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-   -   TH350 input shaft tabs (http://67-72chevytrucks.com/vboard/showthread.php?t=760719)

Nima 04-01-2018 10:08 AM

TH350 input shaft tabs
 
Hi:
The tabs on my TH350 input shaft which the torque converter suppose to slide over them ( I am sorry I don't know if these parts have specific names) have broken. I was trying to connect the transmission to the engine but the bell housing wouldn't seat right next to the block. When I looked inside I noticed the converter is not sliding all the way back and that was when I noticed these two small pieces are broken in front of the input shaft seal and they don't let the converter slide all the way in.The transmission is fairly recent rebuilt. Are these tabs critical for the function of the transmission or they are just guides? Do I have to replace the input shaft? Are they even on the input shaft? I don't know much about the structure of the transmission.
Thanks

B. W. 04-01-2018 11:39 AM

Re: TH350 input shaft tabs
 
If they are what I think they are - they are used to "attach" the converter to the trans. The converter drives (or turns) the trans using these tabs. If the converter doesn't fit into those tabs then the trans will not turn.

Will need to replace the shaft.

Post pics if you can.

WRONG, WRONG, WRONG see other posts!

Nima 04-01-2018 11:45 AM

Re: TH350 input shaft tabs
 
Thank you for the reply.
I thought the converter engages the transmission through different sizes of the spines on input shaft. Again, I have never worked on automatic transmission before therefore my knowledge is very limitted.

YoungPup1977 04-01-2018 12:20 PM

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Maybe you broke the pump gear tabs off if you donít know how the TC fits into the transmission when bolting it up to the engine
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YoungPup1977 04-01-2018 12:26 PM

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Here is a pic with the TC hub in the pump gears Hope this helps you to understand how the pump tabs engages into the TC. You are not the first one to break the pump gears. Good Luck !!!!

The pump will need to be pulled out of the case, remove the 5 bolts holding the stator to the pump body. Replace the gears (measure the height of the gears you have).....the pump body and stator will need to be aligned when tightening the 5 bolts previously removed. Easy stuff.
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Ironangel 04-01-2018 01:13 PM

Re: TH350 input shaft tabs
 
A mistake easily made is installing that pump gear upside down. If a shop installed the gear it's on them, if you did it consider it paid education...You'll have to pull the pump, measure the thickness of the gears and replace them as a set. No big deal actually, the key is knowing when the converter is fully engaged. The Turbo-350 should have 1-1/8" inches of clearance from bell housing to converter pads. If you have to use the bolts to suck a bell housing to the block,STOP! Sometimes a converter will disengage while raising and installing the trans. http://converter.com/images/CONVERTER%20INSTALL.pdf

Nima 04-01-2018 01:28 PM

Re: TH350 input shaft tabs
 
Those tabs look like the two pieces that I have found. I have installed torque converters and transmission few times but I don't know much about their internal parts. I just knew that the converter has to be seated completely when bolted to flywheel. Do I need a y special tool for this job? Is the input shaft attached to the pump and it will just pupils out when I remove the casing bolts?

YoungPup1977 04-01-2018 05:40 PM

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Once you remove the outer pump bolts you will notice two holes that are threaded in the pump body housing. Use a slide hammer tool to pull pump out of the case by threading the tool into these holes. Be careful of the direct drum and the input (forward) drum (clutches ) from moving forward when pump is removed. When you reinstall the pump you want to ensure both drums are seated down all the way into each clutch pack. Check out the pic below. Itís a cheap alignment tool for the stator and pump body to be aligned before assembly back into the case.
[size=1]Posted via Mobile Device[/size

Three hose clamps. Again. Cheap and easy like everyone wants it 😀

B. W. 04-01-2018 09:35 PM

Re: TH350 input shaft tabs
 
Hey guys, I was way off! My excuse- too early, not enough coffee, in a rush to get to church... pick one!

As stated by others, those tabs drive the pump, guess I'm getting dumber with age?

YoungPup1977 04-01-2018 10:17 PM

Quote:

Originally Posted by Ironangel (Post 8227373)
A mistake easily made is installing that pump gear upside down. If a shop installed the gear it's on them, if you did it consider it paid education...You'll have to pull the pump, measure the thickness of the gears and replace them as a set. No big deal actually, the key is knowing when the converter is fully engaged. The Turbo-350 should have 1-1/8" inches of clearance from bell housing to converter pads. If you have to use the bolts to suck a bell housing to the block,STOP! Sometimes a converter will disengage while raising and installing the trans. http://converter.com/images/CONVERTER%20INSTALL.pdf

A tip to note here is once you put your bolts in to the engine thru the bell housin make sure the TC turns freely. If the TC doesnít turn most likely the TC is not engaged into the pump gears correctly.
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Ironangel 04-02-2018 09:38 AM

Re: TH350 input shaft tabs
 
If you dont install the small drive gear correctly the converter will not engage properly. Some gears have a mark like the one shown in Young Pup's pic, some dont. What his photo angle dont show is the bevel on one side of the drive tangs, thats what your looking to orient away from the seal, toward the rear of the vehicle. Nima, you really should get a manual because there are a few details that must be followed so your not doing this a third time. That pump seal can be stubborn and if it gets nicked it must be replaced. Petroleum Jelly smeared on the seal, and the sealing surfaces help, and if you have an empty 2 liter pop bottle around, cut some "feeding tools" (poker card size) to feed and guide the seal past that first critical edge. Use the thin plastic like a shoe horn, that thin plastic protects the seal past that edge. Ron Sessions published this manual, money well spent. https://www.themotorbookstore.com/tu...iABEgK42PD_BwE The threaded holes for using slide hammers to remove the pump are located at 11 o'clock and 5 o'clock there abouts with the pan flat on the bench. Be careful with the sealing washers, they should be replaced but if you dont damage the existing washers clean them and smear a thin coat of silicon on the black side, black side on the pump. Be very careful torqueing those bolts, the case is usually toast if those bolts strip or crack the bosses...All for now.

Nima 04-04-2018 06:29 PM

Re: TH350 input shaft tabs
 
Well, thank you all for the ingormation. I have to say that I am a little intimidated to tackle this job. I guess I can call local tranny shop to see how much they charge first.

YoungPup1977 04-04-2018 10:13 PM

Re: TH350 input shaft tabs
 
Sounds like a great plan, turn key job for the trans shop...plus its already a "fairly recent rebuild"...... Have Fun !!!!

Nima 04-10-2018 12:12 AM

Re: TH350 input shaft tabs
 
So, The shop is quoting me $250-350 to fix it depend upon if only the gear need to be replaced or if they have to swap the whole gear pump! They say if I forced the torque converter to break the tabs, could have damaged other component as well. This sounds steep to me
So, my question is if the whole pump assembly needs to be replaced, is it like removing this one and put the other one back in, or there is more into it? I see the gear pump repair kit (including all the seals and gaskets) are $33 at transdepot, and rebuilt gear pumps are $150 on ebay? Any opinion?
Thanks

YoungPup1977 04-10-2018 07:03 AM

Re: TH350 input shaft tabs
 
Quote:

Originally Posted by Nima (Post 8234680)
So, The shop is quoting me $250-350 to fix it depend upon if only the gear need to be replaced or if they have to swap the whole gear pump! They say if I forced the torque converter to break the tabs, could have damaged other component as well. This sounds steep to me
So, my question is if the whole pump assembly needs to be replaced, is it like removing this one and put the other one back in, or there is more into it? I see the gear pump repair kit (including all the seals and gaskets) are $33 at transdepot, and rebuilt gear pumps are $150 on ebay? Any opinion?
Thanks

Always get another estimate, seems a bit steep to me too. The pump stator and pump body could of been damaged from the pump gears being damaged. Replacing the entire pump you need to make sure the end play in the trans is correct...the stators are different, some require a torrington bearing and some take a thrust washer. We are here to help.....

Nima 04-10-2018 08:46 AM

Re: TH350 input shaft tabs
 
Thank you Youngpup.
Are these two gear pumps, bearing versus thrust washer, interchangeable? I see online some companies are marketing their gear pumps as "universal".

YoungPup1977 04-10-2018 09:08 AM

Re: TH350 input shaft tabs
 
Quote:

Originally Posted by Nima (Post 8234789)
Thank you Youngpup.
Are these two gear pumps, bearing versus thrust washer, interchangeable? I see online some companies are marketing their gear pumps as "universal".

Yes they are.
End play is important in this transmission so if you were to do it yourself I just wanted you to know end play must be checked.

You may not have to buy the entire pump/stator assembly, you may get by with only buying the pump gears. Only way to know for sure is to pull the pump out of the case...its important to buy the correct pump gears...aftermarket company's buy old bad pump's and cut them down and use thicker pump gears, this is why you must know the thickness of your gears....


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