68rfe health and tow/haul mode

[GunnerJ]

First off, this is not a thread asking if tow haul is bad for your tranny and when to use it. In fact, I have a theory that having T/H on all the time is better for the tranny in all uses. The 68 rfe behind the cummins is known to burn up the overdrive clutches due to a lack of line pressure and also because it shifts into those overdrive gears too early in the name of fuel mileage. Correct me if im wrong, but T/H increases line pressures, and I know it changes shift points to higher RPMs. So to me, it would seem that always have T/H on would in fact make your tranny last longer due to the increased line pressures and kicking into the overdrive gears later, thus preventing the overdrive clutches from being burned. In my "field tests" my fuel mileage has not actually dropped a significant amount, at least nothing that couldnt be explained by other variables. Your guy's thoughts?

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[69GWC]

When I had my Cummins it was allways in TH mode just for the reason you said.
Then I had the trans tuned and if you want a better driving truck having the trans tuned was well worth the 3 bills it cost.

 

[GunnerJ]

When I had my Cummins it was allways in TH mode just for the reason you said.
Then I had the trans tuned and if you want a better driving truck having the trans tuned was well worth the 3 bills it cost.

What trans tune did you run? Ive been looking at EFI live with rev max trans tuning but i worry my tranny isn't up to the task being high mileage..... and built by dodge

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[69GWC]

I had a tune from Dragon Diesel ( think thats right) plus I ran 100hp tune with a 2nd gen SS header and 465 Turbo.
Having the transmission tune made a huge difference on how the truck drove, no more 6th gear and 40mph crap it would not shift into 6th untill 55mph.

 

[GunnerJ]

I had a tune from Dragon Diesel ( think thats right) plus I ran 100hp tune with a 2nd gen SS header and 465 Turbo.
Having the transmission tune made a huge difference on how the truck drove, no more 6th gear and 40mph crap it would not shift into 6th untill 55mph.

That is the way my truck is now, i have a 100hp smarty tune, full deletes, and pedal commander, and it will not shift into 6th until 55mph. I would love to build this truck but i know the tranny wont hold it unfortunately

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[Jimmy07]

Correct me if im wrong, but T/H increases line pressures, and I know it changes shift points to higher RPMs.
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It doesn’t increase line pressure. Only changes shift points.