Spookee
Junior Member
- Joined
- Nov 4, 2023
- Posts
- 22
- Reaction score
- 37
- Location
- oregon
- First Name
- hannah and pat
- Truck Year
- 1984
- Truck Model
- k10
- Engine Size
- 350
Hi! We recently bought a 1984 chevy k10 with a 700R4 transmission. it sat for about 14 months before we bought it, so we are chipping away at getting work done on it. It has been our daily driver truck but now is having a shifting problem that we can't figure out! This forum has a lot of great information so I'm hoping someone has an idea or can point us in the right direction.
Last month we had the intake gaskets replaced and a transmission service to change the fluid. Thing were working OK (truck still needed work) but it was shifting fine as best we could tell. The throttle had what felt like a hitch in it, you'd press it and it would get hung up, so you'd press it harder and the truck would sort of jump like something got unstuck. So we replaced the throttle cable and kick down cable and it seemed to be driving better, except we noticed that at first the truck was having a hard time getting into overdrive when going up a hill - we have heard that this can be common for 700R4 transmissions?
Throughout the process there were some points where the throttle would get hard and you couldn't press it down unless you put the truck into park to reset it and get the pressure off. So we were told to get the valve related to internal pressure in the transmission (sorry idk what this is called) replaced. At this time we also noticed that the overdrive shifting issue was becoming more of an issue. It was taking the truck a long time to get to 3rd - 4th and pick up speed in a way that was different from when we first got it.
We got the valve replaced and right away noticed that it wasn't shifting as smoothly, you felt it more and it was clunkier but the cable wasn't getting locked up. But the overdrive issue persisted especially when going up steep hills when not already at a high speed. When the trans shop replaced the valve they didn't have to drop the whole transmission. He also said that he didn't see any metal shavings or anything that would indicate a more serious problem.
Also, I don't remember exactly when it was done but we had the carb adjusted because it was having a hard time starting in the morning, so it was adjusted to a high idle that we had to kick down by punching the throttle before we drove. I wonder if this is related to the issue now.
We called the trans guy back and he didn't think our issue was anything major - he said we should just try driving it around in 3rd gear manual and see how it was. So we started to drive in 3rd gear manual and noticed a few times when accelerating uphill that it was now having a hard time getting from 2nd to 3rd. We would accelerate and feel the truck try to shift and the RPMs would increase, the engine would rev and try to kick up to 3rd but it would go back down to 2nd and then we'd eventually have to let off the gas and slowly ease back in and accelerate at a really slow rate. Eventually it would get itself from 2nd to 3rd
However...last night after filling up the tank with gas (premium), the truck drove the smoothest it has in a long time, shifted smoothly and even got up to overdrive until we had to come to a stop to make a left turn, deaccelerating from 55 to 0. Then after making the turn the truck could not get back into 3rd, it wouldn't shift beyond 2nd. Tried to drop it into park a couple times, turn off and restart but nothing mattered. Ended up having to drive home very slowly in manual 2nd. We also checked the trans fluid and it is clear/red without any metal bits or gunk that we can see.
We were told by the trans people to rule out the kick down cable or the throttle cable so we fiddled with them last night with no difference, still couldn't get out of 2nd gear. At this point we are unsure what to do, 2 transmission shops didn't think that it was anything major in the transmission but we have no idea. Could it be because of the high idle adjustment? or related to the carb since our Edelbrock is older. Not sure where to start since we are not well versed in older vehicles. Any help would be really appreciated!
Last month we had the intake gaskets replaced and a transmission service to change the fluid. Thing were working OK (truck still needed work) but it was shifting fine as best we could tell. The throttle had what felt like a hitch in it, you'd press it and it would get hung up, so you'd press it harder and the truck would sort of jump like something got unstuck. So we replaced the throttle cable and kick down cable and it seemed to be driving better, except we noticed that at first the truck was having a hard time getting into overdrive when going up a hill - we have heard that this can be common for 700R4 transmissions?
Throughout the process there were some points where the throttle would get hard and you couldn't press it down unless you put the truck into park to reset it and get the pressure off. So we were told to get the valve related to internal pressure in the transmission (sorry idk what this is called) replaced. At this time we also noticed that the overdrive shifting issue was becoming more of an issue. It was taking the truck a long time to get to 3rd - 4th and pick up speed in a way that was different from when we first got it.
We got the valve replaced and right away noticed that it wasn't shifting as smoothly, you felt it more and it was clunkier but the cable wasn't getting locked up. But the overdrive issue persisted especially when going up steep hills when not already at a high speed. When the trans shop replaced the valve they didn't have to drop the whole transmission. He also said that he didn't see any metal shavings or anything that would indicate a more serious problem.
Also, I don't remember exactly when it was done but we had the carb adjusted because it was having a hard time starting in the morning, so it was adjusted to a high idle that we had to kick down by punching the throttle before we drove. I wonder if this is related to the issue now.
We called the trans guy back and he didn't think our issue was anything major - he said we should just try driving it around in 3rd gear manual and see how it was. So we started to drive in 3rd gear manual and noticed a few times when accelerating uphill that it was now having a hard time getting from 2nd to 3rd. We would accelerate and feel the truck try to shift and the RPMs would increase, the engine would rev and try to kick up to 3rd but it would go back down to 2nd and then we'd eventually have to let off the gas and slowly ease back in and accelerate at a really slow rate. Eventually it would get itself from 2nd to 3rd
However...last night after filling up the tank with gas (premium), the truck drove the smoothest it has in a long time, shifted smoothly and even got up to overdrive until we had to come to a stop to make a left turn, deaccelerating from 55 to 0. Then after making the turn the truck could not get back into 3rd, it wouldn't shift beyond 2nd. Tried to drop it into park a couple times, turn off and restart but nothing mattered. Ended up having to drive home very slowly in manual 2nd. We also checked the trans fluid and it is clear/red without any metal bits or gunk that we can see.
We were told by the trans people to rule out the kick down cable or the throttle cable so we fiddled with them last night with no difference, still couldn't get out of 2nd gear. At this point we are unsure what to do, 2 transmission shops didn't think that it was anything major in the transmission but we have no idea. Could it be because of the high idle adjustment? or related to the carb since our Edelbrock is older. Not sure where to start since we are not well versed in older vehicles. Any help would be really appreciated!
