Replace "case extension" in automatic? Has anyone done it?
Thread Starter
Instructor
Joined: Mar 2001
Posts: 199
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From: Canyon Lake California
Replace "case extension" in automatic? Has anyone done it?
I just called my local Chevy dealer to see if he had the rear seal and bearing for the output shaft for my '88 automatic trans (THM 700-R4). He said that Chevy offers the entire "case extension" that comes with the seal and bearing already installed. I don't remember reading about anything like that in this forum. He said the GM part number is 24201517. List price is $115.79.
Before I go ahead and buy this part, I was hoping someone on this forum could provide some advice on whether or not this is the way to go.
Thanks in advance for your feedback.
Greg Sullivan (Canyon Lake, CA.)
Before I go ahead and buy this part, I was hoping someone on this forum could provide some advice on whether or not this is the way to go.
Thanks in advance for your feedback.
Greg Sullivan (Canyon Lake, CA.)
Melting Slicks
Joined: Aug 2001
Posts: 2,516
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From: Lockport NY
Re: Replace "case extension" in automatic? Has anyone done it? (Greg's '88)
Last time I checked, the bushing & seal were still available separately...
Any good trans shop can replace them in-car, but you can also pull the extension and have it done...
Having said that, if it was me, I'd get that new tailshaft housing...You can always throw it on any 700R4 and sell it for a Corvette trans...Uh, I mean, save it for a spare...Yeah, that's it... :crazy: :D
...And GMPartsDirect has it for $66...
[Modified by Rich B., 8:54 PM 7/16/2002]
Any good trans shop can replace them in-car, but you can also pull the extension and have it done...
Having said that, if it was me, I'd get that new tailshaft housing...You can always throw it on any 700R4 and sell it for a Corvette trans...Uh, I mean, save it for a spare...Yeah, that's it... :crazy: :D
...And GMPartsDirect has it for $66...
[Modified by Rich B., 8:54 PM 7/16/2002]
Thread Starter
Instructor
Joined: Mar 2001
Posts: 199
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From: Canyon Lake California
Re: Replace "case extension" in automatic? Has anyone done it? (Rich B.)
Rich B.
Thanks for your info. I didn't even know about GMPartsdirect.
I just visited their web site, entered the part number and bingo!
Let's see...$116 or $66 for the same part....I hate tough decisions like this! :yesnod:
Thanks for your info. I didn't even know about GMPartsdirect.
I just visited their web site, entered the part number and bingo!
Let's see...$116 or $66 for the same part....I hate tough decisions like this! :yesnod:
Melting Slicks
Joined: Aug 2001
Posts: 2,516
Likes: 0
From: Lockport NY
Re: Replace "case extension" in automatic? Has anyone done it? (Greg's '88)
I use them for price checks, but I order from 18carfan (Jeff Kopp)...
GMPartsDirect has an unconventional S&H policy...
Try Jeff -
Jeff Kopp
Superior Chevrolet
Wholesale Office - Parts Department
800-728-8267 913-384-3115
"Superior Chevrolet Parts Department"<superchevyparts@worldnet.att .net>
GMPartsDirect has an unconventional S&H policy...
Try Jeff -
Jeff Kopp
Superior Chevrolet
Wholesale Office - Parts Department
800-728-8267 913-384-3115
"Superior Chevrolet Parts Department"<superchevyparts@worldnet.att .net>
Safety Car
Joined: Jan 2001
Posts: 4,387
Likes: 691
From: Boise ID
Re: Replace "case extension" in automatic? Has anyone done it? (Greg's '88)
Did mine this spring. Took the case to the transmission shop and for $35 they pushed in a new bushing and included all the o-rings and seals. :D
Instructor
Joined: Aug 2001
Posts: 138
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From: upatate ny
Re: Replace "case extension" in automatic? Has anyone done it? (Greg's '88)
I think mine might be bad too. How can you tell?
im getting a whining \rattly noise from that area and was wondering of it is the tail shaft or u joints.
I havent taken out the shaft yet the prob just started
Please help
im getting a whining \rattly noise from that area and was wondering of it is the tail shaft or u joints.
I havent taken out the shaft yet the prob just started
Please help
Thread Starter
Instructor
Joined: Mar 2001
Posts: 199
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From: Canyon Lake California
Re: Replace "case extension" in automatic? Has anyone done it? (daves87)
Dave's 87
I am trying to fix two problems by changing the rear seal and bushing. My 88 has a high speed (above 75 MPH) vibration that I haven't been able to cure. I've tried wheel bearings, tires, u-joints, and drive shaft balancing. All that is left is the tail shaft of the trans. It is leaking, so that tends to indicate that the bearing is shot (165,000 miles). The splined output shaft of the tranny wobbles about 1/4 inch in any direction. I don't think that is normal.
Good luck with yours. You may want to post your question in a new topic so more people will see it.
Greg Sullivan
I am trying to fix two problems by changing the rear seal and bushing. My 88 has a high speed (above 75 MPH) vibration that I haven't been able to cure. I've tried wheel bearings, tires, u-joints, and drive shaft balancing. All that is left is the tail shaft of the trans. It is leaking, so that tends to indicate that the bearing is shot (165,000 miles). The splined output shaft of the tranny wobbles about 1/4 inch in any direction. I don't think that is normal.
Good luck with yours. You may want to post your question in a new topic so more people will see it.
Greg Sullivan
Instructor
Joined: Aug 2001
Posts: 138
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From: upatate ny
Re: Replace "case extension" in automatic? Has anyone done it? (Greg's '88)
Ive got some play in mine as well not quite 1/4 inch but close.
I tried the same in my truck and there was SOME play but nothing like the vette. Thanks for the reply. good luck to you as well
:seeya
I tried the same in my truck and there was SOME play but nothing like the vette. Thanks for the reply. good luck to you as well
:seeya
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Melting Slicks
Joined: Aug 2001
Posts: 2,516
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From: Lockport NY
Re: Replace "case extension" in automatic? Has anyone done it? (Greg's '88)
The splined output shaft of the tranny wobbles about 1/4 inch in any direction. I don't think that is normal.
BTW: The bushing wall is only like 3/32" thick...Sounds like yours is eating aluminum by now...A good flush would be indicated...
Better check that shaft good...Make sure there's no rough edges...
Instructor
Joined: Aug 2001
Posts: 138
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From: upatate ny
Re: Replace "case extension" in automatic? Has anyone done it? (Rich B.)
Thanks Rich,
looks like ill be ordering the case too. fun fun fun...
It doesnt look like you need to remove the tranny to accomplish this? Is this right?
looks like ill be ordering the case too. fun fun fun...
It doesnt look like you need to remove the tranny to accomplish this? Is this right?
Thread Starter
Instructor
Joined: Mar 2001
Posts: 199
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From: Canyon Lake California
Re: Replace "case extension" in automatic? Has anyone done it? (Rich B.)
Rich B.,
Thanks for your suggestions. When the drive shaft was serviced 4 months ago (balanced, straightened, new u-joints), I was told that there was some wear on the shaft that inserts into the trans. They said they were able to take care of it. I will give a closer look into old extension piece to see if the bushing is completely gone.
I'm hoping that the new bushing and seal will finally solve the high speed shakes.
When I finally get the new extension (with new seal and bushing) installed, I'll update the forum so others can learn from my experience.
Greg Sullivan
Thanks for your suggestions. When the drive shaft was serviced 4 months ago (balanced, straightened, new u-joints), I was told that there was some wear on the shaft that inserts into the trans. They said they were able to take care of it. I will give a closer look into old extension piece to see if the bushing is completely gone.
I'm hoping that the new bushing and seal will finally solve the high speed shakes.
When I finally get the new extension (with new seal and bushing) installed, I'll update the forum so others can learn from my experience.
Greg Sullivan
Melting Slicks
Joined: Aug 2001
Posts: 2,516
Likes: 0
From: Lockport NY
Re: Replace "case extension" in automatic? Has anyone done it? (daves87)
It doesnt look like you need to remove the tranny to accomplish this? Is this right?
Safety Car
Joined: Feb 2002
Posts: 4,286
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From: Guam
Re: Replace "case extension" in automatic? Has anyone done it? (Rich B.)
Rich B. is correct on what to remove. Don't forget that you need to remove the exhaust also. However, I would replace the case extension assembly and not just the bushings and seal. Normally, when you get major vibration, the bushing is long gone and the case extension is already damaged. To save the hassle , I would advise buying the entire case extension anyway even if the case is okay. As for putting the old one on a 700r4 from another car and selling it as a vette trans, you may not be ablle to do that since the output shaft on many applications are different. Even the transmission pans are different on most applications. And if you remove the pan, you will see that the valve body is entirely different. However, you can put a 700r4 from another application in the vette. I did it with a few modifications such as cutting the output shaft and adapting the speed trans assembly. It is possible to do.
Let us know how it turns out.
:cheers:
Let us know how it turns out.
:cheers:
Melting Slicks
Joined: Aug 2001
Posts: 2,516
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From: Lockport NY
Re: Replace "case extension" in automatic? Has anyone done it? (Sharky Guam)
Don't forget that you need to remove the exhaust also... :cheers: