Stock 4L80E WOT shift points

[millsroger]

Per sig. '94 L65HO/4L80EHD. Totally stock engine and trans, I think. A bit worried about the RPM at WOT shift. In all gears it shifts at 3750. That's in the shaded red on the tach and above the spec for max RPM for the engine.

Shifts are solid, TCC locks firm in both third and fourth at WOT. Full stall RPM is 1600. Wondering what others are seeing for max shift points.

 

[THEFERMANATOR]

Should be about 3200, but don't be to alarmed as your stock ECM will cut it off around 3250-3300. Sounds like you have the wrong pulley on your alternator as the tachs in the 6.5's are driven off the alternator. When you replace your alternator with an aftermarket one, you will get a gasser pulley which is smaller and makes the alternator read high by about 10-15%.

 

[millsroger]

Thanks Ferm. I am sure that you are right!!! Maint. logs that came with truck shows a new alternator last year. It also might explain why the tensioner is very near the end of travel--smaller alt pully. Will track down the right pully--any ideas who might carry just the pully????

 

[THEFERMANATOR]

I know if you search there is some info on it. I can't rememeber right now, but I want to say it is a 52 MM pulley that the 6.5 needs.

 

[millsroger]

Now that doesn't make sense--one that's on there is amost 60 centimeters. If it needs to be bigger it shure can't be 52 milimeters.

 

[ak diesel driver]

http://www.thetruckstop.us/forum/sh...-stumped&highlight=alternator+pulley+diameter

 

[millsroger]

Sorry, I mean to say 6 cm. Per the link, small is 2 7/16 or about 63, large is 2 5/8 or about 70. Mine is 2 1/4 or about 60mm.

 

[THEFERMANATOR]

Now that doesn't make sense--one that's on there is amost 60 centimeters. If it needs to be bigger it shure can't be 52 milimeters.

I couldn't rememebr the specs off hand at the time, for some reason I thought it was 52 MM for a diesel. I see AK found it for you though.

 

[3500GMC]

Good catch on the pully...