Changing lower transmission bush? (auto)

SouthJersey400i · Jan 19, 2008

There is a bushing on the lower side near the back of the auto transmission. It is pressed into the extension piece that adapts the GM tranny to the torque tube. It is mounted between an adjustable clevis. Part #105634 and called an Estenblock (must be Norther Italian!) That intro was just to be sure we talk about the same bushing.

Mine is old an swollen with oil. I have the new part. Has anyone changed this bushing without pulling the housing off the back of the transmission, which I know is a lot of work. It is in a bit of small area but with the right pusher and large bush to press into it seems possible. I'd like to hear from anyone that has done it in place. If you have changed the bushing with the transmission out of the car, let me know how hard it was to press out and in.

I look forward to some advice.
Ken

simonc · Jan 21, 2008

I've done this and it is a job I swore I would never do again. My rubber mounting was swollen and looked in terrible condition, yet frankly when I removed it it was still sound except for the ends - maybe 80 or 90% OK and just swollen on the edges. I suggest you cut off the swollen end bits with a sharp knife so it looks tidy and then forget it. But if you must do this....

I sued a large socket on one side that rested on the carrier, a smaller one that fitted the outer sleeve of the rubber being on the other side, and then put a long bolt with some thick washers between the two and did up the bolt until the bush was pushes through. All sounds very simple but it isn't. I did this about 5 year sago and I recall it took me all day (and I mean an 8 hour day) to do this. The car was up on 4 axle stands and I was lying n the ground underneath the car. It really was a very sole destroying job and a waste of time.

I should say I am an experienced mechanic and have had the engine & box out subsequently, rebuilt them both myself and there isn't much on my 400 that hasn't been apart in the past 10 years.

As k me shall I take the engine out to change the head gaskets and I say yes, can I rebuild the suspension on my driveway in the rain- yes, shall I change the rear gearbox mounting in situ - NO!

Now you will probably go and do it and then say 'he was right you know'

SouthJersey400i · Jan 22, 2008

Simon
Your reply is exactly what I was looking for. I listen to all of the replies on this board; some I ignore others I don't. I am not ignoring yours. The problem is that minor oil leakage "up front" soaks this bushing and swells the outer portion just as you described. The swollen bit more or less fell off on one side and is intact on the other. Based on your input, I will look for a way to shield the bushing from getting soaked in oil, maybe a improvised plastic cap. Eventually the rubber that is doing the work in the center of the bushing will degrade. I figure this is a 1-2 year preventative measure. I will eventually need to replace the rear seal on the tranny and once the tail piece is off this is a piece of cake with a hydraulic press.

The procedure you described is exactly what I was going to attempt. I did not have the exact size sockets so I tried to just see how much give the bushing had with a "drift", but it did not budge and I gave up. I'll put this on the list for winter of 2009 or 2010.

Thanks
Ken

brettski · Jan 23, 2008

yup, washers and threaded rod. it's a bastard even with a lift.

It's Ross · Jan 23, 2008

When removing recalcitrant suspension bushings I've found that the "smokewrench" is your friend. Burn out the rubber and knock out the inner sleeve, then cut through the outer sleeve relieving it's grip. Freezing the new bushing before installing helps get it in.

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