700R4 issue

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fallguy

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On the highest, at 60-70 mph cruising, when I come to a point that I have to slow down,,,a machine gun vibration starts...can feel it in the whole truck and it's not a slight vibration either. So then if I shift it out of overdrive it runs fine, no slow down vibration.

Stopped at a red light, light turns green, truck won't move...just makes noise, let off gas and shift out of OD....able to move again.

Thoughts?

Also, Could this be why my truck has been so lethargic for over a year and can't seem to get out of its own way....much less anything else on the road???

GM 290hp 350, 4.10 axles, 1406 Edelbrock carb, 700R4 tranny.
 

HotRodPC

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Could be a # of not so good things. First thing without looking at a daignostic flow chart, I' be thinking Torque Converter.
 

89Suburban

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My lock up converter is starting to slip on mine so I unplugged it and the shuddering went away and it shifts/holds gears fine for now.
 

fallguy

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HotRodPC

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Yes Sir. If the fluid is Black and smelled burnt. It's all over with.

So you're getting the High Stall too. :waytogo: Basically high stall for stock. It's about 400 rpm higher than OEM. And it's possible the gutless issue could have been the trans. If you had a leak in the valve body somewhere holding a servo or band on when it was supposed to be off, that's like having brakes drag but actually even worse since it's dragging on the power train not the chassis. Could have been what burnt up the fluid too. So did you get to keep your core trans? Do Keep it if you can. Throw it out behind the shed on a block to keep it out of the water and cover it with something to keep water out of the pan so you'll have it for a rainy day to build if you need it.

Do keep us updated on your experience, and how it works out. :waytogo:
 

fallguy

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Update: tranny finally installed! My installer tells me bow tie overdrive used all new parts and made sure they were premium grade products (governor, shift kit, servo, etc). However, on test drive it wouldn't shift from 2-3. Bowtie authorized opening and investigation per warranty. 3 valves stuck. All had to be bore brushed out....frustrating. Won't have anything until next week after test drive.

My installer was extremely impressed with the TV cable setup. "Allot of thought and engineering went into that product. It's the best solution I have ever seen." My previous owner installed system went around the airline and was able to move slightly so basically it was part of the problem overtime too.

Final note. I get asked "hey who put that new engine in? ". I thought oh crap here we go again! Nothing but drama and constant issues related to stupidity after that installation! How man bolts hold on the bell housing??? Apparently 3....yes 3... Is the answer!!! And the 3rd was too small so it was held on by the hex corners....WTH!?! How did that thing not drop on the pavement when I was going 75mph?
 

HotRodPC

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Update: tranny finally installed! My installer tells me bow tie overdrive used all new parts and made sure they were premium grade products (governor, shift kit, servo, etc). However, on test drive it wouldn't shift from 2-3. Bowtie authorized opening and investigation per warranty. 3 valves stuck. All had to be bore brushed out....frustrating. Won't have anything until next week after test drive.

My installer was extremely impressed with the TV cable setup. "Allot of thought and engineering went into that product. It's the best solution I have ever seen." My previous owner installed system went around the airline and was able to move slightly so basically it was part of the problem overtime too.

Final note. I get asked "hey who put that new engine in? ". I thought oh crap here we go again! Nothing but drama and constant issues related to stupidity after that installation! How man bolts hold on the bell housing??? Apparently 3....yes 3... Is the answer!!! And the 3rd was too small so it was held on by the hex corners....WTH!?! How did that thing not drop on the pavement when I was going 75mph?

3 bolts? :eek: Your trans mount was in good shape obviously, and the crossmember bolted in tight. If you got rough enough with it, you could have done some damage. It also depends on which 3 bolts where in. With the alignment pegs and the 2 outside lower bolts good and tight, the bellhousing will stay put pretty good for light to mild driving habits. I've seen 4 work very well before in a Rat Rod that there was no way in hell they could get to the top 2 bolts.
 

fallguy

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Truck is done. Bore brush cleaned out the three valves. Wouldn't lockup and checked, previous owner disregarded wiring harness for older tranny so had to cut in new pigtail for electronic lockup? No clue about that whole deal. He says it goes down the road at about 1500rpm, but it's still lethargic as hell.

Told him that's an old problem and I've set vacuum advance, recurved distributor and next I'm going to lean it out to try to get some power back.

(.98primaries, Air horn gasket, Accelerator pump piston, Metering Rods: 71x47, #5 plain step up spring)

Maybe mess with timing too. Any thots on that?

He says that with a new 350 and 4.10s there's no reason it's so gutless. Good to know it's not just me!
 
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HotRodPC

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OK, I just posted in the other thread. So it's 4.10 gears and gutless? And even has a 3.06 first geared 700r4 and is gutless.? :shrug: And you're positive the transmission isn't dragging? Like trying to be in 2 gears at the same time. That's rare but it can happen if you have a servo getting fluid pressure from a misaligned valve in the valve body, or an inproper pin length to a band from a servo etc. If it's doing that, you should feel some type of braking or dragging. And then the only other thing I can think of, is your cam timing may be off. I'm not sure who installed the last timing chain or if it was recent or not.
 

87ChevyR10

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My lock up converter is starting to slip on mine so I unplugged it and the shuddering went away and it shifts/holds gears fine for now.

What symptoms does a slipping TQ converter show? Just curios. Thanks!
 

HotRodPC

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What symptoms does a slipping TQ converter show? Just curios. Thanks!

Exactly what he's talking about. Shuddering or vibration when it's trying to lock up, or shuddering shortly after it has locked up. The Torque converter clutch has gone bad is all. You can still use the trans just fine by disabling the TCC like he did. Just won't have lock up now and that will tend to allow the trans to run a bit hotter, and on a well used tired trans, the extra could possibly shorten the life left of the trans. But, if it's high mileage, it prolly wouldn't hurt just to drive it til the trans goes and replace the trans and converter at the same time.
 

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Exactly what he's talking about. Shuddering or vibration when it's trying to lock up, or shuddering shortly after it has locked up. The Torque converter clutch has gone bad is all. You can still use the trans just fine by disabling the TCC like he did. Just won't have lock up now and that will tend to allow the trans to run a bit hotter, and on a well used tired trans, the extra could possibly shorten the life left of the trans. But, if it's high mileage, it prolly wouldn't hurt just to drive it til the trans goes and replace the trans and converter at the same time.

Ok. I don't have that issue then. My trans performs just fine most of the time. I need a new TV able soon. If I give less than 1/4 pedal, it will stack up momentarily from 2 to 3 back to 2. As long as I have more than 1/4 pedal, it shifts fine. I did adjust the cable a few months back and noticed it has a bit of slack with the throttle closed. So, I don't know if taking out the slack will improve anything or not.

Lately, I've noticed it kicks into reverse pretty hard. It wasn't as bad during the frigid temps but seems worse in warmer temps; but they may be from not letting the truck idle down first. Shifting from P to OD is smooth. No hard shifting. And the shifting from gear to gear is smooth depending how much throttle I have applied.

Anyhoot, I think I'm good for now.
 

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I'd get a cheap pressure gauge and hook it up. That's how the pros do it. Just a simple pressure verification. Not trying to step on anyone's toes...

Sent from the dust in front of you!
 

fallguy

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First major 500 mile road trip. Here's what I found.

In overdrive it lacks power simply traveling down anything more than a flat road with no wind. Had to shift it out of overdrive to get anywhere above 65mph and stay there.

In overdrive, it down shifted constantly at 2000 rpms which brought it up to 2500rpm, then shift back to 2000 then down shift to 2500 etc.

If pulling the pontoon on any slight incline I had to manually shift to D2 (about 4-4500rpm) to stay above 50mph. Simply staying out of overdrive was lacking in any power on inclines or mild grade hills....aka would not stay up to speed, but also caused temp to raise more than I'd like.

Also I swear to god there's another gear in OD that I'm not hitting and seemed like I did once but I don't really know!

WTH with this thing!?!
 

HotRodPC

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First major 500 mile road trip. Here's what I found.

In overdrive it lacks power simply traveling down anything more than a flat road with no wind. Had to shift it out of overdrive to get anywhere above 65mph and stay there.

In overdrive, it down shifted constantly at 2000 rpms which brought it up to 2500rpm, then shift back to 2000 then down shift to 2500 etc.

If pulling the pontoon on any slight incline I had to manually shift to D2 (about 4-4500rpm) to stay above 50mph. Simply staying out of overdrive was lacking in any power on inclines or mild grade hills....aka would not stay up to speed, but also caused temp to raise more than I'd like.

Also I swear to god there's another gear in OD that I'm not hitting and seemed like I did once but I don't really know!

WTH with this thing!?!

What rear gear ratio do you have? What size tires? Sounding like you have 2.73 or 3.08 rear gears and possibly some 33x12.50 or 35x12.50 tires.
 

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