Clutch slipping?

Recently when in 4th gear and accelerating up hill, my rpm’s and speedo will be working in tandem normally and then the rpm’s will suddenly skyrocket from 2-2.75k to 4k-5k while my foot is on the gas, then drop back to 2-2.75k. To the best of my knowledge this has been well after shifting in to gear while the clutch is not engaged. If I am pushing my truck up a significant hill in 4th I have the gas pedal to the floor consistently and my rpms will top out below 3k. Could this sudden spike in rpms be a symptom of a slipping clutch or something else?

Here are some other symptoms that may or may not be relevant:
• The truck sometimes pops out of first gear dramatically but doesn’t stall. I’ve replaced the shifter bushings and it did not change this. This symptom has been happening for years. I assumed it had to do with a shifter fork.
• At least one if not more leaking input and output seals along the trans/t-case I am about to replace.
• slow loss of transmission fluid/gear oil, doesn’t shift as smooth as it could because of this
• cleaned the throttle body fairly recently when I replaced the VCGs
• there are some cracked flexible charcoal canister vaccuum hoses with slow air leaks

thanks for any help!

 

It sounds like you need a new clutch.

 

Yes that sounds like exactly what it is, been there, done that a couple times. Be sure to change out the pilot bearing too, bonus if you change out the slave cylinder.

When it starts to slip it's a good idea to back off it a bit, maybe even down shift and granny it up the hills. You're generating hella heat and can damage the flywheel and it will have to be resurfaced or replaced.

 

what's yer mileage, OP?

 

247k on the original clutch

 

You might need a new clutch. I have 262000 on mine and still original clutch. Damn thing is bullet proof. You made out pretty good getting that mileage out of it.

 

if only that pilot bearing was 'bullet proof'

 

Ordered a Pressure Plate, Friction Disc, Throw-out Bearing & Pilot Bearing from Aisin. Thanks yall