RedZR

Can anyone walk me through the removal process for the gear selector shaft on a TH 350? After the pan is removed and the linkage is disconnected from the selector shaft, how do you disconnect the shaft to slide it out?

Thanks,
Dan

7T1vette

Why do you want to remove it? Is the seal leaking? If so, you can change the seal without removing the shaft.

TimAT

with 7T1-

If you have another reason to remove it, once you get the pan down, there's a nut that holds the rooster comb on and a nail that holds it in the case.

RedZR

Yes, the seal is leaking a little and it appears that someone attempted to remove the old seal and buggered it up so badly that the GM tool will not work. It looks as if they tried to split it or something but the flat edge of the seal (that faces outward) is no longer flat and I have no idea how to get the seal out without impacting the shaft.

I was going to remove (and inspect) the shaft and get the old one out that way- unless someone else has a better way, but that GM tool will not work on it now.

...Roger...

If the shaft is good you can put one in on top of the old one.
If memory serves me the shaft can't slide out without hitting the body so you have to drop tranny or drop valve body.

RedZR

I think someone may have already done that. First, the old seal was alomost to the edge of the trans case- no room to add another seal. Next, while the seal is buggered up, its not leaking that bad, thus I think there is another seal behind the buggered one that is catching some of it.

arrrgggggg.....its the little stuff

...Roger...

The shaft is pretty soft and can be damaged so even a new seal won't work. Fingers are crossed for you.

7T1vette

The 'standard' way of removing that seal is to pop it out by leveraging an icepick. Stick the point of a strong icepick tool into the lip of the seal and then lay the pick down so it lays [somewhat horizontal] on the outside edge of the bore with the point through the seal and under the seal casing. Now, pop the handle of the icepick with the palm of one hand while holding it in place with the other one. The casing should pop right out.

P.S. You want to limit contact of the pick with the surface of the shaft and not scratch the seal bore if you can help it. You can buy individual seals at NAPA. They should come with what looks like paint on the O.D.; that is a sealant for the bore. If it comes as plain steel O.D., you can use some non-hardening sealant on it before you press it in. If you don't have the correct tool to drive it in straight, use the backend of a deepwell socket that is a bit smaller than the diameter of the seal and with a square drive size that will fit over the shaft (3/8" drive I think). You may want to put tape over the shaft to keep the socket from contacting it while you install the seal.

RedZR

I have been looking at this thing for some time this evening and there is no way its coming out with the shaft in there. I read Roger's post with great interest (and some depression)- can someone confirm for me that the shaft will come out without moving the trans?

Thanks everyone,
Dan

RedZR

P.S. You want to limit contact of the pick with the surface of the shaft and not scratch the seal bore if you can help it. You can buy individual seals at NAPA. They should come with what looks like paint on the O.D.; that is a sealant for the bore. If it comes as plain steel O.D., you can use some non-hardening sealant on it before you press it in. If you don't have the correct tool to drive it in straight, use the backend of a deepwell socket that is a bit smaller than the diameter of the seal and with a square drive size that will fit over the shaft (3/8" drive I think). You may want to put tape over the shaft to keep the socket from contacting it while you install the seal. [/QUOTE]

Would you have the NAPA part number handy? Also, where is the best place to buy the shaft from?

Thanks!

7T1vette

NAPA has all the part numbers. Just tell them you want a shift selector shaft [outer] seal and they will order it. Why do you need a shaft? Did it get 'buggered-up'? If it is still in the tranny, I would suggest that you just buy two seals and install one to full depth and the other on top of it. That redundancy will provide you enough sealing power to overcome leakage due to scarring of the shaft. If it doesn't seal it up, what have you lost?....a few bucks for two seals and a little time. But if it seals OK, you've saved yourself a tranny teardown.

RedZR

In the event that the shaft is screwed up I was looking for a place to purchase one. I am worried that if I drive the new seal on top of the old one I may damage the shaft even more, but am willing to try it. I assume that the inner seal will butt up agianst the case- in other words it can not fall back into the case from being driven in too far.

Thanks again,
Dan

noonie

The shafts are very soft material, but are usually only damaged by trying to remove an old seal without the proper tool.
Have had to replace several and is a pita, replacements are at a junkyard or if your lucky a tranny repair place may have saved some.

You shouldn't damage the shaft by installing the seal, old seal will stop on a lip.

bruiser

I just took my shaft out on my 77 th350. It slides out without having to lower the transmission. First you get the pan & filter off. Then you remove 1 bolt that holds the lever that touches the rooster comb. Remove the wide clip on the selector shaft. Then remove the 11/16 nut on the selector shaft inside the transmission. The shaft should slide out with a little prying and turning.

...Roger...

No kidding ? For some reason I thought I had to drop the valve body to get it out , its been many a moon since I've removed a shaft. ( i have a auto tranny guy )

7T1vette

The inner seal will bottom out...no risk there. The valve body does NOT have to be dropped, but the detent spring/roller is bolted to it. However, you still have to drain the oil and drop the pan--and if it was sealed well, you don't really want to do that, do you?

I'd set odds of success with another seal at 90%.

jayfire

Here is a good place to buy tranny parts. The seals are .45 a piece, cork pan gaskets are only .74 a piece. I don't know what GM tool you were talking about, but they sell a tool to remove and install those seals. Here is the link: http://www.transmissionpartsusa.com/...als_s/4657.htm

jimvette999

If you have to remove the shaft, after rermoving the nut, take a file and clean up the area where the nut tightened against the shaft. Sometime it's slightly mushroomed and this bur will scratch the bore of the case up badly as you twist and slide the shaft out not to mention generally making it hard to remove the shaft at all. Hold the shaft on the outside when removing the nut on the inside or block selector (without bending) with heavy screw driver.

7T1vette

I believe that using a file will damage it more. Use some emery cloth or similar item to polish the shaft down smooth.

jimvette999

To clarify, the filing would be done on the burr, not the smooth portion of the shaft.