ok well i jst swaped to the 80e, now the trk is slower off the line than before i did the swap, with the 3.42, i have a set of 3.90 n trutrac i was gonna use with the old setup. wouldd 3.90 improve the performance? or should go with a lil bigger gear, i think my tire is 31.5 tall, i'll recheck. its my DD n i do crosscountry trips.
gracias,

 

If your tires are indeed that tall, then 4.10 or 4.30 gears would be better suited for your truck imo.

 

no I just rechecked tires are 30.5....

 

with that tire and a 80e, id say 4.10s would be a dead on match..

 

i have 4.30s and its a bit much... 2500 at 75 with a 30" tire... i would do 4.10s.... its def going to help...

 

is their much difference in the driving between 3.90 and 4.10, perfromance, mpg, towing?? i already have the 390's and i dont want to spend more $$ if theirs isnt much diffrence.

 

Most people wouldnt be able to tell the difference SOTP between 3.90 and 4.10's.

Just remember that the 60e/65e/70e has a 0.70:1 OD ratio while the 80e/85e has a lower 0.75:1 OD ratio, which is roughly 200rpm difference on the highway.

To get your low speed acceleration back, I suggest a higher stall TC, as if you regear to get your low speed acceleration back, highway revs will be too high.

3.90's would be a good all aroudn gear for you, so would 4.10's. I vote 3.90s as you allready have them.

peace
Hog