The Stovebolt Site Forums The Shop Area Engine Shop 'Member Me and My 235?

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I just had my 235 rebuilt for the third time in 2 years and had a Tremec 600 installed. Everything works pretty good, but I've got an oil leak that I want to talk about.

Sitting on a flat surface, I get no leaks from the engine. After starting and driving the truck out of the garage onto my 15% sloped driveway, it leaks. After about 8 hours, I have a spot the size of a tea cup (2-3"). It appears to be coming from the back of my Offy valve cover gasket. Now, the guys that built thing know a thing or two about building engines; but...

This is a 62 hydraulic lifter engine with downdraft tube. The oil filler cap is not vented.

What gives? I'm a little concerned that if I don't have the issue on the flat, but do on a slope, I'm guessing oil is pooling in the rear of the head and not draining properly back into the pan. Right? What else could it be? Do I need to vent that valve cover?

It's good to have you back Jerry.
You must have a vented oil cap.
If it's leaking at the valve cover gasket it should be an easy fix. Remove the valve cover & it will probably be obvious. If you get the gasket on evenly & have an alum. cover it should seal good. Also check the lower side of the side cover gasket. Fix the simple obvious leaks, wash it down & hope there is no serious leaks.

Hi Jerry. Holy cow man, it it ain't one thing it's two, huh?
At a 15 degree slope to the rear it could come from several places but it it's the valve cover or side plate then there must be tell tale traces to guide the way. Have you checked the rear pan bolts? Mine loosen up and I have to torque all the bolts every so often.

Ok. I just got off the phone with the engine builder. As I suspected, the valve cover was leaking in the rear. I'm sure they'll fix that. The tranny leak seems to have been caused by a problem with the speedometer gear. They claim that the speedometer gear in the dash froze up and tore up the gear in the Tremec (it's a 500, not 600). That caused the tranny to leak where the gear is located.

My question to you is; does that make sense? I don't have the truck back yet so I can't just crawl under the dash. I had the speedometer unit out a couple of years ago and cleaned it up before putting it back in. I also put in a new speedometer cable. The speedometer was working fine without any fluttering and then it just quit. There was no flopping or noise or ??? Make sense?

If it is the speedometer gear in the dash, what is likely the problem? I see that Chevy Duty sells a complete unit. Does that include the gear that may be bad? Can I just replace the gear? Do I need to tear into it before I can start ordering parts or do you know what I will need now?

Thanks for the help.

Jerry

no - there isn't a "gear" in the dash unit, it's a simple magnet that spins and pulls another piece, no mechanical contact between them - if the magnetic part siezed something like the speedo cable might break by winding up, but I'd be really suprised if it siezed, and not likely anything on the top could damage the gear in the trans because the cable is a 'weaker link' .... and if the trans gear is lunched, there's no reason that should make it leak if it's fastened in properly .,.. check the speedo cable itself, if it's not buggered the likely reason the speedo quit is the trans gear problem, which happened on it's own or because they didn't have it properly held in ... the other thing that can happen to those TF speedos is the nylon gear that the magnet drives strips and stops turning the numbers

Bill