68 GMC transmission problem
 

My sons 68 GMC pu won't go. Put it into any gear and it sits like it's in neutral. The linkages are ok and if you push it after it warms up, it'll go. Any ideas what it could be? we dumped half a quart of lucas oil into it to help and to bring the level up to normal, but it's still doing it. Any ideas/suggestions will be greatly appreciated.

Thanks

Re: 68 GMC transmission problem
 

No sure if I missed it, but what kind of trans?

Re: 68 GMC transmission problem
 

You could drop the pan, & see if the filter is clogged. Also look at the color of the fluid in the pan....if it looks like silver paint, you have a bunch of metal, or blacken than coal= burnt clutches). what trans does it have? best of luck,crazy Al

Re: 68 GMC transmission problem
 

Sorry, it's a 350 (I think) automatic.

Re: 68 GMC transmission problem
 

THE BAD NEWS IS.. I'LL BET IF YOU REMOVE THE PAN.. YOU'LL FIND A TABLESPOON OR TWO OF SILVER & BLACK SHAVINGS IN IT. THE GOOD NEWS IS THEIR CHEAP (COMPAIR TO ANY ELECTRONIC O-D TRANNY) & EASY ENOUGH TO REPLACE. GOOD EXPERINCE FOR BOTH OF YOU I'LL BET.;) YOU DIDN'T SAY BUT I'LL BET YOUR SON IS 17.:lol::lol: IT SEAMS LIKE THEY JUST DON'T BUILD T-350s THAT HOLD UP TO TEENAGERS NO MATTER HOW THEY BABY THEM..:lol: HONEST DAD ;) JOHN

Re: 68 GMC transmission problem
 

:lol::lol: I remember those days...."Honest dad , I was only goin 40 when it broke(didnt tell him it was 40 in reverse, & a slap into low for the big burnie!) Somethin tells me that that old man knew more than I was tellin him tho....;) if the old truck sat for a while, & the pan is clean of metal/clutch material, I would attemp a screen & fluid change.....might not fix the problem, but its only a little time & just a few bucks. best of fun, crazyAL

Re: 68 GMC transmission problem
 

Are you checking the fluid level with the engine running and after going through all the gears? It sounds like the fluid level is low.
Not to downplay what everyone else said, if the fluid is anything but red, it has an expiration date

Re: 68 GMC transmission problem
 

I HOPE IT'S SOMETHING SIMPLE LIKE .. A FILTER OR FLUID... BUT SOMETHING TELLS ME (MAYBE IT'S CAUSE I RAISED THREE BOYS) BUT I WOULDN'T GIVE A BUCKET OF WARM HORSE PISS FOR THAT TRANNY.S FUTURE. :lol: ;) HONEST DAD... I WAS ONLY GOING 47 IN A 55 MILE ZONE & DRIVING LIKE MY DRIVERS ED INSTRUCTOR WAS BEHING ME. ;) BTDT JOHN

Re: 68 GMC transmission problem
 

Im with you on all that John. The one trans that comes to mind is that old Power glide.....if it was full of varnish, a screen & fresh fluid would fix the problem(assuming no metal or clutch junk in the bottom). That is why I suggested dropping the pan(whats inside the pan will pretty much tell the story);) Hope for the best, but be prepaired for the worst. Dad always showed his 3 boys to take the cheap easy route 1st.....if it didnt work, then go fight the problem. I too hope the easy route works, but I am skeptical also. Best of luck,crazyAL

Re: 68 GMC transmission problem
 

I'll stand up for the kid though...
Assuming the pan is filled with silver/black sediment...
The tranny may have been in self destruct mode before your son ever laid his foot into it. While he has probably spun the tires in it a few times, unless he's been going through rear tires like crazy, I wouldn't blame him for the damage done to the trans. It's an old truck, and there's no telling how long that trans has been in service, or how the previouse owner treated it. The sad truth is, the average joe never thinks about doing a fluid and filter flush on a tranny, until the fluid is black or the trans is slipping. By then, in all reality, it is too late.
Now, if the boy has been killing tires left and right, then maybe he should fund the rebuild on his own. I'd be willing to bet he'd treat it with a little more respect after a few C-notes are spent on repairs.

Re: 68 GMC transmission problem
 

Told straight, & square;) all in all, it is an old truck, & has had countless (untold miles of abuse/no maintainence). I dont think anybody is trying to "jack with the kid".....understand that we were ALL kids @ 1 time;). my theory, is the same as the old man said it....you broke it, I will help you fix it....you pay for it, & you are gonna be azz ho,s & elbos. If the kid is into the "dream", you wont need to twist his arm......& dammit, you will both have a lot of fun;) best of fun,crazyAL

Re: 68 GMC transmission problem
 

i had a similar condition on an old mail jeep i bought from the postal service..when it was cold..started and wouldnt go anywhere..then after it warmed up enough,would go..and once hot was like normal. turned out the filter had a crack in the side where it drew it up into the valve body,so sucked air.check the fluid with the stick,if its dark and smells burned,its toast..red and smaells like oil,drop pan and check it.

Re: 68 GMC transmission problem
 

BELIEVE ME WHEN I SAY I'M NOT PICKEN ON THE KID. IF HE DROVE LIKE AN OLD LADY I WOULD WONDER.:lol: SHOOT... WE'VE ALL BEEN KIDS (SOME OF YOU STILL ARE) & THE LAST BB TRUCK I BUILT, I PUT A LINE LOCK IN & THAT WAS JUST A FEW SHORT YEARS AGO. EVEN THOUGH I'M ALMOST 52 & HAVE PRETTY MUCH LOST MY NEED FOR SPEED, I'M STILL OCCASIONALLY CAPABLE OF DOING A BIG SMOKY JOHN FORCE TYPE BURNOUT.:lol: THE DIFFERENCE BEING... I'VE GOT THREE BRAND NEW ZERO MILE T-400 SHORT SHAFT TRANNYS ON A PALLET & 10 NEW TIRES IN MY SHOP. I KNOW WHO'S GOTTA FIX & PAY FOR IT IF & WHEN I BRAKE IT. R&R A T-350 IN ONE OF THESE OLD TRUCK IS ABOUT A SIMPLE & STAIGHT FORWORD MECHANICAL CHORE AS YOU CAN FIND. GREAT MECHANICAL EXPERIANCE FOR BOTH THE KID & THE DAD. IF DAD PAYS SOMEONE ELSE TO FIX IT HE'S SURE NOT DOING THAT KID ANY FAVOUR. THERES A WEALTH OF INFORMATION & EXPERIANCE JUST A KEYSTROKE AWAY, & OVER 50,000 TRUCK NUTS MORE THAN WILLING TO PROVIDE ADVICE, INFORMATION & ENCOURAGEMENT. JOHN

Re: 68 GMC transmission problem
 

Does the steering column shift indicator have 2 or 3 forwards? 1968 pickups used the 2 speed powerglide or 3speed 400 hydramatic.The T 350 was first introduced on 1969 pickups. Regardless, it sounds like its rebuild time.

Re: 68 GMC transmission problem
 

Thanks for the wealth of info. Fluid check shows the fluid is still red. We'll drop the pan when he gets back home. Thanks again to all of you for your input and suggestions. Will let you know how it turns out.

Thanks!

Re: 68 GMC transmission problem
 

I'd be testing the line pressure cold and warm in all 4 ranges.