Cali4nia Monte Posted March 21, 2007 Share Posted March 21, 2007 Ok here's the deal, last month we purchased a new B&M TH350 from our local speedshop. We have bought alot of stuff from them and they are quite aware of what we have under the hood, the old tranny had no problems other then leaking like a sieve all over our driveway, and the bell housing is cracked which is why we didn't just have it rebuilt. So we got new B&M #1 installed and right off the bat we have NO 2 & 3 gears at all. Speedshop and B&M say bring it back....so we did. Now we put leaking old original tranny back in while waiting for B&M to ship us another new one and again it works fine. B&M tranny #2 has shown up so out goes the old and in with the new. It seemed to worked fine for about a week and now its slipping. Mike is ready to just scream....so we take it to a local transmission shop and they said....its internal...second gear is gone, and I can't remember what the part is they think went. Mike tells them whats been going on and they don't think its anything we did. Anyhow now B & M is trying to tell us that the TH350 is only rated for cars up to 325 hp....the speedshop and the tranny shop are like "No way we've put them in cars with over 400 and not had any problems." Our engine has 377 hp, and I think they are trying to get out of the warranty on it. So my long winded questions is "What is your opinion on how much HP will a TH350 take?" Thanks for your intake, Jaylene Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted March 21, 2007 Share Posted March 21, 2007 We have a 434 small block in front of a turbo 350 and had a 406 in front of it before that it has a 2400 stall converter and a shift kit no internal work has been done to it. The 434 is over 500 hp. I know guys that run big blocks with turbo 350s Quote Link to comment Share on other sites More sharing options...
Guest Posted March 21, 2007 Share Posted March 21, 2007 I had a Fairbanks TH350 in a 77 blazer. 450 hp. 454, 1 ton axles, 488 gears and 38" swampers. That trans took a beatin and never left me stranded. Quote Link to comment Share on other sites More sharing options...
Heckeng Posted March 21, 2007 Share Posted March 21, 2007 That is unbelievable. I've always had good luck with B&M, and have heard good things about their transmissions. Very strange. I have a 454 with somewhere around 450-500hp, and probably around 500-550 lbft and I've always run th350s and never had bad luck. I have a knowledgable transmission mechanic friend who builds them with just a few hardened parts and they've been fine. B&M owes you guys MAJOR apologies and a new super-ultra-whamodime tranny that they KNOW will work. That is rediculous. For some background on your combo, What is your rear gear? Do you have the vacuum modulator hooked up? What is your torque converter rated at? Quote Link to comment Share on other sites More sharing options...
Cali4nia Monte Posted March 21, 2007 Author Share Posted March 21, 2007 Mike went to bed already, but this is what I know about the car New GM 4 Bolt main with one piece rear main seal. Forged steel crankshaft w/3.480 stroke, micro polished chamfered, balanced with balancer and flex plate New 4340 steel "I" beam connecting rods with ARP bolts. Hypereutetic flat top piston 9.1 to 1 compression and single Moly piston ring New Hydraulic roller cam and lifter set. .501"/.512" lift, 224/230 degrees duration at .050" 111 lobe separation. Full aluminum roller rocker arms 1.5 to 1 ratio New performer cast iron cyclinder heads, slightly modified to match cam profile, with 2.02 intake and 1.60 exhaust, stainless valves. Double roller timing gear set Hardened push rod set. Edelbrock Endura Shine intake manifold (the Endura Shine was a surprise, I called the machine shop building the engine and had them add that, it was my early Christmas present to him since the motor was delivered on 12/22) A Holly 650 dual feed carb. It has 377hp and 385 Torque. As far as the rear end...we have not done anything to it yet it was next on Mikes list. So I am guessing it is just the stock rear end for the 71, because nothing else on the car had really been modified....mostly just mickey moused. They did things like gob clear silicone caulking all around the windows...and cut a hole in the grill because the hood latch didn't quite pop up high enough and it would be tight to get it open. I am not sure about the vacuum modulator? Is that the charcol canister thing at the front of the engine? Our torque converter is a 3000 stall speed, the owner of the speed shop sold it to Mike with the 1st tranny. We were originally going to just get a 2500 because the 2100 was driving me crazy lunging at a stop, but then they gave us a killer deal on the 3000 so we went with it instead. The owner of the transmission shop said he has become more and more dissatisfied with B & M and wont use them anymore, he says they have been bought out and are becoming very corporate. He called and talked to them for us and said that it sounds like it could be a fight to get them to warranty this second tranny. We have less then 50 miles on it...we had only made some short little trips to the hardware store and back. Well I don't know if I answered your questions or not....but at least I have heard from a few of you guys. Oh yeah I remembered the part he said the thought went...the sprag? Anyhow its late. Thanks again for the reassurances, Jaylene Will keep you all posted, as I am sure members would want to know how B & M handles this. Funny I guarantee the funky, leaking, cracked, old stock tranny could go right back in and work like a dream, as it has since we put the new engine in last December. Quote Link to comment Share on other sites More sharing options...
Guest Posted March 21, 2007 Share Posted March 21, 2007 Honestly a bone stock th350 in good shape would handle that combo without breaking a sweat!! I have run th350's with mods including a 34 element sprag with 2X's that HP at the rear wheels! I have stated before on this board, B&M is not high end top notch stuff anymore. In the 60's and 70's it was the best around and they still build them the same way now as they did 30 or 40 years ago!! No thats not a GOOD thing! Back then a blown BB was set of kill with 500/550hp!!! A nitro burning top fueler was kicking out 1000hp on 90% pop(nitro) and 30#'s of boost from an 8-71 roots blower. I have never had any luck with anything other than B&M's shift kit's. Every trans or converter I have seen installed behind one of my engines died rather quickly! Don Quote Link to comment Share on other sites More sharing options...
Cali4nia Monte Posted March 21, 2007 Author Share Posted March 21, 2007 Thanks Don, Its completely ridiculous, I mean the motor is a nice starter for us, but Mike already wants to go bigger. Well he actually wanted to go bigger from the get go but what we got fit our budget... We are going to have the the transmission shop beef up the B & M, well rebuild if they screw us over or just beef it up if they do end up giving us tranny #3. Its just depressing that we spent $1000 on the darn thing only to have all these hassles and now were going to have to fork more to get it done right! I mean the first transmission Mike put in was defective right out of the box! He never even left our neighborhood before he turned around and came back saying that it would not shift out of first. The second one he got to enjoy a few good romps around town before it started acting weird, weve looked in all the paperwork and on B & M website and nowhere does it state that their TH350's are only rated to 325 HP. Plus they are saying that if we return it and "they" determine that it was not their fault it broke they are going to charge us $270 for them to look at it. Quote Link to comment Share on other sites More sharing options...
680HPStroker Posted March 21, 2007 Share Posted March 21, 2007 Welcome to the down falls of mail ordering parts. I used to do a lot of mail ordering, but had similar issues with failed/wrong parts. I now only mail order small accessory parts. My advice is to find and stick with a local parts store, machine shop, and tranny shop that is well respected for standing behind anything they sell/build. Since I've started doing that I have a lot less stress. Just my two cents. Quote Link to comment Share on other sites More sharing options...
Cali4nia Monte Posted March 21, 2007 Author Share Posted March 21, 2007 No we didn't mail order it...we purchased it from a well known local speed shop here in Riverside. They were very helpful with the first tranny and would have just exchanged it but did not have another one in their shop. We talked to their rep from B & M, and Mike actually wanted me to drive straight to B & M because its only about an hour from us, but B & M said they also didn't have one they could just exchange for me...so we had to wait almost 2 weeks for them to "build" one just for us, because as they put it all of their stock was already spoken for. The local speedshop is again helping us with this situation and they are urging us to make B & M make it right because Mike is ready to just eat it and have the tranny rebuilt by Lukes (the tranny shop) Lukes said they could fix it and beef it up for I think around $400-$500. But Mike figures if B & M determines that they are not at fault...as it sounds like they are trying to do by saying our motor has too much HP and they charge us $270 then its really going to cost us even more. So the tranny is back out of the car and waiting to go back to B & M...and I we will have to see who's going to eat it in the end. Jaylene Quote Link to comment Share on other sites More sharing options...
502ci Posted March 21, 2007 Share Posted March 21, 2007 My advice is to find and stick with a local parts store, machine shop, and tranny shop that is well respected for standing behind anything they sell/build. I purchased a tranny (mail order) that was "supposedly" built with the best of parts. It failed 30 days after the warranty expired...I had inflicted no abuse on the tranny (no sticky tire launches) but normal driving, later found to be not built to my specs. I took it to a local tranny shop (Cottman Transmission) and to visibly see the enthusiasm in the guy who would be rebuilding my tranny was reassuring. I have since beat the daylights out of the tranny and it is holding strong. I agree find a local speed shop or equal to build such parts... Quote Link to comment Share on other sites More sharing options...
502ci Posted March 21, 2007 Share Posted March 21, 2007 I see you reponded ahead of me and said that you did purchase it locally... Quote Link to comment Share on other sites More sharing options...
Cali4nia Monte Posted March 21, 2007 Author Share Posted March 21, 2007 Yeah idealy we would have just had the stock transmission built and beefed up, but when we first pulled it from the car we discovered that the bell housing had a big crack in it. So we didn't think it would worth messing with. Mike has probably driven that old tranny harder then either of these new ones just because he didnt care about it...LOL Quote Link to comment Share on other sites More sharing options...
680HPStroker Posted March 21, 2007 Share Posted March 21, 2007 I know we are splitting hairs here, but if it was ordered by anybody as complete tranny it was still mail order. I hope in the end that you get a reliable tranny that you can feel confident in when you beat the snot out of it. Quote Link to comment Share on other sites More sharing options...
Heckeng Posted March 21, 2007 Share Posted March 21, 2007 Regardless of the mail order issue, they paid $1000 for a transmission from a large name company that had a decent reputation. It should work, the first one should have worked for that matter. As long as it is nothing that you have like it cooking itself because of too tall of gears with a high stall converter or something like that, it should be a done deal. If this proves to be non-user error and B&M doesn't step up, I will never buy another item from them again, including their shift kits which have worked well for me in the past. I won't support that kind of business. If on the other hand, it is user error, that's not good and B&M should get the credit for not producing a bad product. Jaylene, try to find out your rear end gear ratio. If you are running a 3000rpm stall with 2.73 gears, that can generate LOTS of heat and cook your transmission. Hopefully you have 3.31 to 3.73 or so. You would definitely want to find out what part broke etc when it is disassembled as well. It sounds like your clutch packs are not being fully applied, which could mean a warped or leaky valve body, or low fluid pressure from the pump which could be a pump issue or a spring problem in the pump. I'm not a transmission guru, so I'm not 100%, but I'm sure we have some transmission guys on the forum that will chime in! Quote Link to comment Share on other sites More sharing options...
Cali4nia Monte Posted March 21, 2007 Author Share Posted March 21, 2007 try to find out your rear end gear ratio. If you are running a 3000rpm stall with 2.73 gears, that can generate LOTS of heat and cook your transmission. I will definitely let you guys know...Mikes not here to ask about the gears, but I do know that he installed a "trans cooler" when we purchased the first transmission. I believe this was done at the suggestion of the speedshop, although I don't remember why. I always ask....why, why, why when he is spending the $$ and if its like you said that the gear ratio and the 3000 torque converter combo ends up being the problem then I think we need to be ticked at the speed shop as it was at their suggestion we went with the 3000 vs the 2500. I mean Mike has been down there every week since we first bought the car in August, they know where we started and they know what weve done and they are supposed to be the experts. I know for a fact that he has discussed the rear end with them because they gave him the name of a place to go to because he wants a posi rear end?? Am I on the same page or am I talking about completely different gears? Anyhow I will let you know...the good bad or ugly truth. Jaylene Quote Link to comment Share on other sites More sharing options...
Heckeng Posted March 21, 2007 Share Posted March 21, 2007 That is excellent that he had the transmission cooler put on, that will definitely help. In general, the higher the stall the more heat it will produce when not operating above that stall speed. If you have really high gears (highway type gears), your rpms will tend to stay low, which can keep the cruising rpms below the rated stall speed, and the converter is inefficient at those speeds and creates lots of heat. Hopefully this is not the issue at all, and B&M just gave you guys some bad parts. Quote Link to comment Share on other sites More sharing options...
Cali4nia Monte Posted March 21, 2007 Author Share Posted March 21, 2007 Ok well I just heard from Mike, B & M has confirmed what the transmission shop said in the first place...its a broken sprag. B & M is saying that our 377 hp motor is the reason this part broke, according to them its too much horsepower for their TH350, they didn't say anything about it being gears or appearing to be overheated, their saying its just too much HP! The speedshop (which I keep calling "speedshop" because its called J & M Speedcenter and felt it would be confusing) is going to upgrade/give us a B & M TH400 they have in stock, they said its BS what B & M is pulling and they will deal with it. The only bummer is that we have to now have the driveline cut down and are going to lose some of that 377HP, Mike is sick of pulling trannys so we are just paying Lukes to do all of this work. So there it is..... Jaylene Quote Link to comment Share on other sites More sharing options...
buster Posted March 21, 2007 Share Posted March 21, 2007 I ran a 350 turbo behind my LS7 for 4 years and that trany is in my 57 bel air today and working strong!(I ain't easy on parts nither ) May be a fluke or just a darn good trany but I figure shoving 500+ hp down its throat is a good test for a 350 th ..I did have a B&M shift kit in it with ford type F trany fluid if that makes any difference. http://s129.photobucket.com/albums/p218/bust-er/?action=view¤t=tuningthels7atthetrack.flv terry Quote Link to comment Share on other sites More sharing options...
502ci Posted March 21, 2007 Share Posted March 21, 2007 Well that is sad B&M is sticking to that story cuz no way would 377 flywheel hp destroy that tranny... Quote Link to comment Share on other sites More sharing options...
kc8oye Posted March 21, 2007 Share Posted March 21, 2007 i agree.. th350's are tough monsters.. usually what breaks the 2nd gear sprag is nuetral slams or reverse-hole-shots :> the TH350 in my monte .. when I got it "ran" i use quotes.. cuz when I got it open.. the clutches were GONE.. it was just steel-on-steel.. but according to the guy I got it from.. it drove ok "it just slips a little bit" heh.. Quote Link to comment Share on other sites More sharing options...
Cali4nia Monte Posted March 22, 2007 Author Share Posted March 22, 2007 I need to clear up some of my facts...I originally talked to Mike on a cell and it was hard to hear him. I guess B & M was not totally trying to get out of the warranty on the transmission, they just wanted us to pay them to upgrade the 2nd gear sprag to a heavier duty one and beef up something else as well. The speedshop did not want us to have to wait another two weeks like we had to with the first transmission, so they gave us the TH400 they had on their shelf. Besides the fact they know Mike wants to get a BB as soon as we win the lottery.... Oh yeah and Mike said there was no neutral drops or reverse hole shots involved in the demise of this tranny. He said he had stepped on it to get on the freeway and it just made this weird noise ...its kind of hard to explain when you cant hear my sound effects... But he said he never heard anything pop or anything like that it just sounded like it slipped out of gear. Quote Link to comment Share on other sites More sharing options...
Guest Posted March 22, 2007 Share Posted March 22, 2007 TH350's and 400's do have a problem with the sprag at times. Mostly caused by improper burnouts. To take the load off the sprag only spin the tires to about 3000/3500 rpms in low gear shift to second then ease into the throttle to bring the rpms up. As for the 377hp breaking the sprag under normal driving PURE AND SIMPLE B.S.!!!!! 325hp is way lower than the 450hp claimed by GM when they built it new. B&M must really use some cheap over seas junk parts to actually lower its rateing from stock. Don Quote Link to comment Share on other sites More sharing options...
wallaby Posted March 22, 2007 Share Posted March 22, 2007 It sounds as if things are finally turning out as they should. I don't know how you got in the middle of this; it should have been an issue between your speed shop and their supplier (B&M). I'm glad to see that the speedshop is willing to do what's right and settle it with B&M without getting you involved. That's how it should have been done in the first place. It shouldn't matter whether it's a water pump or an automatic transmission; if you buy it and it doesn't work they should give you another one. If the supplier can't provide a decent product, the distributor is the one that should take the hit, not the customer. It really makes me mad when they tell you that you're at fault for buying their product. The way B&M is treating the issue, I wouldn't be surprised if your speed shop stops selling their transmissions. That's good for everyone except B&M. Quote Link to comment Share on other sites More sharing options...
gprimm Posted March 23, 2007 Share Posted March 23, 2007 A TH350 has been used behind a 383 stroker in a 1988 Monte SS that runs in the low 12's for 3 years with no problems. A friend who is the national sales manager for a national driveline / rear end company has an opinion on this. He suggests avoiding B&M as they are getting cheaper as parts from the Orient. He uses TCI behind his LS-2 1971 Chevelle EATON SEMA car(as seen in Super Chevy and Car Craft). An experienced trans builder around here won't touch a B&M convertor. George Quote Link to comment Share on other sites More sharing options...
Grease Posted March 23, 2007 Share Posted March 23, 2007 I dont recall you noting the rear axle ratio. You should know that the first gear ratio in a T400 is a higher ratio than first gear in the T350. With your higher performance s/b it may not be a problem . But the way the car will run with a T400 could be quite differnt from how it felt with the T350. I just want you to realize this possibility.It may require a lower rear axle ratio to get the performance back. Been there done that in my first 70Monte.350hp s/b with trans upgraded to T400, still had the stocker 2.73:1 axle ratio. It wasnt near as fun to drive that way . I sold the car before I realized my tranny upgrade was the cause of the problem. Quote Link to comment Share on other sites More sharing options...
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