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Another tranny problem for you

J

jchrisk1

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northern michigan
I am new to the site and have a few questions. I signed up a couple of weeks ago and have been wearing out the search function. I am new to 4 wheels (at least the kind I have to work on) and need a little help.
I picked up a 76 Blazer with a plow from my boss and it has problems. Specifically the tranny right now. I think. It is 400 with a 205. I tried to drive it and it didn't really want to go. Seemed like it wasn't shifting right. So, I did some research here and found that the kickdown switch wasn't hooked up. Not a big deal for now. I checked the vacuum modulator and when unhooked it shifts after a long run, with it hooked up it shifts kinda.
Anyway, my boss checked the fluid while I did some other things and he said it was fine. It wasn't. I didn't even get a reading. So, I started putting fluid in. Warmed it up, shifted through the gears, nothing. Repeat. Repeat. Still nothing.
He had told me that it would leak out of the overflow on the transfer case, but I don't see it leaking. I'm thinking it was overheating because he drove it low all the time while plowing. I'm wondering if it is just filling up the transfer case and I'm not getting a reading on the dipstick yet. I'm guessing that it probably has a bad seal.
The problem is, I need to get this to my house so I can work on it. It's kind of hard to work on it when it's so far away and my motorcycle doesn't carry all of my tools. It is 50 miles from me and I'm afraid to drive it. It's shifting better, but it still doesn't feel right. Should I just keep pouring fluid in? I've already put 4 qts. in it with no reading. It's like it's the amazing vanishing ATF.

Any help is appreciated.
 
4 quarts is way low, and I doubt it would move at all that way. Possible the modulator is leaking through, and getting sucked into the engine?
 
I would add fluid until it got to the correct mark on the dipstick.

I would try a new or a known good modulator too.
 
79rustyk10 said:
I would add fluid until it got to the correct mark on the dipstick.

I would try a new or a known good modulator too.
Click to expand...
you shouldn't have to add more than 5-6 quarts, unless the trans has been completely emptied...then it would take 11-13 quarts depending on pan depth, and cooler equipment.
Are you sure you have a correct dipstick and tube for a 400?
 
Hard to say. You can put a pan under it, and take out the fill plug on the 205. If the transmission fluid is pouring into it, it will be seriously overfilled.
If it is, let the excess run out, leave the plug out, then pour in another quart into the transmission. Watch to see if it runs out the 205 fill hole.
Also, does it smoke a lot?
A busted diaphragm in the modulator can let the engine suck the fluid out like someone else here said.
Usually its just enough to soften the rubber hose from the diaphragm to the steel tube and let it fall off.
But, if its really bad, it might just be drinking it. If so, you will find the rubber hose coming off the modulator wet inside with ATF, plus lots of smoke out the exhaust as it burns it.

If its been run really low on fluid under heavy loads, then the tranny is toast. Its not ruined per se, but it will have to be rebuilt. In which case, after you get it filled it will not cause much if any more damage to drive it the short distance.

In the meantime, try to get it full, and/or figure out where the fluid is going. Don't forget that there are cooler lines running up to the radiator that might be leaking.

Plus, when you get it home, please remember that park only works when the transfer case is in gear, and the drive shafts are hooked up......

I personally know of three people who did not chock the wheels, put the transmission in park, took the driveshaft loose and wondered why it ran over them......
 
The hose on the modulator was dry when I pulled it off. So it's not leaking, and it's not leaking at the radiator.
I don't know if the dipstick and tube is correct for the tranny or not. I'm pretty sure it's not the original one though. But it could be correct. I won't be able to check it until I get it home. Or is there a way to check without pulling the pan?
I will pull out the plug on the transfer case and see what happens when I get back out there. I have a guy building me a tranny right now to replace it,so I will fill it up and try to get it home so I can pull it.
I wish I had started this before it was freezing outside.
Will any damage result from the transfer case being overfilled?
 
Will any damage result from the transfer case being overfilled?
Click to expand...

Nope, just get messy as it bubbles out the vent.
Underfilled, yes, overfilled no.

Either is bad on an automatic tranny though.

Make sure that the guy building you a 400 is aware that it is going on a 4wd and a 205 will be attached.
There are differences in the output housing.
 
One other question i have about front leaf springs. It's a 76 with 2 leaf. They are negative arched now and with the plow on it, it sits on the bump stops. Are there any other springs that I can get from another truck that will fit that aren't flat? I plan on a lift, but if I can save some money to get me through the winter it would be nice. If not, then I will put a lift on it.
 
Even with the "heavy duty" 3 leaf front springs ,my K's had the springs almost touching the rubber snubbers with a Fisher plow on it...the front springs are tapered so it makes adding any "straight" leafs hard,they will tend to want to slide out at each end..they do sell 5 leaf front springs in J.C. Whitney,but they ride like dead axles...you may get by with a pair of shocks with overload springs,I added a pair of the cheap springs that clamp over the shocks I had hanging around on my 85 Suburban that has a Diamond plow,that heavy as hell,has a snow foil on it too--it helped raise it up about one inch...the only bummer is the frames on GM 4x4s like to tear where the upper shock mount goes,and adding springs to the shocks will make that more likely to happen--I put a few thick washers behind the mounting stud to help spread the load out and beef it up there a bit..

The tranny could have several issues...if someone put a deep aluminum pan on it and didn't put a filter extention on it,that can cause troubles..maybe it had a cooler line fail and it pumped all the fluid out once (or more) --it'll take up to 10 quarts to fill the converter and pan fully if thats the case...with the modulator not connected it wont want to upshift until the engine is racing ,it wont go in second till 25 mph or more,third until 40-50 mph,and it should shift hard when it does..the filters in older TH400's plug easily with crap,I'd drop the pan and take a peek before I drove it too far...usually they whine like a power steering pump low on fliud when the filter is restricted..
 
So, add a leafs won't help? Will they slip off the sides? I was thinking about trying these temporarily.

I am just going to try and get it home tomorrow. Hopefully I make it. Then I can have time and tools to do what I need to.
 
Those are what I used,mostly because I had them hanging around since the 80's!..I had bought them for 5 bucks at a yard sale and never used them...

You can buy "Load Leveler" shocks that already have similar springs made onto them,I would say they would be better,as the clamp on ones are a bit cheesy,and may not fit all shocks,they mostly fit stock shocks,not the bigger aftermarket ones..

I also bought a pair of Superior leaf type helper springs,at the same yard sale--they are full length and look like a bow you'd go hunting with--they would require taking the u-bolts off and you'd need sufficent threads on them to accept the thickness of them,but they are skinnier than the stock GM tapered leaves are,I had doubts they would work well up front (they are designed more for rear applications),so they are still sitting on a shelf in my garage gathering dust...

I was tempted to try a pair of the clamp on overload coils I have used in the rear made by Superior up front,but you'd have to make some custom brackets to attach them to the axle and frame rail...coild add lift ,but wont make the ride as harsh as adding leafs would...

Dont try what a friend of mine did--he got a pair of air shocks and put them up front,they worked great--until one day one of the lines got pinched and let one of them lose the air suddenly,he almost had a crash when the truck tilted to one side--he had a IHC pickup and the front sagged so bad the plow scraped the ground even with it fully "raised" when you'd hit bumps!...:eek:..
 
I almost got him beat on the air shocks.

On my first F150, I had the big bumper and PTO winch like the pictures you see on my F250.
Not quite as big, but heavy.

Had a friend who owned a NAPA store, so we studied dimensions until we found a set of Monroes that would fit.
Also bought a set of Gabriel Hi-Jackers for the rear.
Monroe had an air pump setup that mounted under the hood so you could adjust the shocks as you drove.
I built a control panel with two gauges, one for front and one for rear, a switch valve to select which one I was controlling, and a raise and lower button.

It worked great. If I was trying to make time down a washboard road, I could tune the shocks for the best ride and control.
With a gauge for each set, I could constantly monitor what pressure I had in each one.
Plus, I could turn the selector valve to off, hook up a long coiled air line I kept in the tool box, and use the pump to air up a tire.

I thought I had the perfect setup.
One slight problem. It was a coil spring suspension with the radius arms going back to the frame.
Started getting a strange rattle as I hit bumps. Finally traced it to the arm bushings being worn out and the arms rattling on the mounts.

Bought new bushings, parked the truck on concrete, put a rolling jack under each arm, took off the nuts, hooked my winch cable around a block on a post and back to the front axle.

Slowly winched my axle forward enough to clear the mounts. Replaced the bushings and let the arms slide back in.

About a month later, the rattle was back.
Did it again with the plastic bushings. They cracked and fell out. Put the rubber ones back in.

One day I had the front tire off, and was sitting on a stool pulling my hub to check the wheel bearings for water.
Started looking at the suspension.
I suddenly realized that the coils were directly over the axle, but the shocks were about 6 to 10 inches back down the radius arm!
Which meant that a good portion of the weight the shocks were supporting were bearing down on the arm bushings putting a load on them they were not designed to handle.
They are only supposed to see a front to back load, not up and down.

I replaced the front springs with heavier ones, and lowered the pressure on the front shocks to almost zero.
Truck rode good, and every so often I would tweak the ride with the front shocks, but not for long.

Never had a shock collapse, but I went through a lot of bushings until I figured out my stupidity.
 
you could try a set of Timbrens too, just get the rubber springs and not the kit. should be less than 75$
 
I tried to get it home today to no avail. It is shifting through all gears now, but has little power. Except going downhill. It barely goes up hills. The last big hill it started cutting out and backfiring through the Q-jet and died. I couldn't get it started again after that. I don't know of it's the float or needle or filter or timing or....

Tomorrow I will change the filter and check the advance weights and I don't know what else. Any suggestions on what to look for? It idles well, but doesn't move well.

I just want to get it home. I tried driving once before and it did the same thing. But the last time I went out there I didn't have the problem again. It made it a lot farther this time though before it happened. Maybe by tuesday or wednesday it will make it to the driveway.
 
I finally got it home! Barely. I found a plug wire arcing on the exhaust manifold and changed it. that helped a lot. But the real reason it wouldn't go is.....
The front passenger brake caliper is seized up. I was almost home when I thought I smelled hot brakes. Then the death wobble came just blocks from my house. But I was able to ease it into the driveway. Then I saw the smoke from the front wheel.
At least it's in my driveway and not 50 miles from me. Now the work can begin. It's going to be a long road.

Thanks for all of your help and suggestions.
Chris.
 
glad to hear Chris!
Good luck, keep us updated with the repairs.
 
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