Peva

1985 F150 4.9L, 4 speed granny tranny, short bed

I bought it about 7 years ago. It's always had a clutch chatter when starting off - dashboard bounces up and down. I had the clutch (and throw out and pilot bearings) replaced 3 years ago. I asked them to check the condition of the flywheel surface when they had it apart, and they said it looked fine. I know that doesn't prove it's OK. The problem does persist with no change after the clutch job.

I suspect one or more motor/transmission mounts need replacing. I have no reason to believe they have ever been replaced.

I jacked up the engine to put tension on the mounts (front bumper raised 5 inches - so pretty sure I was more than just taking the weight of the engine off the mounts), but the mounts apparently have hard limits that don't allow much stretching at all. I did see some indication of separation all around at the edges of the of the driver's side mount with the engine jacked up (but I'm not convinced that that necessarily is an indication of the overall condition of the mount).

Here are my questions:

1) Is my observation that these mounts are very limited in their travel before hitting hard stops correct (in other words, true of known good mounts), or is the fact that they don't give much at all an indication that mine indeed need replacing?

2) Are there any particular brands of mounts to avoid or to try to get? The common brands I see are Anchor, Westar, and DEA, all at $10 and under each at Rock Auto. Then there's a Pioneer brand at about $15 each. Does the additional $5 for the Pioneer give a significant bump in quality, or are any of the $7-$10 brands in particular known to be decent?

3) Other than going ahead and replacing them to prove it, any advice on how to prove for sure that my mounts are or are not the cause of the shaking at start off?

Any advice will be much appreciated.

Braggs

Motor mounts are made out of rubber which deteriorates over time. If you haven't replaced them before, replace them. They're likely 30+ years old. As for brand, just get what the local box store sells. They'll work fine and it'll be pretty cheap. If they break (happened to me before), it'll be under warranty and replacement parts will be free. When the "hard limits" break, then you'll notice the engine will move under torque (happened to me).

If the transmission mount is torn (happened to me also) the transmission will raise up under torque with a noticeable movement in the gearshift.

Peva

Thank you, Braggs. Or I should say thanks *again* - you also helped me with info. in my steering linkage thread: https://www.f150forum.com/f13/lookin...nkages-345880/

At around $30 total for all three with shipping, I think you're right. We'll see if that fixes the pseudo clutch chatter problem.

Funny you mention the local stores. Advance has the exact same motor mounts for $25 each that Rock Auto has for right at $7 each (and tranny mount for around $5 vs. $12). That's a ridiculous difference even after paying maybe $10 total for all three for shipping from Rock Auto.

I'll probably go with Anchor brand. Seems to be the most commonly sold brand, so I guess that means that they can't be *too* bad, though aftermarket parts seem to be a real jungle for judging quality these days, especially for parts for older vehicles.

Braggs

Everything is usually more expensive than Rock Auto. I have bought a few things from Advance before after shopping around. They have some promotions on their website occasionally (free shipping, discounts, etc) and some things you just can't get from rock auto (batteries).

Peva

Yeah, I used to always check for Advance discount codes. That used to make them a good deal many times on the price comparisons. I've noticed in the last 3 or 4 years that their prices have gone thru the roof, so they're generally not a good deal even after the discounts. The discounts just end up being a marketing gimmick that waste your time. $25 vs. $7? No discount is going to make that a better deal.

Yep - for batteries - Advance, but only with the discounts. Their prices start out way high.

Peva

Well, I installed the 3 mounts. Still have the clutch chatter.

This is the granny 4-speed, and it only chatters when I start out in 2nd, which I almost always do. Starting out in first seems like such a waste - literally less than a second in first and tops out at about 5 mph, and you're ready to shift to 2nd! 2nd is very similar to first in most manual trannies - only slightly taller. I guess I just need to start using first to start out.

The good news is that I replaced all four shocks - put heavy duties on the front, and that fixed the roll steer. The remaining slight squishy feel in the steering I'm sure is due to the tall tire profile that we don't have in today's cars. Also, I think the power steering in that era was too strong, and doesn't give you any feel when turning - you know what I mean - you can steer with one finger. Anyway, overall much improved and acceptable. Feels much firmer. Probably as good as it gets.

Daniel Black

Hi, with my 1983, 300, granny 4-speed I always take off in 2nd gear. 1st is a waste of time. I had the same clutch chatter that turned out to be a bad input shaft bearing on my NP435. Also, if your truck is a 4x4, where did you get the transmission mounts? Mine has 2 upper and 2 lower mounts and even the local Ford dealers can't get them. I had to put the worn out ones back in.

Peva

Thanks for that info., Daniel.

Mine is RWD, but of course could be the same problem. Yeah - I agree 1st is a waste of time, but I'll use it so as not to add wear and tear unnecessarily with the chatter. I'll probably just put up with it. I don't put 500 miles a year on it.

I may take a look at that shaft one day. I do think there's some gear oil leakage there too, and I hate leaks. I'll have to be in the mood with not a lot else going on.