OMG!!! I just found out I have a TH400, not TH350!! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TIMSPEED · 01-23-2004, 03:38 AM

WHOA!!! All this time I thought I had a TH350...wow, should I be happy I have a TH400 instead of a TH350?

*1972C10* · 01-23-2004, 03:59 AM

Alot Of people say that if you have a 400 you will get quicket E.T.s from a th350 due to less rotating mass And If you have a 350 and your vehicle wiehgs under 3800 you can run faster with a glide due to less rotating mass

One of the things i dont like about a 400 is the fact that they wont Hold 1st gear friend of mine has one in a 94 isuzu and he cant get but maybe 5000 out of first gear before it will shift into second .. when the modulator looses vaccum it will shift into 2nd gear They make a shift kit to fix this but myself i prefer a 350 they dont need any mod to have a manual first

The 400 is a stonger unit thou .

1974StepSide · 01-23-2004, 06:33 AM

I didn't know I had a 400 either until my uncle was doing a brake job on my truck and he happened to see it. I was pretty happy to find out I had a 400, something different right...

greenhorn male · 01-23-2004, 01:11 PM

I thought GM mostly put the th400 on heavier duty trucks, but oddly enough my 87 Short 1/2T with a 305 has a th400 under it, too.

jared stewart · 01-23-2004, 01:39 PM

How do you tell the difference between a 400 and a 350?

greenhorn male · 01-23-2004, 02:03 PM

Try this link and click on the chart to enlarge it:

http://www.pro-built.net/index.cfm?fuseaction=idchart#

jared stewart · 01-23-2004, 02:07 PM

Thanks greenhorn. Great chart!

apstguy · 01-23-2004, 02:46 PM

How could you not know all this time? Just never look at it or what? Tim..... we need to get you glasses

MylilBowTie · 01-23-2004, 02:51 PM

Side view

MylilBowTie · 01-23-2004, 02:55 PM

Other side view.

MylilBowTie · 01-23-2004, 03:00 PM

Bottom view of factory deep metal pan.

r0lf- · 01-23-2004, 03:09 PM

The only thing about TH400's vs 350's is that they eat about 30 horses vs the 15 that the 350 does. Its due to it being heavier duty and being able to take about 500TQ stock

Id be excited, now you dont have to worry about busting your tranny when you get engine upgrades

Tom · 01-23-2004, 04:30 PM

They were standerd duty on big blocks, so this must mean you need a big block now

low 84 · 01-23-2004, 07:54 PM

i wouldn't bee too happy about having one. th350 is plenty strong enough for what you have and more. having the 400 in there is just eating up more power.

Blue Beard · 01-23-2004, 11:01 PM

Gee...........what gave you the first clue.......

*mike reeh* · 01-24-2004, 06:02 AM

yeah I just found out my soon to be "parts" burb has a 4L80E. I guess im stoked? either way its worth more than the 700r4 that I thought was in there. Hell I might even be able to get it to run off the stock computer in another vehicle. that would be cool. VSS, what else could it depend on? TPS, no big deal.. tach signal? no biggie. We'll see.

mike

87 Shortwide · 01-24-2004, 01:28 PM

Sure its not a TH375?

*1972C10* · 01-24-2004, 02:41 PM

Yeah thats a possibilty it could be a 375 it would look just like a 400 but have a small diamter output shaft like a th350

MylilBowTie · 01-24-2004, 06:17 PM

Look on this tag and tell me what you see. Would get a better picture but I dont have the camera to use any longer.

*mike reeh* · 01-24-2004, 06:53 PM

lilbowtie: how many bolts are on the tail shaft housing, in that pic? Is it 4 or 6? I dont know much about the th375. What case style does it use, the 350 or 400?

I would assume a 375 lives in a th350's case, or its own custom case. Either way, a th400 always has 6 bolt tail shaft housing. in a Hex shape. Thats the quickest way to identify the trannies, and is especially easy if you're looking for transfer case adapters

mike

*1972C10* · 01-24-2004, 06:54 PM

Thats a 400 i think he was sayin that other guy might have a 375 because some of them trucks did come with them .. youve got the shorttail 400 there

*1972C10* · 01-24-2004, 06:55 PM

375 uses a 400 case and has 6 bolts on the tail just like a 400 ill get a pic posted next time i go to the trans shop if anyone is interestd in seeing one ..

just like a 400 but it has a 350 style output shaft

gldevall · 01-24-2004, 07:37 PM

Hey Tim, you seem to know a good bit about these trucks and with all the trouble you have have with the flywheel, you never noticed the shape of the pan?

Lynx · 01-24-2004, 08:07 PM

Maybe someone snuck up on him in the middle of the night and switched it!

*1FaastC10* · 01-24-2004, 10:57 PM

Quote:

Originally posted by gldevall
Hey Tim, you seem to know a good bit about these trucks and with all the trouble you have have with the flywheel, you never noticed the shape of the pan?

i'm starting to wonder about that lately...

01-23-2004, 03:38 AM	#1
TIMSPEED Join Date: Jan 2003 Location: Modesto, CA Posts: 1,321	OMG!!! I just found out I have a TH400, not TH350!! WHOA!!! All this time I thought I had a TH350...wow, should I be happy I have a TH400 instead of a TH350? __________________ I have a few cars... See Them Here

01-23-2004, 06:33 AM	#3
1974StepSide Play it Loud... Join Date: Aug 2002 Location: East San Jose, CA Posts: 465	I didn't know I had a 400 either until my uncle was doing a brake job on my truck and he happened to see it. I was pretty happy to find out I had a 400, something different right... __________________ Big Moe =-=-=-= 1974 Cheyenne Super Stepside, 350/400, Hooker Headers, Flowmaster Mufflers... Needs new doors, fenders, hood, and paint. 1952 Chevy Pickup waiting to be brought back home!

01-23-2004, 02:03 PM	#6
greenhorn male Senior Member Join Date: Jan 2003 Location: Bay Area, Northern California Posts: 1,344	Try this link and click on the chart to enlarge it: http://www.pro-built.net/index.cfm?fuseaction=idchart# __________________ 03 Tahoe 72 GMC Super Custom 2500 Custom Camper, my reliable workhorse. Dual gauged tanks, dual battery trays.

01-23-2004, 02:46 PM	#8
apstguy LED King Join Date: Jan 2003 Location: Sacramento, CA Posts: 2,087	How could you not know all this time? Just never look at it or what? Tim..... we need to get you glasses __________________ Tyler 1985 C10 305 w/ Bowtie OD TH700R4 3.42 LSD 202,000 miles 2006 Ford Focus ZX3 5-speed Stick 2016 Chevy Spark EV Gone: 2002.5 VW GTI 24v VR6 Gone: 2008 VW R32

01-23-2004, 02:51 PM	#9
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	Side view __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

01-23-2004, 03:59 AM	#2
1972C10 Account Suspended Join Date: Dec 2003 Location: Texas Posts: 2,686	Alot Of people say that if you have a 400 you will get quicket E.T.s from a th350 due to less rotating mass And If you have a 350 and your vehicle wiehgs under 3800 you can run faster with a glide due to less rotating mass One of the things i dont like about a 400 is the fact that they wont Hold 1st gear friend of mine has one in a 94 isuzu and he cant get but maybe 5000 out of first gear before it will shift into second .. when the modulator looses vaccum it will shift into 2nd gear They make a shift kit to fix this but myself i prefer a 350 they dont need any mod to have a manual first The 400 is a stonger unit thou .

01-23-2004, 01:11 PM	#4
greenhorn male Senior Member Join Date: Jan 2003 Location: Bay Area, Northern California Posts: 1,344	I thought GM mostly put the th400 on heavier duty trucks, but oddly enough my 87 Short 1/2T with a 305 has a th400 under it, too.

01-23-2004, 01:39 PM	#5
jared stewart Silverado Stew Join Date: Jan 2004 Location: Ewing, MO Posts: 184	How do you tell the difference between a 400 and a 350?

01-23-2004, 02:07 PM	#7
jared stewart Silverado Stew Join Date: Jan 2004 Location: Ewing, MO Posts: 184	Thanks greenhorn. Great chart!

01-23-2004, 02:55 PM	#10
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	Other side view. __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

01-23-2004, 03:00 PM	#11
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	Bottom view of factory deep metal pan. __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

01-23-2004, 03:09 PM	#12
r0lf- Hotwheels? Join Date: Dec 2002 Location: Pleasant Hill, CA Posts: 1,145	The only thing about TH400's vs 350's is that they eat about 30 horses vs the 15 that the 350 does. Its due to it being heavier duty and being able to take about 500TQ stock Id be excited, now you dont have to worry about busting your tranny when you get engine upgrades __________________ 1978 Money Pit - CUSTOM DELUXE!!!!

01-23-2004, 04:30 PM	#13
Tom driving is in my blood Join Date: Dec 1999 Location: Mesa AZ Posts: 5,748	They were standerd duty on big blocks, so this must mean you need a big block now __________________ -78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle. -98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes. -02 Suburban 4x4: leveled front -CBR600F4i, CBR600RR, CBR1000RR, and standup skis DISCLAIMER: I cant spell for the life of me.

01-23-2004, 07:54 PM	#14
low 84 Registered User Join Date: Jan 2002 Location: Houston, TX Posts: 2,144	i wouldn't bee too happy about having one. th350 is plenty strong enough for what you have and more. having the 400 in there is just eating up more power. __________________ '51 F100, backhalf with a narrowed 9 and coil overs, 18.5" mickeys, monte front clip, +400" sbc in the works '05 1500 Crew Cab RIP '84 swb 5/7 drop, solid cammed 408 w/ fully ported dart heads, th350 w/ 10 inch hughes, 12 bolt w/ 3.73 richmonds and a locker '80 swb 4x4 in progress: 7" lift, 350 th350/np205, d44 and 1.5" ORD tie rod, 14BFF w/discs , armored diff covers, 40" MTR's

01-23-2004, 11:01 PM	#15
Blue Beard Registered User Join Date: Jan 2003 Location: Washington State Posts: 8,831	Gee...........what gave you the first clue....... __________________ 1970 Chev CST 2003 Harley Fatboy 1975 Chevrolet Step Van 1956 Chev Bel Air 1977 Blazer 2WD For Sale $3000.00 1978 Blazer 2WD For Sale $7000.00 1978 Silverado 2005 Monte Carlo



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01-24-2004, 06:02 AM	#16
mike reeh 5 day ban, learn to behave. Join Date: Nov 2002 Location: san diego, ca Posts: 683	yeah I just found out my soon to be "parts" burb has a 4L80E. I guess im stoked? either way its worth more than the 700r4 that I thought was in there. Hell I might even be able to get it to run off the stock computer in another vehicle. that would be cool. VSS, what else could it depend on? TPS, no big deal.. tach signal? no biggie. We'll see. mike

01-24-2004, 01:28 PM	#17
87 Shortwide Registered User Join Date: Nov 2002 Location: Wichita Ks Posts: 536	Sure its not a TH375? __________________ Daily Driver: 1992 Blazer dropped on rallys Project: 87 GMC shortwide, About to get a little boost

01-24-2004, 02:41 PM	#18
1972C10 Account Suspended Join Date: Dec 2003 Location: Texas Posts: 2,686	Yeah thats a possibilty it could be a 375 it would look just like a 400 but have a small diamter output shaft like a th350

01-24-2004, 06:17 PM	#19
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	Look on this tag and tell me what you see. Would get a better picture but I dont have the camera to use any longer. __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

01-24-2004, 06:53 PM	#20
mike reeh 5 day ban, learn to behave. Join Date: Nov 2002 Location: san diego, ca Posts: 683	lilbowtie: how many bolts are on the tail shaft housing, in that pic? Is it 4 or 6? I dont know much about the th375. What case style does it use, the 350 or 400? I would assume a 375 lives in a th350's case, or its own custom case. Either way, a th400 always has 6 bolt tail shaft housing. in a Hex shape. Thats the quickest way to identify the trannies, and is especially easy if you're looking for transfer case adapters mike

01-24-2004, 06:54 PM	#21
1972C10 Account Suspended Join Date: Dec 2003 Location: Texas Posts: 2,686	Thats a 400 i think he was sayin that other guy might have a 375 because some of them trucks did come with them .. youve got the shorttail 400 there

01-24-2004, 06:55 PM	#22
1972C10 Account Suspended Join Date: Dec 2003 Location: Texas Posts: 2,686	375 uses a 400 case and has 6 bolts on the tail just like a 400 ill get a pic posted next time i go to the trans shop if anyone is interestd in seeing one .. just like a 400 but it has a 350 style output shaft

01-24-2004, 07:37 PM	#23
gldevall Registered User Join Date: Mar 2003 Location: Walker, LA Posts: 2,925	Hey Tim, you seem to know a good bit about these trucks and with all the trouble you have have with the flywheel, you never noticed the shape of the pan? __________________ Gary -1986 SWB: lowered 4/6, SOLD!!! -Best 1/4 mile: 14.51 @ 91.01 MPH -2001 Pewter Tahoe, billet grill, Corsa Sport Cat-back, K&N FIPK SOLD!!! -2004 Z-71 Extended cab with a flowmaster, BDS 6.5", 3" BL, 35x12.5x18 Trail Grapplers on Pro-Comp 18x9 wheels

01-24-2004, 08:07 PM	#24
Lynx Registered User Join Date: Jun 2003 Location: Fort McMurray, Alberta, Canada Posts: 513	Maybe someone snuck up on him in the middle of the night and switched it! __________________ Ben 1983 Silverado SWB 305 2002 Silverado Extended Cab 5.3 http://members.shaw.ca/bkennett

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