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#1 |
Registered User
Join Date: Apr 2002
Location: Manitoba, Canada
Posts: 663
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Took my '76 on the highway the other day and I just couldn't get it to stay at highway speed. The trans kept slipping. I thought it was low fluid, so I checked and it was OK. Back on the highway again and it accelerated well, but it was revving really high. The next time I accelerated I paid more attention to the shifts and sure enough, I lost 3rd gear. So what is my plan? Is there any point in trying to fix this thing or is it off to the wrecker?
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Present: 2015 Tacoma. Yeah, not a GM, but I love it. 1969 GMC 32,000 - fix, drive, relax, fix... 2019 BMW R1250 GSA - Yahoooooooo 1979 Honda GL 1000 - retro touring at its best. Past: '05 Sierra 4x4 - Had 270,000 KM and running well when it was written-off by a stop sign runner. '94 F-150 from the "F word" company. I'll admit it...good truck. Sold what was left of it for $800 to a guy who came to pick it up at 11:00 PM with cash in hand. Hmm. '79 Sierra Grande (Black) organ donor - perfect rebuildable 4-bolt 350 and a good TH350. '76 Sierra Grande (Orange) - hate isn't too strong a word. Kid who bought it turned it into a hot rod. '68 C-10 R.I.P. - Dad's old truck...too far gone to resurrect. '59 C-50 - with hoist. Truck is gone, wife isn't. Nuff said. |
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#2 |
Account Suspended
Join Date: Oct 2002
Location: Elkhart, IN
Posts: 6,400
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again, try the correct forum.
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#3 |
Senior Member
Join Date: Sep 2004
Location: Terrell, TX
Posts: 1,967
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You've got a great tranny and they are not expensive to rebuild. I'd keep it and rebuild it. TH-350's can be made very tough and a shift kit will get you some thrills along with the return of third gear...
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Kelly '05 GMC Sierra SLE Z71 Bone stock except for new bed rail caps. |
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#4 |
Stepsides RULE
Join Date: Jul 2004
Location: Pineville, LA
Posts: 1,921
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yup definately get it rebuilt, TH350's are bulletproof, and when they do go, rebuild is *relatively* cheap.
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1981 Chevy C10 Custom Deluxe Stepside 350 V8, headers, side exhausts, 3-speed auto SOLD 1980 Chevy C10 Custum Deluxe Stepside 305 V8, Edelbrock Performer Intake, Edelbrock 1406 600CFM 4-barrel, TH350C. Bent rod. SOLD 1984 GMC Sierra Classic Longbed 6.2L Diesel SOLD 2009 Kawasaki KLX-250S too many mods for this signature 1999 Honda Accord EX 4-cylinder, 17" Motegi Wheels 215/45/17 Sumitomo tires, Tein S-Tech lowering springs, KYB GR2 shocks, Acura TL 20mm rear swaybar, debadged, blackhoused headlights, Short-Ram Intake Cardomain of the Accord |
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#5 |
Right turn Clyde
Join Date: Nov 2002
Location: Cincinnati, Ohio
Posts: 2,911
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TH350s are weak with any kind of hint of power especially in stock form. TH350Cs are even weaker. That said you can build up a th350 to handle some power but in stock form there isn't to much to be said for them in a heavy truck. This one probably has failed due to age and wear though. If you pull it out and have it rebuilt you should be able to save some money. Rebuild with new convertor should run about 500-700.00 depending on the area.
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1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI |
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#6 | |
Registered User
Join Date: Jul 2003
Location: Springfield,Mo.
Posts: 305
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Quote:
As a trans builder by trade,I completely disagree.A stock TH350(in good working order)will live a long,healthy life behind a mild bigblock.I can actually beef a 350 much more so than a 400,for much cheaper,billet aftermarket goods aside.I ran a Th350 with a hardened sprag gear,redline race clutches and steels,and a slightly modified pump in my mudracer,powered by a nasty 496 BB,with a 500hp shot of spray,and never hurt one tranny.This was in a 4800 pound truck.Please,don't be misinformed.Dollar for dollar,unless your truck already has a 400,the 350 is where it's at. For the record,350Cs have very few differences outside of the pump and convertor,and will accept all internals of a non lockup 350,so still worth building if you have a competent trans builder. |
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#7 |
7000 #'s of american IRON
Join Date: Dec 2004
Location: north tx
Posts: 883
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how close did you pay attention?
our truck has a 400, and i listen all i can and it only shifts twice and also revvs high. The truck has no tach, but it runs at 60 fine, so i think it's just common nature of the 400 and 350 that the 1-2 shift is inaudible and lack of overdrive just makes the engine seem abnormally loud (our truck mathematically runs at 2500 RPM at 60 with 4.10's and no OD). |
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#8 |
Right turn Clyde
Join Date: Nov 2002
Location: Cincinnati, Ohio
Posts: 2,911
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There isn't to much you can say about what I have experienced in the th350s Ive had. Mudracing with a built transmission isn't like taking it to the track with slicks and seeing how long it holds up. There will be a lot more stress on the th350 then it will ever see in the mud.
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1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI |
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#9 | |
Registered User
Join Date: Jul 2003
Location: Springfield,Mo.
Posts: 305
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Quote:
I'm sorry you've had bad experiances with this trans,sounds like your builder wasn't on his game. |
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#10 |
Registered User
Join Date: Sep 2004
Location: San Antonio, TX
Posts: 39
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bloertcher , would you agree that bluec10 should check his governor?
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'78 GMC 5.7L TBI, 4x4 longbed, 56" rears, 52" fronts '01 F350 6.8L Crew Cab 4x4 Longbed |
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#11 |
Right turn Clyde
Join Date: Nov 2002
Location: Cincinnati, Ohio
Posts: 2,911
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Yes, you are right about there not being a transmission guy worth anything around here or that I have ever found. Its almost made me seriously look at rebuilding one myself to get the feel for it. There again I don't have all the tools or parts washers and things like that to do a good job nor the money to blow just to experiment. I haven't found anyone I've even thought would be willing to help out with me rebuilding one. Everyone is in it for the money, I know nothing comes free. But its like 1200.00 for 3 month warranty on a stock th350 rebuild with convertor non lockup. In six months I had it two weeks tops, the rest of the time in was in the shop with something wrong. Driving down the road and the governor cover with the clip installed fly's out dumps all the transmission fluid on the ground. They didn't rebuild it or even look at in just installed the governor and cover with the clip put trans fluid in it and said its done. Slipping, bad convertors, warped valve bodies, front pumps. The said rebuild at 1200.00 didn't included "hard parts" other than pump and convertor just the standard "soft" parts.
Getting back on topic, I would drop the transmission pan and inspect it. Look to see how much stuff and shavings are in the pan. More likely than not it is just in need of a rebuild. Possibly look at the governor but I don't see why that would make it slip.
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1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI |
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#12 |
Senior Member
Join Date: Sep 2004
Location: Terrell, TX
Posts: 1,967
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$1200 fpr a 350 rebuild? You sure that's not for a 200/700 series? That's double what a firm shifting tranny rebuild costs here (for a 350). I mistakenly had a four speed rebuilt [2004r in an MCSS] once and it cost me $1600...never again!!
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Kelly '05 GMC Sierra SLE Z71 Bone stock except for new bed rail caps. |
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#13 |
Right turn Clyde
Join Date: Nov 2002
Location: Cincinnati, Ohio
Posts: 2,911
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This was a TH350 that didn't have a lockup torque convertor just a basic old style TH350 with a 9in tailshaft. Nothing about it new or warent the 1200.00 dollar for a stock rebuild or only to drive it two 2 weeks out of six months. But that is all combined in the two weeks that was spread out in the six months. Shop look like a good one, had a lot of city vehicals and taxi there. Made sence to me that they would be good place to have do it.
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1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI |
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#14 |
Senior Member
Join Date: Mar 2003
Location: St robert Mo
Posts: 2,001
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Can you not buy one for less thatn 1200.00 I dont have my summit but I swear they wee like 700-800 for a nice one from them.
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1968 c10 lowered 3" 4" 355/Th400 built by Hatfield racing in joplin MO |
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#15 |
Right turn Clyde
Join Date: Nov 2002
Location: Cincinnati, Ohio
Posts: 2,911
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Whats the question? I could have bought a transmission from Summit. I didnt know it was going to be that much going into this, it started at 800.00. I dont think I would care to much if I had to ship the transmission back to the factory if anything should go wrong plus the shipment fees. Me being out a vehical to drive, down time, me having to remove and install it, fluid and all that stuff.
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1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI |
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#16 |
Registered User
Join Date: Jul 2003
Location: Springfield,Mo.
Posts: 305
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Man,$1200.I was born in the wrong place!Unfortunately,this world is made up of a lot of money hungry people who just want the check.I have had trannys come back to me before,(being human and all,I screw up once in a while
![]() ![]() P.S.Yes,he should look at the governer,but this would most likely be a band-aid fix.Sounds to me like it's time for a rebuild. |
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#17 |
Registered User
Join Date: Sep 2004
Location: Huntsville Alabama
Posts: 6
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just wanted to add this...... basic garage built th350 with hardened sprag,good clutches,steels,manual valave body. This has lived behind my 355 solid roller motor + 150 nitrous works kit for the last 3 seasons. This is in a 3600 pound street driven 78 camaro that runs a pretty consistant 10.60-70@128.
I say the th350 is pretty dang stout. |
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#18 |
Senior Member
Join Date: Sep 2004
Location: Terrell, TX
Posts: 1,967
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There's nothing weak about a 350 unless a moron built it. I've had one behind my 355 in the Elky for the last five years...it was rebuilt in 1997 (before I bought the truck). I've had several 350's over the years and the only tranny that's stronger is a 400.
I think the 80's 4-speed trannies are the junkers of the lot (200's and 700's)...you couldn't pay me to take either one and install it (I'd sell it on ebay though!). I have owned [1] 200 and [2] 700's so I speak from experience. The 80's were the decade of the least quality from GM as well as many a stop-gap emissions fix on the motors. I tend to stay very far away from any motors/tranny built from 1980-1987.
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Kelly '05 GMC Sierra SLE Z71 Bone stock except for new bed rail caps. |
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#19 |
Senior Moment
![]() Join Date: Mar 2002
Location: Pittsburg Ca
Posts: 4,133
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We have A-1 Transmission in Antiock Ca, here in THE GOLDEN STATE (people think everything is gold) that does a built 350 with shift kit, converter and FULL 1 year warrantee for $650 (you install) He tells me it will hold up to my mild 454 with no problem. The 454 just went in last week so we'll see but I have faith. They’ve built transmissions for me before and never had a problem. Hope you can fine a good reliable shop to help you out.
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1970 CST LS 1 6 speed Ford 9 inch Detroit Tru Track, Dakota Didgital, Vintage Air, QA1 Coil Overs Front & Rear Lots of FUN 2013 GMC PU, Oldest Son 71 GMC LWB. QA1 Suspension, Angry SB. Youngest Son 2019 GMC Diesil Dually. Youngest Son 2017 Toyota SUV Daughters car 2018 Traverse , Wife’s Ride Pittsburg Ca 94565 |
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#20 |
Registered User
Join Date: Nov 2003
Location: Grants PassOregon
Posts: 335
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I would rebuild yer TH350. I had one with a 203 TC behin my BBC 427 for a year, an I wailed on that tranny. No problems. they hold up quite nicely if they are built right. and they should be in expensive to build and rebuild. just my .02$
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The Devil ![]() 1983 ONE TON 454/400/208 11" of lift on 44's |
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#21 | |
Registered User
Join Date: Jul 2003
Location: Springfield,Mo.
Posts: 305
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Quote:
By the way,don't you just hate the tourque of that 454? ![]() |
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#22 |
Registered User
Join Date: Mar 2003
Location: Liège , Belgium
Posts: 263
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hi all ,
I got the same slipping problem on my 1977 Impala ( straight six 250ci / TH350 ). I just did a good oil & filter swap on the tranny and I drove it further 10 000 miles without any problem. try something : while you drive at least at 30 MPH in "D" mode , try to put your tranny in "N" , while you're driving , and put it back to "D" this is what I did , and the third speed shifted without problem , for about a 30 miles driving , before it did it again... ![]() just my 02 cents , before you throw it all open ![]() the Baron
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1982 Suburban 2WD , 260ci Olds engine,TH400 , will get a 1979 front clip , might be ready in ... 2016 1985 Chevy Van ( 305/350 ) , "Kellogg" equipped , my actual D.D. 1960 Girl Friend , frame still good , body has some dents |
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