got 77 250 and recently noticed while driving that when I give it gas there is a delay to the rear wheels, in other words when I step on the gas the rpms rise but there is a delay to the rear wheels. I was assumeing this was a clutch issue. but this morning there was a 2inch spot of fluid leaking from the transfer case.

what exactly is going on here?!

thoughts?

 

what transmission ? and is the transfer case married or divorced ?
clean the outside of the case to determine where it's leaking from .. Pictures are always helpful

 

4 speed tranny, the transfer case is divorced. Im not sure if im dealing with a clutch plate issue or if this could all be traced back to the transfer case.

I am by no means a mechanic, but I do find it odd that I just recently started to notice a delay/lag in acceleration and now the transfer case is leaking.

In no way dose the transmission slip or kick or do anything weird. it shifts perfectly and the clutch seems to work fine. the transfer case fluid smells something awful!

could the transfer case be related to my delayed acceleration issue in any way? or is it almost certainly the clutch?

 

Gear lube has a high sulfur content due to the high pressure and shear forces on the lubricant (doesn't foam either).... smells like rotten eggs, right? That's normal... learn to like it.

 

interesting, how exactly do I know if I have a full or part time transfer case?

im pretty sure its part time because the drive shaft fromt he transfer case to the front diff is spinable while not engaged for 4 wheel drive...

 

Make sure you've taken all the Free travel out of the clutch linkage .. Probably need a second person to operate the clutch pedal while you shine a flash light into the bell housing with rubber boot slid back so you can see .. Then adjust accordingly .. I don't think T-case leak is related

Also make sure the clutch fork return spring is connected properly and has adequate tension

 

yeah its part time, dang I thought we might have had a simple solution to a big problem

 

Sounds to me like a clutch that's very worn or maybe oil soaked.
If oil leaks from engine rear seal, it can't usually get to the clutch disc because of the flywheel which is solid and tends to throw oil away when running. If oil leaks from rear of intake manifold or oil sending unit or gage fitting (behind intake manifold .... mine did this last year when the plastic 22 year old oil gage line started to leak at the fitting where it's "tee-ed" in with the stock sender unit, I had to cut a little off and apply a new 1/8" brass ferrule and simply reinstall, easy fix.) it will follow down the rear of the engine and bell housing and drip off the bottom looking like it's coming from inside, but it's not.
If that oil drip is transmission lubricant though, it's coming out the sleeve that covers the transmission input shaft and upon which the throwout bearing rides on, and it means the front seal is leaking .... and that can get to the clutch disc very easily.


When they start slipping it's most often when in higher gears which makes it harder for the clutch to accelerate the vehicle with the engine. They may still pull great in low gear while slipping like crazy in high when the go pedal is trounced upon.

When I was a "young toad" ... say early '70s .... a buddy had a '71 GTO with 400 and 4 spd and 3.55 rear that ran like an older high compression motor rather than the 8.5 that it was .... and I recall a time when it would spin in 1st, spin more when 2nd was grabbed, just "nudge" like in 3rd, and 4th sounded like the engine was running loose. You could just "nail it" in first and it would spin the G70-14 Tiger Paws and fishtail, but just "nail it" in upper rpm in third and you'd hear the engine pick up rpms but no "thrust" in your back and in 4th, you'd swear he had his foot on the clutch. That clutch lasted just barely babying until he and I put a new Brute Force clutch in it (out of warranty).

Transmission gears and rear end gears multiply torque, torque is what you feel moving the truck. In "round numbers" just to illustrate and ignoring frictional drag .... if the engine makes 300 ft lbs at 2500 rpm and the clutch is in such badly worn shape or oiled that it can only transmit 200 ft lbs and the torque needed to break the tires loose is 200 ft lbs at the driveshaft or 840 ft lbs at the rear axle and it has 4.10 rear gears .... then the clutch should pull hard enough in low or 2nd to the limit of traction, but 3 rd is getting "iffy" and 4th gear where the trans ratio is 1.00:1 and no multiplication is made, the engine's 300 ft lbs at 2500 easily slips the clutch.

'77 F250 with 4 speed with manual lockout hubs has a big robust super stout NP205 transfer case, the input shaft seal and both output shaft seals and two shift rod seals and a gasket I think would fix that .... but while it's maybe leaking some .... it's not the source of your driveline slippage. My NP205 has been leaking for 20 years .... I check it's level .... top off .... and figure it's not gonna rust from outside anyway. I can park it on concrete and never see a drop so it ain't but so bad, just bad enough that it looks wet, but then I've never cleaned it off?