48re Issues

W

waparson

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May 11, 2015
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Did a 48re swap on my 08 6.7. From the beginning it never really shifted all that hard. It was a firepunk comp2, bought used (why I'm not complaining to fp about it) But was rebuilt due to a shaft break, was rebuilt by firepunk and had paperwork and new TC in box and everything strapped to the pallet still.

Ran for a while, burnt up the clutches due to I didn't have enough cooling and ran up on me pretty quick at the track.

Had it rebuilt by a reputable shop, new TC, all clutches, etc.

Afterwards, shop said line pressure was low. Would be around 140 when they thought it should be 190-210. Tried to adjust it by the screw and drilling, no change.

Swapped VB from a known working tranny, adjust pressure, and it was at 190. Test drove it and it was around 140 driving around and would jump up to 190 and hold. Went to get on it once and it worked perfect, held pressure and everything.

Went to get on it again, wouldn't shift into 2nd and just revd up. Could let off and continue on normal and it would shift, but was now a very soft shift. Could immediately see a drop on the gauge, in overdrive it was only around 140 or so when it was 190.

Can't seem to pinpoint the issue, anyone ever seen anything like this?

At this point the only thing left is the case, possibly a crack in the case relieving pressure?

Thanks!
 
So pressure is now back to 140psi max? Put a line pressure gauge on the reverse port and you should have 225-250psi in reverse, this will identify whether you have a pump issue or a vb/trans issue.

Lavon
 
LAmiller said:
So pressure is now back to 140psi max? Put a line pressure gauge on the reverse port and you should have 225-250psi in reverse, this will identify whether you have a pump issue or a vb/trans issue.

Lavon
Click to expand...

Thanks! So if I don't have 225psi in reverse, does that point to the pump or VB/trans?

Thanks again!
 
LAmiller said:
So pressure is now back to 140psi max? Put a line pressure gauge on the reverse port and you should have 225-250psi in reverse, this will identify whether you have a pump issue or a vb/trans issue.

Lavon
Click to expand...


put it on the reverse port and we've got about 280psi!!!
 
So pump is good ( that is unregulated pressure from the pump). If you have 190psi in 3rd locked then falls to 140psi in Overdrive, you likely have a leak in the Overdrive circuit. If you are just low in pressure altogether then I'd say there is a valve body issue. Let me know if you need any help.

Lavon
 
LAmiller said:
So pump is good ( that is unregulated pressure from the pump). If you have 190psi in 3rd locked then falls to 140psi in Overdrive, you likely have a leak in the Overdrive circuit. If you are just low in pressure altogether then I'd say there is a valve body issue. Let me know if you need any help.

Lavon
Click to expand...


From my guy he's saying it would be 130 1st-3rd, OD was around 190, Lockup was 130-140. Does that say anything?

Thanks for your responses so far Lavon.
 
Transmission has been shipped to Firepunk from my guy. Can't wait to get this thing fixed.
 
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