5spd Allison Flared Shift Questions

[TwinStick]

I recently changed jobs and I don't work from home anymore so I commute. It's been a record warm summer here in the PNW and I'm concerned about my transmission. I have an 04 LB7 with about 176k on it. The tranny runs about 100 degrees above ambient temp (this is based on the OEM dash gauge, not an aftermarket one) which I read is normal , but when it's in the 90's outside it gets to about 200F. That's when the flared shifts start. It's pretty bad traffic (90 min to go 21 miles) so you can imagine the wear I'm putting on this aged transmission. I replaced the fluid with Transynd hoping that would help, and it did lower the temps by about 10-20F but the shifts are still flared when it gets hot. These shifts are really bad. Like scary bad when it's at its worst. Then, the next morning when the tranny is cold the downshifts are very rough. Shaking the whole truck when slowing for a red light, etc.

Is this normal for a 5spd Allison with this many miles?

Is there anything I can do to fix or at least improve this?

Could it be some kind of build-up in the valve body that a fancy additive can fix?

Should I try a new NSBU switch? It also lags between R and D and the PRNDL display is blank (but I think the backlight is just burned out).

Anyone want to trade me for a truck with lower miles? ;o)

Thanks in advance for any help.

 

[Mike L.]

Was the sump filter changed?

 

[TwinStick]

I've never changed the sump filter, no. I bought the truck with 140k miles so I really don't know when if ever it was changed.

 

[Mike L.]

I would want to look inside the sump filter and see if anything is in it.

 

[TwinStick]

Thanks Mike. If I'm going to pull the pan, would it be worthwhile just to change the sump filter anyway? Whether there's something in it or not? Also, I don't tow anything heavy but a couple times a year and even then it's only about 6,000lbs. Would a deep sump pan help at all?

 

[Mike L.]

I would change it. Save the fluid in a clean bucket so you can use it over. Peel the filter open and unfold the paper element and see what's in it.

 

[TwinStick]

Bringing this back around now that the weather is warmer. It's starting to flare shifts again while commuting in traffic. Trans never gets hotter than 100F over ambient (except when I drive up to the mountain, it hit over 200F while it was 40F outside and there are some really bad shifts when I get toward the resort). Sump filter was replaced back in Sept/Oct.

Anything else I should check/replace? Trans cooler, coolant lines, etc or is my Allison just tired A/F?

Is it possible that the trans has just learned to shift like I'm in stop and go traffic all the time?

 

[Mike L.]

Is the trans stock?

 

[TwinStick]

Yes it is

 

[Mike L.]

Yes it is[/QUOTE

Then you are a dumb shit.

 

[TwinStick]

Haha. That's aggressive. So it's just tired then.