Author Topic: TH350 Problems  (Read 6321 times)

Offline uprising

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Re: TH350 Problems
« Reply #45 on: January 07, 2020, 10:04:37 PM »
I hoped it is only the seal... :-X
I will clean the transmission and try to make more pictures from the whole transmission.
So the tube is also maybe damaged? If i understand correct, Ron350 mentioned that there must be crimped bead which is a limiter for not getting to far into pan? Is it neccessary or is the o-ring tight enough to keep the dipstick in place? How far is the tube inside the pan? Can you give me the sizes off the two o-rings? I don‘t want to make an order at rockauto for two rings ;)
The costa for shipping are a lot more like the two peaces...
Detent cable is the one from Shift indicator right? Translation is a little bit tricky.
I checked the area between wngine and transmission and it is looking dry. This was my biggest fear

Offline ron350

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Re: TH350 Problems
« Reply #46 on: January 07, 2020, 11:23:36 PM »
It looks like you need a new dipstick tube or something.
What year and model truck do you have?


« Last Edit: January 08, 2020, 12:09:10 AM by ron350 »
1975 C10 step side stock with 350 two bbl. & 350 trans.

Offline uprising

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Re: TH350 Problems
« Reply #47 on: January 08, 2020, 12:13:46 AM »
dang it.. i know it ;)
It is a K10 from 73 or 75. Can‘t say it exactly because there is a wrong VIN on the car. Seems that they changed the cab.

Offline Irish_Alley

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Re: TH350 Problems
« Reply #48 on: January 08, 2020, 12:21:36 AM »
you can buy a top hat seal it will replace the o-ring
https://www.jegs.com/i/ACDelco/065/1259475/10002/-1

looks like most of the leak is all coming from the dipstick side.

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Offline bd

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Re: TH350 Problems
« Reply #49 on: January 08, 2020, 12:48:12 AM »
The dipstick tube is positioned and held in place by a welded mounting bracket that is retained by one of the upper bell housing bolts.  The bracket could be bent or broken loose from the tube, allowing the tube to sit too low.  As long as the bracket is still there either scenario is correctable without replacing the tube by rebending or brazing.  The tube is inserted far enough into the case that the rolled bead may be seated into the chamfer just below the surface. 

The plastic detent cable is located about 75 mm forward of the dipstick tube and is retained by a small (1/4" or 6 mm) bolt.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline uprising

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Re: TH350 Problems
« Reply #50 on: January 08, 2020, 02:18:47 AM »
Thanks for the hint irish_alley! I try to get the part in germany. Maybe someone have...;)
@bd thanks again! Also for the conversion to metric ;) I think the best way is to change the whole tube. In the meantime i also found a seal made of gum. Only if i have to remove the pan again:)

Offline Irish_Alley

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Re: TH350 Problems
« Reply #51 on: January 08, 2020, 11:53:13 AM »
also if the bracket is bent it can create a pinhole and trand fluid could be out of that. kind of hard to see on you pics but you should be able to find the trail coming from the mounting bracket
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

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Offline ron350

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Re: TH350 Problems
« Reply #52 on: January 08, 2020, 12:09:13 PM »
It will be interesting to see what that dipstick tube looks like when it is removed.

The 1975 dipstick o-ring size is a -113 or 13.94mm ID x 2.62mm cross section or 9/16 ID x ¾ OD x 3/32 cross section.
1975 C10 step side stock with 350 two bbl. & 350 trans.

Offline uprising

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Re: TH350 Problems
« Reply #53 on: January 08, 2020, 12:47:46 PM »
Hey Masters :)
Today i try to clean the trans a little bit but The durt must be 30years old! It is impossible to clean it nicely while it is mounted in the truck. I pulled a little bit at the tube and the welded bracket is visible. I ordered a new pipe, and the mentioned plug from irish_alley! Also i remove the detent cable and i will renew the o-ring. Should be a normal size which can be bought in germany.

Just another question: i checked the engine ID to get the info which detent cable is used (different seals) I got the iD from the passanger side on the front of the engine (behind alternator).
It says the engine is from 75 and it is a 400cui?! If this is the correct interpretation i would expact not the o-ring seal at the detent cable! The id is T1126TLS. Maybe i checked wrong.
« Last Edit: January 08, 2020, 12:58:59 PM by uprising »

Offline Shifty

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Re: TH350 Problems
« Reply #54 on: January 08, 2020, 01:05:30 PM »
Thanks for the hint irish_alley! I try to get the part in germany. Maybe someone have...;)
@bd thanks again! Also for the conversion to metric ;) I think the best way is to change the whole tube. In the meantime i also found a seal made of gum. Only if i have to remove the pan again:)
If it helps, Dorman/Motormite offer one, and they are a world-wide company, part number is 65113. 
87 V20 Standard Cab Longbed (current)

87 R30 3+3 Longbed (days of yore)

Offline JohnnyPopper

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Re: TH350 Problems
« Reply #55 on: January 08, 2020, 08:22:49 PM »
It looks like your mounting bracket was moved/bent/damaged and it lifted your tube out just enough to leak.

Take our your dipstick and use a block of wood and a hammer to gently knock it down into the right position.

The ring should be just rest just at the top of the case, if not a tad lower.

Might fix your leak and save you getting a new tube. 
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction

Offline uprising

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Re: TH350 Problems
« Reply #56 on: January 09, 2020, 12:36:05 AM »
@JohnnyPopper:
No, pulled it a little bit to see if the welded ring is still there. In one of the other pics you can see that the tube was to far in the transmission. The o-ring is also at the end of the tube. I ordered a new tube and also the mentioned alternative seal for the tube. Should arrive tomorrow :)
To change the o-ring from the detent cable: can i just pull it out or is the internal wire somewhere connected in the transmission?! Yesterday i release the screw and pulled it a littlw bit to see which seal i need and felt that it can be pulled out completely.

Offline ron350

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Re: TH350 Problems
« Reply #57 on: January 09, 2020, 08:20:59 AM »
Uprising I don’t think a boot seal will fit on that dipstick but we will find out.

You might want to buy a seal kit that will have all the seal or o-ring that you need to seal all of your leaks.

https://www.ebay.de/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=turbo+350+seal+kit&_sacat=0
« Last Edit: January 09, 2020, 11:33:16 AM by ron350 »
1975 C10 step side stock with 350 two bbl. & 350 trans.

Offline bd

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Re: TH350 Problems
« Reply #58 on: January 09, 2020, 09:36:10 AM »
To change the o-ring from the detent cable: can I just pull it out or is the internal wire somewhere connected in the transmission?! Yesterday i release the screw and pulled it a little bit to see which seal I need and felt that it can be pulled out completely.

Disconnect the detent cable from the carburetor to provide slack in the cable for the next steps.  Unbolt the cable from the transmission.  As you slowly pull the cable out of the transmission you will find its end hooked to a steel link.  Support the steel link with one hand as you carefully unhook the cable.  After the new seal has been installed on the cable, smear the seal with clean ATF.  Support the steel link and rehook the cable end.  Carefully slide the cable back into the transmission over the link and install the bolt.  Verify that the cable is properly attached to its steel link inside the transmission by pulling the disconnected cable end at the carburetor.  You should feel some resistance as you pull against light spring tension.  Reconnect the detent cable to the carburetor.  Start the engine, check the fluid level and road test.  Verify that the transmission downshifts correctly into passing gear.  Inspect and make sure there are no leaks.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline uprising

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Re: TH350 Problems
« Reply #59 on: January 09, 2020, 11:18:13 PM »
Awesome! Thanks for your detailed help. The part will arrive today and i will try to get the missing o-ring for the detent cable. If not, i will maybe order the set mentioned by Ron. Hopefully i will find some time on Sunday. Keep you updated