So recently I was given a 1979 f250 with a 5 speed nv4500 in front of a mostly stock 400. Originally a np435. I'm afraid the clutch is going out. For a couple of months it's made a whining noise when I push it in. recently it's started to feel like when I'm pushing it in or letting out it feels like nothing is happening and then all of a sudden it will engage. Like when stopped and trying to accelerate, I can let out about halfway with little change, then all of a sudden it seems like it engages with about half strength and it makes it kinda hard to drive smoothly. My father believes that it's because I start accelerating from a stop in 2nd gear. (First is a "granny low" with a 6.44 gear ratio, 2nd is a 3.44 gear ratio) Does that sound like the problem? 1st is very low and if I start rolling in that gear I have to shift to 2nd immediately.

Is my clutch about to die? How expensive will that be to replace? How big of a job will that be? Does anyone know what specifically is wrong and if I can replace it now before it damages something else?
Also, how do I know what clutch to buy? A nv4500 model or a 400 model? I'm sorry for all the question, I'm in dire need of help and pretty worried about this. But I'm pretty sure you guys will be able to help.

 

DL sorry I am not familiar at all with that transmission swap. Is it a hydraulic clutch? The issues of the engagement sound like the hyd clutch needs serviced? As far as the whining sound that could be your throw out bearing is about dead.

Taking off inn 2nd on a low gear trans should not hurt a thing, unless you have to slip the clutch alot to get rolling?

As far as how big a job to replace a clutch, pressure plate and throw out bearing (they usually come in a box set), you have to either drop the transmission to get to the bell housing off, or pull the motor and leave the trans where it is...

Trans shop prices can be rough, 2wd is easier than 4wd when dropping a trans though.

Maybe some trans swap guru will chime in on what to order as far as what clutch.