Allison 6sp: Transmission Overheating

Bako_Dmax

Bako_Dmax

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Apr 3, 2008
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Bako
This sucks, I got my problem with the C1s not being applied correctly finally on the third try of pulling the trans. The trans shifts beautiful now, However it overheats now.

Now here is the weird part. I did all the normal stuff that might cause overheating changed both filters and checked slippage in the converter everything good there. Still overheats, so now I check the cooler after been driving a while return line cool to the touch. Cool its plugged no big deal I take it off blow it out with compressed air and the air flows w/o a problem.

Ok here is wher it gets interesting, when the truck is in neutral or park the lines to and from the cooler are hot and everything is flowing. Now I drive the truck around jump out the cooler is cool along with the lines. Shortly after putting it in park I can feel it quickly begin to warm up and start flowing again.

The flow seems to stop when driving, the truck shifts perfect converter locks perfect. What could be goin on?? It seems to do it once the converter locks cause if im in stop and go traffic the temps hold or come down.

Im sure whatever it is will require me taking the stupid thing out again.:mad:
 
Bako_Dmax

Bako_Dmax

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Apr 3, 2008
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Bako
I see no one has any input. Well I thought it was just when the converter locks but its whenever its in gear.
 
Mike L.

Mike L.

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Acoombs said:
I see no one has any input. Well I thought it was just when the converter locks but its whenever its in gear.
Click to expand...

It's hard to have an input when we don't know what you might have done inside. You might have a sticking converter flow valve or a lube valve in the pump. Make sure you are not overfull. How hot is it getting?
 
Mike L.

Mike L.

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Acoombs said:
This sucks, I got my problem with the C1s not being applied correctly finally on the third try of pulling the trans. The trans shifts beautiful now, However it overheats now.

Now here is the weird part. I did all the normal stuff that might cause overheating changed both filters and checked slippage in the converter everything good there. Still overheats, so now I check the cooler after been driving a while return line cool to the touch. Cool its plugged no big deal I take it off blow it out with compressed air and the air flows w/o a problem.

Ok here is wher it gets interesting, when the truck is in neutral or park the lines to and from the cooler are hot and everything is flowing. Now I drive the truck around jump out the cooler is cool along with the lines. Shortly after putting it in park I can feel it quickly begin to warm up and start flowing again.

The flow seems to stop when driving, the truck shifts perfect converter locks perfect. What could be goin on?? It seems to do it once the converter locks cause if im in stop and go traffic the temps hold or come down.

Im sure whatever it is will require me taking the stupid thing out again.:mad:
Click to expand...

The trans will make heat when it is put in gear because that is when the converter begins to work. The trans should not make any heat in nuetral or park because pressure has dropped and nothing is going on to create any heat.
 
Bako_Dmax

Bako_Dmax

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Apr 3, 2008
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Bako
Fluid is at the proper level. C1-c4 has alto power paks, pump has been shimmed and a converter valve and a transgo Jr.

If I put the truck in drive with the e-brake on the cooler and return line will stay cool, as soon as I put to nuetral or park it immediatly gets hot. I pulled the line and there is a singnificant loss of flow through the lline when put into drive. The transmission shifts fine on a 550hp tune. Is it worth taking the valve body out and running through it?

Ive had no problems like this until now after I fixed the lip seal on the c1 piston.

Ive had all the pump mods and power paks installed for about 20,000 miles.

WHen cruising down the freeway the temps will gradually rise once it got to 225* I pulled over and put it into park and it quickly cooled down.
 
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Bako_Dmax

Bako_Dmax

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Apr 3, 2008
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Bako
When I first dug into the trans I got the TTS 6-speed kit. SO it has the the pump mods supplied with that kit.
 
Mike L.

Mike L.

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I'll bet you have the wrong size spacer in that valve. We had some overheating problems with the late Transgo valve untill BIG DIPPER and I fixed it last year with a longer spacer. This could be your problem.
 
RENODMAX

RENODMAX

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Mar 4, 2008
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Id guess it was in the pump if you arent having any shifting issues. On a side note I think everyone doing DIY trans stuff should really document what they do so other people can help. You left out that you have the TTS kit which is kind of important. The more people know the more they can help :hug:
 
Bako_Dmax

Bako_Dmax

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Apr 3, 2008
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Bako
What goes on in the hydraulic system and pump when going from neutral to drive? Im going to pull the trans out. What to look for when its out. What would cause flow to the cooler to stop when put to drive then immediatly pick up again when in neutral/park?

And one more question, is it a bad idea to put a second cooler in union w/ the factory one? Or is it best to just ditch the factory for a larger aftermarket cooler?
 
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