70 F100 Transmission problem

Sounds like the clutch is slipping if I understand you right. You said "engaged" which I am assuming to mean pedal pressed down. In actuality the clutch is engaged when the pedal is released. Anyway, if you get the truck moving in first gear ant the give it some gas (step on it hard) and the RPM's go up but the truck does not "jump off the line" like it used to then the clutch is slipping. If this happened all of the sudden, the pressure plate springs are probably breaking loose. If you have a lot of miles on the clutch then you it is probably just worn out and needs to be replaced. In any case, a clutch job replaces all of the same parts and should solve your problem. There is one opinion to get it started. Maybe someone else will have some other thoughts.

Tim .

Sounds kinda like the clutch is slipping, but I'd expect the RPMs to climb as you attempt to accelerate and you'd soon start smelling burning clutch.

Might be a sticking throwout bearing causing the clutch to engage in "slow motion".. Is this a mechanically or hydraulically actuated clutch?? If the former, make sure nothing is binding - might be a bad cable. If the latter, try flushing the system.. might have some "gunk" in the hydraulics that's not allowing the slave or master cylinder to release.

Barring problems with either of those, I'd take an afternoon and install a new clutch, throwout and pilot bearing and get the flywheel resurfaced.

On Tue, 15 Jun 2004 10:21:56 -0700, Rob rearranged some electrons to form:

What Tim said. Sounds like the clutch is slipping. Have you noticed any oil leakage? If oil gets on the clutch lining (from a leaking rear seal for example) then that's going to be a problem.

Thank you all for the quick response. I do have an oil leak in the engine that has coated the transmission case and surrounding areas. The truck only has 130,000. Is that a lot for a clutch?

I suppose a clutch job would probobly solve the problem.

I've seen clutches killed in an afternoon and, I've seen others go well beyond 200K miles. It all depends on load and driving style with a bit of luck thrown in. When you get the clutch done, make sure you have the release and pilot bearings replaced and, have the flywheel resurfaced. If the trans is noisy, it may be ready for an input shaft bearing which is generally a problem with only overdrive transmissions. Most major cities have clutch specialty suppliers that can rebuild your old clutch and surface the flywheel for you. IIRC, the 435 is a heavy transmission which may require a second pair of hands to handle it. You will also need to get the correct disc alignment tool. If you are limited on mechanical experience, ability, and tools for the job, you are probably better off to farm it out to someone who has done it unless you have a very good friend who is willing to make up for what you don't already have for the job. You should also get the oil leak repaired. It sounds like a bad rocker cover gasket or a bad intake manifild gasket. The rocker cover is easy - the intake can get complex for a newbie with limited resources.

On Wed, 16 Jun 2004 12:08:05 -0700, Rob rearranged some electrons to form:

If you don't fix the oil leak and it gets on your new clutch lining, you will have to replace it again.

I assume release = throwout here. An easy way to remove the pilot bearing:

Pack the inner hole with grease until the entire cavity behind the bearing is full. Take a piece of dowel, metal rod, drill bit etc that JUST fits into the center of the bearing. Tap it with a hammer. The grease will press the bearing right out. (If ya use a drill bit, the chuck end goes in the bearing and you can tap the sharp end with a brass or plastic hammer with no damage to the bit) Just clean the grease off everything thoroughly before you start putting it back together.

A chunk of broomstick works just fine for this. Not as "accurate" as the proper pilot alignment tool, but it'll get ya in the ballpark. I've done 6 or 7 clutch jobs with the old broomstick trick. You just have to go slow as you're moving the tranny back into position and you can't fully tighten the pressure plate until it's all lined up properly.

Might be a rear main seal too. I've had to replace a couple of those on my 4Runner.. Not difficult, just very involved and time consuming. Same with an oil pan gasket. not hard, but involved and time consuming.