Help with rebuilt 1986 TH350C

[drummingrocks]

The linkage isn't adjusted right you probably need to put in neutral to actually be in drive as far off as you are saying reverse is. Almost 1 position off. Disconnect the linkage put thr transmission in neutral manually,count the detents. Put the shift lever in the truck in neutral. Adjust the linkage until it can be attached without loosing the transmission or shifter positions.

I thought that might be the case too, but wouldn't that make it never go all the way down into 1? I can pull it all the way down into 1 with no problem. It's the factory linkage, nothing aftermarket. Reverse is the only gear that feels weird like this. If I'm driving and move the shifter from 2 up to drive, when I try to go further I'm into neutral and it still never goes into 3rd.

 

[Ricko1966]

I thought that might be the case too, but wouldn't that make it never go all the way down into 1? I can pull it all the way down into 1 with no problem. It's the factory linkage, nothing aftermarket. Reverse is the only gear that feels weird like this. If I'm driving and move the shifter from 2 up to drive, when I try to go further I'm into neutral and it still never goes into 3rd.

Well you know it's not adjusted right now,so adjust it see if your problems go away.

 

[drummingrocks]

Well you know it's not adjusted right now,so adjust it see if your problems go away.

I don't know what to adjust, unless the factory linkage is threaded? The end on the transmission isn't. And this is the same linkage the truck used when it shifted to 3rd, before I rebuilt the transmission.

 

[Ricko1966]

Look at this linkage,see the bolt head. That's a pinch bolt that holds the rod in position.

 

[drummingrocks]

Look at this linkage,see the bolt head. That's a pinch bolt that holds the rod in position.

Got it, thank you for the pictures. I'll give it a try.

 

[NickTransmissions]

@NickTransmissions

I got the the valve body removed today. Here's what I found:

1. The roll pin and retainer for the manual low control valve had come loose, and the spring was hanging slightly out of the bore. I found both the pin and the retainer in the transmission pan (parts 21 and 22 in the TH350C ATSG book on the valve body exploded diagram). When I found this, I was hoping this was a smoking gun for why it wouldn't shift to 3rd.

2. When I got the valve body on the bench, it had some small rust particles visible. This was a used valve body I got on eBay after the original was unusable, and I knew it was rusty when I got it, but I thought I cleaned it extremely well. I guess I missed something.

Despite the bit of dirt in the valve body, all valves still moved freely, including the 2-3 shift valve. Since I didn't like the rust in the valve body and I had since bought another, much nicer TH350C valve body used on eBay, I decided to go back together with that one.

The valve body I installed today was spotless when I got it. I went ahead and disassembled everything just to make sure it was clean and moved freely. I also installed the shift kit springs (TransGo SK-350) into this new valve body.

I went for a drive, and it still won't shift into 3rd.

One thing I noticed, and I'm just grasping at straws now: Reverse doesn't feel right. If I don't physically hold the shift lever up almost to the park position, the truck will go into reverse but seems like it slips. If I hold the shift lever as close to park as I can get it, the truck goes into reverse firmly and doesn't slip at all when moving backwards. It did this with the old valve body I took out as well as the new one I installed today.

Also, when I got the truck all of the lockup stuff was still hooked up. It still is. I'm not sure if that could somehow keep it from shifting, but I'm 99% sure the truck did shift to 3rd before I rebuilt the transmission, and all of the lockup stuff was plugged in back then too.

Also also, and this may completely be my imagination: I've run the truck up to 55-65mph in 2nd, and it seems like I hear a slight whine from somewhere, almost like how a power steering pump sounds when it's low on fluid. I'm not sure it's coming from the transmission, but wanted to mention it in case it helped with the diagnosis.

Thank you again for your help.

I think your direct clutch pack is going out - transmission likely needs to come out for overhaul. Sounds like you did everything correctly with the valve body...The roll pin coming loose, part way out may have impacted your manual low function but wouldn't have had a bearing on your ability to grab 3rd gear.

 

[drummingrocks]

I think your direct clutch pack is going out - transmission likely needs to come out for overhaul. Sounds like you did everything correctly with the valve body...The roll pin coming loose, part way out may have impacted your manual low function but wouldn't have had a bearing on your ability to grab 3rd gear.

That's a bummer. Everything in the trans is new and was replaced when I did the rebuild. My clearance on the direct clutch pack was right in the middle of the spec, and the clutch pack also applied properly when I did an air check. Will it hurt to drive it like this until I can get it back apart? Any chance I missed or left out a seal in the direct clutch pack, even though it passed an air check?

 

[NickTransmissions]

That's a bummer. Everything in the trans is new and was replaced when I did the rebuild. My clearance on the direct clutch pack was right in the middle of the spec, and the clutch pack also applied properly when I did an air check. Will it hurt to drive it like this until I can get it back apart? Any chance I missed or left out a seal in the direct clutch pack, even though it passed an air check?

I have no idea if you left out a seal or what you may have done or not done but I'd drop the pan, valve body, spacer plate and gaskets then do a case air check to see if the direct clutch is applying. If you burnt it up, you'll know it when you drop the pan and see the fluid and bottom. If the fluid looks clean (no burnt smell) and clutch applies like it should then your problem is elsewhere (prob valve body).

Can't really get you any closer than that over the net - you have to get your hands dirty...

 

[drummingrocks]

I have no idea if you left out a seal or what you may have done or not done but I'd drop the pan, valve body, spacer plate and gaskets then do a case air check to see if the direct clutch is applying. If you burnt it up, you'll know it when you drop the pan and see the fluid and bottom. If the fluid looks clean (no burnt smell) and clutch applies like it should then your problem is elsewhere (prob valve body).

Can't really get you any closer than that over the net - you have to get your hands dirty...

I tried a new Sonnax governor, hoping that might be the problem. Still no 3rd.

I pulled the transmission out yesterday. The fluid is still bright red, and the pan itself is clean. There were no broken rings on the pump. The intermediate frictions and steels still looked new. I pulled the forward and direct clutches apart and both sets of frictions and steels still look new as well. I checked the lip seals for forward and direct, and all are there and not torn or cut. The direct clutch still has the 3rd lip seal and is not dual fed. Both the forward and direct drum still have their check balls in place.

The valvebody looked clean and I verified that the gaskets hadn't shifted or moved. I also verified that all 5 check balls were in place. I also verified that the modulator valve was moving smoothly in its bore.

Update: I might have found something. Not sure if this points to anything. When I assembled the transmission, it was missing the check ball in the forward drum. I put a check ball, same size as what you would put in the valve body, in the forward drum when I assembled it. It appears this ball is too large, especially when I compare it to the factory one in the direct drum. It looks like this could be blocking fluid flow.

Pictures attached of the forward drum (with the ball bearing I put in during the rebuild), and the direct drum (with factory check ball still in place).