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how to tell the diff between turbo 350&400 trans? (Read 879 times)
derek
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Si Fallor, sum
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how to tell the diff between turbo 350&400 trans?
08/28/06 at 21:13:03
 
I have a friend with a 73 cadillac with trans probs.  He has lost third gear (drive).  He still has 1st and 2nd though.  We can't find out what kind of trans it is.  Is it a 400 like the 90 SS's or is it a 350?  How can you tell the difference?  Thanks

Derek
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Re: how to tell the diff between turbo 350&400 tra
Reply #1 - 08/28/06 at 22:33:58
 
You can tell by the shape of the pan, but I forgot which is which! Sad

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Re: how to tell the diff between turbo 350&400 tra
Reply #2 - 08/28/06 at 22:49:17
 
them older caddys have those big engines like 510's or something like that.. i'd guess that it has a 400.. Like he said look at the pan and describe to us..
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Re: how to tell the diff between turbo 350&400 tra
Reply #3 - 08/28/06 at 22:51:21
 
being a 73 it may be a B.O.P 400 but you should be able to tell by the pan
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beat454
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Re: how to tell the diff between turbo 350&400 tra
Reply #4 - 08/29/06 at 02:13:27
 
Doesn't it usually say it on the pan??? Huh

I know mine say Turbo Hydromatic 400 right on the pan. Undecided
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Re: how to tell the diff between turbo 350&400 tra
Reply #5 - 08/29/06 at 11:08:56
 
The 350 pan is basically square with one corner cut off at about 45 deg. The 400 has a kinda kick-out on it, more rounded corners. I think the 350 has a 4-bolt tailhousing, and the 400 has a 6-bolt. There is a difference in the modulator covers too I believe. 400 bolted on cover & 350 cover held on with a wire bale maybe  Huh I'm going from my fuzzy memory here  Roll Eyes so don't hold me to the accuracy of this info. I'm SURE someone will correct me if (when) I'm confused  Wink

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Re: how to tell the diff between turbo 350&400 tra
Reply #6 - 08/29/06 at 15:45:01
 
Look here:

http://www.442.com/oldsfaq/oftrn.htm

It will tell you more than you want to know, but it's a great information site for everything to do with GM auto trannys
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derek
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Si Fallor, sum
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Re: how to tell the diff between turbo 350&400 tra
Reply #7 - 08/29/06 at 16:07:53
 
Thanks everyone.  I believe it is a 400 trans.  Does anyone know of differences in the years they made these?  He found an early 90's 400 just like the ones in the 90SS's.  would this trans go right in?  the caddy is RWD with a 472ci motor.  the trans is for a RWD 454 chevrolet.  thanks for all your help again!

Derek
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Re: how to tell the diff between turbo 350&400 tra
Reply #8 - 08/29/06 at 19:22:18
 
Welcome back Derek
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Re: how to tell the diff between turbo 350&400 tra
Reply #9 - 08/29/06 at 21:33:23
 
I don't think it will work the 472 has a differen't bell housing  Winkthat is were the B.O.P tranny comes in.
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Re: how to tell the diff between turbo 350&400 tra
Reply #10 - 08/31/06 at 01:49:28
 
2turboss wrote on 08/28/06 at 22:51:21:
being a 73 it may be a B.O.P 400 but you should be able to tell by the pan


Ding!  ALL 73's were BOP 400's. (BOP = Buick-Olds-Pontiac)  (Except the ElDorado which was the FWD THM425 with the Morris Chain, sister to the Olds Toronada and Buick Rivera Wink)

2turboss wrote on 08/29/06 at 21:33:23:
I don't think it will work the 472 has a differen't bell housing  Winkthat is were the B.O.P tranny comes in.


Ding!  A Chevy 400 will not plug and play... only the two bottom bolts will bolt up and you will eventually break the bellhousing if you do that!

The Chevy THM400 is worth a few hundred bucks for a core as they are going extinct from all the race cars eating them up.

The Caddy BOP tranny is worth $50 to $100 core as it is only in demand now that people mill the bellhousing completely off and bolt a steel Chevy bellhousing directly to the front pump.  It is about a $300 or so conversion so this is subtracted from the value of the core.

There are probably more than 200 BOP THM400's left out there for every Chevy THM400 that you will see.
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Re: how to tell the diff between turbo 350&400 tra
Reply #11 - 08/31/06 at 01:50:55
 
This thread should be in the GM Tech rather than the 454SS Tech shouldn't it?  Huh
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