Help determine my tranny - The 1947 - Present Chevrolet & GMC Truck Message Board Network

*Robo_bot* · 04-09-2004, 12:48 PM

i bought this tranny from my buddies uncle he said it was a TH400 but it doesnt measure right its an inch longer then a TH400 and stuff heres the numbers on the Vin Tag

B 73C 383 C
73-BC 149556

can someone help me find out wether it is a TH400 or TH375?????

Thanx

swdobbs · 04-09-2004, 01:12 PM

This is from memory and therefore I maybe wrong but the rule of thumb I use is

6 bolts on the tailhousing = th400
4 bolts on the tailhousing = th350

top of bellhousing where it mounts to the block has a valley its a from an olds/buick/pontiac......

top of bellhousing is peaked its a chevy.

hope this helps

swdobbs.....

orange72350 · 04-09-2004, 02:36 PM

here.....check the pan shape.. it may be a th400 with a longer tailshaft tooo. not really sure. are pics a possibility???

Longhorn Man · 04-09-2004, 10:40 PM

TH350 has a kick down cable, TH400 does not.
There were more than one length on the trannys, so if your compairing it to just one measurement, then that won't rule out anything.

John Engelberg · 04-09-2004, 11:10 PM

I dont normally do anything but read here but I thought I could help. I noticed that you ask about a 375 turbo, well that trans was a cadillac trans. Same style bellhousing with a 400 front housing,modulator on the side behind the bellhousing.this trans has a longer tail shaft than a normal 400 and the output shaft is not the same as a 400 it uses a 350 yoke because of its shaft size. I hope this will help you to identify your unit.
John

Longhorn Man · 04-09-2004, 11:33 PM

I didn't even catch that.
If it has the chevy bolt pattern, then it is not a caddy tranny, they used the BOP pattern.

Chevy67Tk · 04-10-2004, 12:30 AM

Use the pan chart that Orange posted

If the numbers you posted are on a 400 they match up to a 1973 to 1974 BOP model that was use on all other than 455 V-8 Century & Reagal or Hi – Perf.

The 375 was used on chevys also and will be marked on the bottom of the tail shaft THM-375

mooneyes · 04-10-2004, 09:25 AM

dad had a 375 t in his chevelle years ago..you think its a 350t until u pic it up seems as heavy as a 400t

04-09-2004, 12:48 PM	#1
Robo_bot Account Suspended Join Date: Feb 2004 Location: Kelowna BC Canada Posts: 481	Help determine my tranny i bought this tranny from my buddies uncle he said it was a TH400 but it doesnt measure right its an inch longer then a TH400 and stuff heres the numbers on the Vin Tag B 73C 383 C 73-BC 149556 can someone help me find out wether it is a TH400 or TH375????? Thanx

04-09-2004, 01:12 PM	#2
swdobbs Registered User Join Date: Oct 2002 Location: MT Posts: 98	TH400 This is from memory and therefore I maybe wrong but the rule of thumb I use is 6 bolts on the tailhousing = th400 4 bolts on the tailhousing = th350 top of bellhousing where it mounts to the block has a valley its a from an olds/buick/pontiac...... top of bellhousing is peaked its a chevy. hope this helps swdobbs.....

04-09-2004, 02:36 PM	#3
orange72350 Registered User Join Date: Jan 2003 Location: Cold, Snowy High Level, Alberta Canada Eh Posts: 394	here.....check the pan shape.. it may be a th400 with a longer tailshaft tooo. not really sure. are pics a possibility??? __________________ 2003 yamaha raptor. Stock, but it still hauls!!!! 2000 skiddo mxz 700. Camoplast 1.5 inch track, jaws twin pipes, b+b can, custom built and weighted clutch, wiseco piston, high comp heads. its very fast. wow. 72 c-10 longbox. Bright Orange. Brand new 350, rv cam, performer intake, qjet, headers, 2 1/2 inch exhaust into hooker areo chamber mufflers. Body work coming soon. "dont let yer mind wander, its to little to go places by itself." "Forget the herse, cause i'll never die"-ACDC Back In Black "If It's To Loud, Yer Just Too Old" "I Love Anything Fast Enough To Do Something Stupid In" "Instant idiot, just add beer!!""

04-10-2004, 12:30 AM	#7
Chevy67Tk Registered User Join Date: Mar 2003 Location: PA Posts: 349	Use the pan chart that Orange posted If the numbers you posted are on a 400 they match up to a 1973 to 1974 BOP model that was use on all other than 455 V-8 Century & Reagal or Hi – Perf. The 375 was used on chevys also and will be marked on the bottom of the tail shaft THM-375 __________________

04-10-2004, 09:25 AM	#8
mooneyes Registered User Join Date: Jan 2002 Location: Slippery Rock PA USA Posts: 1,692	dad had a 375 t in his chevelle years ago..you think its a 350t until u pic it up seems as heavy as a 400t __________________ Ken Lyons, Slippery rock pa 68 short step 327 t10 4 gear 72 2wd blazer project 70 lwb 305/700r driver 78 caprice project 02 cavalier D.D ( hate it!!)

04-09-2004, 10:40 PM	#4
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	TH350 has a kick down cable, TH400 does not. There were more than one length on the trannys, so if your compairing it to just one measurement, then that won't rule out anything.

04-09-2004, 11:10 PM	#5
John Engelberg Registered User Join Date: Feb 2003 Location: Florida Posts: 2	I dont normally do anything but read here but I thought I could help. I noticed that you ask about a 375 turbo, well that trans was a cadillac trans. Same style bellhousing with a 400 front housing,modulator on the side behind the bellhousing.this trans has a longer tail shaft than a normal 400 and the output shaft is not the same as a 400 it uses a 350 yoke because of its shaft size. I hope this will help you to identify your unit. John

04-09-2004, 11:33 PM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	I didn't even catch that. If it has the chevy bolt pattern, then it is not a caddy tranny, they used the BOP pattern.



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