No power in 48re reverse or Manual 1st

[dsldude]

This has been the case for a while on this truck since I had the transmission replaced. Basically if I backup to a small object, say a 2x4, hill, or a small curb, let the truck stop on it and try to power over it in reverse, it will not go. It spools, smokes, etc, but wont power over the object. It almost acts like I have the brake applied. It does a little better when fluid is cold in the AM. Worse when hot. It does the same in manual 1st. In drive, it will rip right over it. All the forward gears work flawlessly in drive. No boost leaks. I am assuming rear band needs to be adjusted. I am hoping it's nothing worse than that.

 

[Motorhead]

Just a question... Did you go to a tighter, lower stall speed torque convertor when you had the trans built?

 

[dsldude]

I want to say it's around 1800 stall?

 

[JKosten]

This chart might help:

 

[04.5inline6]

Adjust your rear band. i suggest removing the valve body to be sure it gets adjusted correctly. the band should be sloppy loose, almost to a point you think it’s too loose. Spec is torque it to 72 inch pounds, then back off 2.5-3 turns. I have built several transmissions, and i always back mine off more like 3.5 turns. If the band is too tight, it drags on the reverse drum that it goes around, and wears the band as well as the drum. It happened in my personal truck, which is an 04.5. I put in a new drum and rear band and backed off until sloppy loose. works great no matter the weight i’m pushing backwards. Over 450 horsepower and 35 inch tires pushing 15k+ pounds and it has done great.