The Stovebolt Site Forums The Shop Area Engine Shop Clutch/drive line shudder

I need some help, My 53 3100 with 350, 4sp, and 3.41 rear axle has a "shudder" when ever I try to reverse. I though maybe the pinion angle might be the problem, so added 2 degrees today and no change. I have new motor mounts, new u-joints and transmission cross member. I haven't checked the tranny mount yet. Anybody else had this problem, and know of a fix. I appriciate any input. Thanks.

Just a little oil in the bellhousing can cause problems. Do you have any drips from the flywheel area? The rear trans mount is the most likely problem, though.
Jerry

I know nothing about a 350 but my 235s 1st-gear and reverse chatter was eliminated after have the flywheel resurfaced (no rear oil leak in mine).

what Tim said - someone got a greasy hand print on the flywheel during assembly

Bill

Tim,
did you install a new pressure plate at the same time? I am having a chatter problem with mine right now and it has a new disc and it is dry. My third attempt at stoipping the rear main leak worked when I replaced the main bearings, which were really worn.

I replaced every part of the clutch assembly in the '54 235 in my Suburban (and the pilot bushing), even though the old clutch disc, pressure plate, and throwout bearing had less than 5,000 miles on them. I took no chances. A friend is now using those parts with no problems. I have put that clutch assembly and pressure plate behind the '60 261 that is almost ready to fire up in my Suburban (the oil pressure in the old 235 was at zero at idle and at 5 psi when cruising).

My 235 flywheel did not look grooved but it was glazed and heat-checked. NAPA resurfaced the pressure plate for $40. The clutch assembly cost about $150 (2005) at Advance Auto Parts.

Did you mic your bearing journals on the crank or just replace the bearings? I am asking because this is what I might do with my 235 (which ran quiet and smooth and at 18 mpg). Did you remove/drop the crank to replace the rear seal?

Yes, I did install new clutch kit and I'm quite sure the rear seal isn't leaking. I would think that it would shudder in 1st & reverse. No I never had the motor was never torn down. No I didn't have the flywheel machined. No I didn't change the pilot bearing. I really appriciate the response to my question. Thanks,

When I did my in-place rebuild a number of years ago, I was able to remove all the shims on the mains without causing any drag. It would have been prudent at the time to investigate further, but I didn't. The 216 ran nicely and had no bearing knocks. however, after a few hours of running, the nice dry rear main area started to leak like a tap. A few months back I replaced the seal with one of the new type from Best Gasket (made from a teflon weave) and it held up great for about 100 miles. I had to drop the crank some to do the install and that included removing the transmission. Well, finally on my last attempt, I installed new main bearings as outlined in the manual. At the same time I installed an NOS rope seal. My shimming results showed that I had more wear on the rear most bearings. The rear main required about .002", that is .002 on each side and it progressed to the front main where I used .004" in shims or two .002 on each side. The seal has been very good ever since that repair.

My oil pressure really wasn't my main concern. On the highway at about 2200 RPM, I have a little better than 7 lbs pressure. I am using 20W50 and a 160 deg. thermostat. I know that pressure isn't stellar but it is OK. I think my cam braings are fairly worn but they don't give me any trouble. I treat the motor with the respect due to it's age!

I forgot to mention that before I replaced the main bearings, I took the cap off one of them and inserted two stacked .002" small pieces of brass shim between the crankshaft and the bearing. After snugging up the cap there was no extra drag observed. That bearing was operating with at least .004" clearance without any knocks.

Just an idea,
When the flywheel is surfaced, have the rear surface, the one that mates to the crank end surfaced also, had the same prob and this cleared it up for me. You may need shims there after.
dg