Help with a possible transmission issue

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FishingJake

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Hello,

I’m my son 16 was driving his truck to work today. Finally paid it off… and said it was “revving” high. Made it about a mile to work then said it would not move. I checked and fluid was very low . I added 3 quarts and checked the level and it’s good on fluid. However the truck will only go in reverse now. We’re complete amateur mechanics. Just looking for help and advice to get the kid back on the road he worked his butt off to get a square body. Thanks I’m advance. From the looks of things I found a good group to help us out.
 

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DoubleDingo

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If it was running three quarts low and revving the engine yielded slow speed, I'd have to lean towards a rebuild of the transmission. What transmission is in the truck? TH350, TH400, 700R4?

@NickTransmissions @Matt69olds @HotRodPC @Ricko1966

What are you thoughts on this one?
 
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DoubleDingo

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FishingJake said:
Thanks I will have to try to figure out what kind of transmission
Click to expand...
Look at the pan. Compare to this chart of pan shapes.

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FishingJake said:
Hello,

I’m my son 16 was driving his truck to work today. Finally paid it off… and said it was “revving” high. Made it about a mile to work then said it would not move. I checked and fluid was very low . I added 3 quarts and checked the level and it’s good on fluid. However the truck will only go in reverse now. We’re complete amateur mechanics. Just looking for help and advice to get the kid back on the road he worked his butt off to get a square body. Thanks I’m advance. From the looks of things I found a good group to help us out.
Click to expand...
Start the truck foot on brake go through all the gears and back to park. Engine idling and truck on level ground,check your transmission fluid it needs to be between the marks. If it's between the marks I'd say transmission rebuild. Not between the marks, add fluid and check again,see if it drives okay. What transmission? Th350 or Th400 pull the hose off at the vacuum modulator see if it full of fluid.
 
NickTransmissions

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FishingJake said:
Hello,

I’m my son 16 was driving his truck to work today. Finally paid it off… and said it was “revving” high. Made it about a mile to work then said it would not move. I checked and fluid was very low . I added 3 quarts and checked the level and it’s good on fluid. However the truck will only go in reverse now. We’re complete amateur mechanics. Just looking for help and advice to get the kid back on the road he worked his butt off to get a square body. Thanks I’m advance. From the looks of things I found a good group to help us out.
Click to expand...
Sound like forward clutch has burnt (or possible low roller one-way assembly failure), assuming you have the correct amount of fluid in the system. This is true regardless of what transmission is installed as they're all designed (and function) more or less the same way when it comes to the forward clutch.
 
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FishingJake

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Hi it’s this one . Now I’m under it I see it’s been leaking pretty good.
 
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FishingJake

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Ricko1966 said:
Start the truck foot on brake go through all the gears and back to park. Engine idling and truck on level ground,check your transmission fluid it needs to be between the marks. If it's between the marks I'd say transmission rebuild. Not between the marks, add fluid and check again,see if it drives okay. What transmission? Th350 or Th400 pull the hose off at the vacuum modulator see if it full of fluid.
Click to expand...
TH350
 
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FishingJake

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Ricko1966 said:
Start the truck foot on brake go through all the gears and back to park. Engine idling and truck on level ground,check your transmission fluid it needs to be between the marks. If it's between the marks I'd say transmission rebuild. Not between the marks, add fluid and check again,see if it drives okay. What transmission? Th350 or Th400 pull the hose off at the vacuum modulator see if it full of fluid.
Click to expand...
I did this fluid stayed in the marks. Still won’t go into D , D1 or D2. It’s a Th350.
 
Bextreme04

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FishingJake said:
TH350
Click to expand...
wow, I would not have expected that. 86' was the last year you could get a TH350 and it was only available as the TH350-C model with a lockup converter and even then only available as an option in the Vans and Trucks. I would have expected a 700R4, but they aren't easy to mistake for each other.

Like others have said, you likely burnt up the forward clutches by running it low on fluid. They are pretty easy to rebuild yourself and I wouldn't expect them to cost much to have a local shop rebuild for you if you don't have the time or feel comfortable doing it yourself. If you have a bunch of metal in the pan, you will likely need a fresh converter too.
 
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FishingJake said:
I did this fluid stayed in the marks. Still won’t go into D , D1 or D2. It’s a Th350.
Click to expand...
Yep you need a transmission.If you are mechanically inclined a Th350 isn't a tough one.
 
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Ricko1966 said:
Yep you need a transmission.If you are mechanically inclined a Th350 isn't a tough one.
Click to expand...
Man that stinks looks like he is going go mowing a bunch more lawns and bussing of tables. I imagine it’s not going to be cheap.
 
Matt69olds

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A TH350 is the perfect beginner transmission. It’s easy to build, doesn’t require much in special tools, and what special tools are needed is easy to fabricate.

Watch some YouTube videos before deciding if it’s something you want to attempt. Have a large clean work area, lots of bags to label parts, and take lots of pictures and notes.

The worst part about building 350 transmission is parts are getting scarce. There was a time you almost couldn’t give away Th350s, now people are paying a couple hundred bucks for good pumps. This might be a situation where a 700 swap might be cheaper.
 
Bextreme04

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FishingJake said:
Man that stinks looks like he is going go mowing a bunch more lawns and bussing of tables. I imagine it’s not going to be cheap.
Click to expand...
Its about $200 for a full rebuild kit, just make sure it is for a 350C not just a 350. You can probably also just roll the dice and see what can be found on facebook marketplace or in the local pick n' pull. If you drop the pan and the fluid is burnt and dark, but no metal shavings, you can probably just get away with a quick pull apart, clean, and rebuild.
 
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