compressed air (backwards). You may have friction material clogging the coolers. There are two, the primary is a oil to water in the radiator, the secondary is the oil to air in front of the AC condenser. Both need to be clear or you will cook the tranny pretty fast. There are aftermarket oil to air coolers, but at 260 you have far bigger issues - unless the existing cooler is bad.

Our 2005 runs about halfway for the most part (180-210) during normal towing... the highest it's been is about 230-235 while pulling our 12k 5'er up I-70 toward Eisenhower Tunnel and it held there, but that was the highest its ever been, and under extreme conditions (that is one very heavy and long hill). It leveled out again a few minutes after we got over the top.

Clean the cooler first, pretty easy solution.

If that doesn't fix the heating issue then you have a mechanical issue (gauge or trans).

Paul Clancy wrote:
175-198 pulling hard 10k up big grades. lmm 2009 running transynd Allison synthetic. The only time I've seen higher was when running dex6 and overfilled. I'd suspect if your over 210+ it is overfilled. Proper level is middle of hot level hatch marks at 172 deg at idle in park. Do a visual on the cooler inside the bumper hole as well.

That's what I see.

OP you're waaaaaaaaay over spec at that temp.

christopherglenn wrote:
"normal" is ambient +100 +-10. Most rebuilders say it should be filled to the BOTTOM of the hot range when at operating temp.

My gauge was showing 260f.....I guess I'm a bit out of range...

"normal" is ambient +100 +-10. Most rebuilders say it should be filled to the BOTTOM of the hot range when at operating temp.

175-198 pulling hard 10k up big grades. lmm 2009 running transynd Allison synthetic. The only time I've seen higher was when running dex6 and overfilled. I'd suspect if your over 210+ it is overfilled. Proper level is middle of hot level hatch marks at 172 deg at idle in park. Do a visual on the cooler inside the bumper hole as well.

Go to: www.dieselplace.com. It is a forum similar to this one that specializes in GM diesel trucks and Allison transmission issues. You will get a whole host of good advise.

https://www.google.com/search?q=napa+1-8721+magnetic+filter&biw=1093&bih=502&source=lnms&tbm=isch&sa=X&ei=5VSLVdWgLIa9sAXftYLYCQ&ved=0CAcQ_AUoAg#tbm=isch&q=in-line+trans+magnetic+filter

I guess first off is what's "high temp" compared to the spec's


Anyways these filters keeps the nasty's out. Especially after a re-build. You might of just circulated all the stuff the trans shop didn't get out when re-building.

Ford used to recommend to install and to take filter out after a rebuild, after first fluid change I think. (Chevy, I don't know what they think or do) I left mine in and it gets changed once a year. And makes a nice spot to also change fluid. And then Ford recommended not to use them at all because to many people never changed them until their trans blew up again, and wanted to blame re-builder.

They do have a couple downfalls that are critical to be aware of IMO.

1. Yet to find a quality hose clamp to keep it from dripping every so often. (not so big of deal to get under and twist hose clamp every once and while)

2. You have to change them. If you forget to change they could get plugged up and prevent fluid circulating and actually cause more damage. (Very big deal. If you don't change them you have actually installed a shut off valve because they don't have a by-pass mode once they get plugged up)



How I found out about these things and sold on them was at part store one day and maint guy from ambulance company was buying some. Their shop was located in back and next to where I used worked. Got talking and found out the filter is one of the things they put on their equip. Months later talking with auto part owner asked him how many of those filters he sales. He hit a couple of key board strokes and said "not many on a yearly basis, only fleet owners bother to put them on. But it's not unusual for them to get many miles on trans".

Case closed for me.

Another thing, have to taken temps with IR temp gun. Maybe gauge is off. And you could change the cooler or atleast do a "flow test".

Have you ran a magnate thru your old fluid?

(edit part...Just re-read your posting. If your taking it a shop let them screw with it)