I'm looking into getting the dog 3.55 gears out for a gear that will bring the truck to life a little. I have 30" tires and the 45rfe. If I got the 545rfe tcm and 4.56's I wouldn't hit 2000 until 60 according to a calculator I tried out. Thats not bad at all. 4.10s w/o the tcm would put me at 2000 at 58mph.

Would 4.56 gears cause the trans to lock into OD sooner or would it still happen around 45mph. Im rarely ever on the highway. Also have the 9.25 Trac Loc btw.

Would gears improve part throttle acceleration up to say 45, 55mph? I feel with the 3.55s the truck is a slug.

 

I wish more axles supported the 4.30 gear. It's a perfect gear for many vehicles with the newer, steeper overdrives, where 4.56 is too deep but 4.10 leaves some on the table.

You'll be happy with the 4.10's even without the TCM swap.

 

Definitely. 4.30 would be the way to go if it was available..sadly only the ford guys have that option. I'd even consider 3.92's and just do an axle swap. I might try to find another truck like mine with the 3.92s and just test drive it.

 

Bump with questions

 

Bought a 2002 cherokee tcm, shifted noticeably smoother. Loved it except for 1 thing. TC lockup at 50 sucks. And if i was in 5th, slowed down to 50 or 52..it would remain unlocked til 55, and shift into 5th, skipping 4th.

Are 3.55's affecting the tc lockup speed? Would it lockup sooner with 4.10s? I put the dodge tcm back in. Locking up at 45 again. I wish it locked at 35 instead like it does with OD off. Takes less pedal to go.