Bilster

iTrader: (21)

I put a 5.3/T56 combination in my 1998 Ford F150. The factory 4.2 V6 was dead when I purchased the truck already knowing I wanted to do the swap. I made the front motor mounts and modified the Ford transmission crossmember for the T56 pattern. I had to add a 3/4" aluminum shim to get my driveshaft angle correct. Generally speaking, I have been very happy with the swap but it has always had a rear end shake upon braking. I replaced the front rotors/pads. Added new Earls stainless brake lines then new drums/shoes to the rear. I disconnected the ABS thinking a bad sensor might be causing the shake. I even took the entire rear end of my 1997 F150 which works perfectly. I replaced the rear springs and added Bilsteins all the way around. The truck drives amazing but.....still has that rear end shake. The only part that's old and rather worn is the bushings in the rear hanger. Now there is no vibration upon acceleration or cruising. What else can I look for? Worn transmission mount? Driveshaft phasing is incorrect? I need ideas.

Project GatTagO

iTrader: (7)

Is it under braking or just decelerating?

Andrew

Bilster

iTrader: (21)

Just under braking. If I get on it hard during acceleration and break the tires loose, it doesn't even wheel hop. So that's was so confusing. It's hard to diagnose because there is no other situation other than braking that causes the condition.

Project GatTagO

iTrader: (7)

If it is only happening under braking then I would think it is a brake problem and not a driveline problem.

Andrew

HILROD

I've had a few different vehicles get out of round drums. The cheap offshore drums run true on a brake machine and jump all over when bolted on.

Bilster

iTrader: (21)

But the rear end I installed worked perfectly in the truck I pulled it from. I did nothing but install it. No brake work. So maybe the way the brake fluid is modulating??

Old Geezer

iTrader: (3)

Accel = pulling on the bushings. IE, steady load.
Braking = reverse direction loading.
May be the cause???
Why not change the bushing if, as you say, are worn??

Bilster

iTrader: (21)

Found the problem.....
I bought a used T56 and the bushing in the tail housing is badly worn. Time for a total rebuild as the trans is starting to pop out of gear when de-accelerating in second gear.

Thanks everyone for your input.

BigEd_72455

iTrader: (7)

Where is the build thread for your truck build? I am beginning a 97 F150 swap and am looking for info on engine mounts and trans mounting.