Sorry to side track, albeit a bit brief, but I'd like to add that the 2004r trans coupled with a 3.73 gear is probably one of the most ideal/nearly perfect combination for a street/strip combination ranging from stock to moderate. Final drive ratio is 2.499 (kinda in-between a 2.56 and 2.41) which is really all anyone would need for interstate driving (using this combination of gearing). :TU: Edit: HA first on page 13! :grin: Gary
It was the best upgrade I ever made to the car. 410 gear I think is my next move to go with the SP3. Might as well throw in a roller cam too.
HAHAHA, I don't know where the rpm drops back too after the 1/2 2/3 shift, I didn't know my trans. was crap, who knows for how long tooo No: Guess I'll have to start ALL over in the spring with my fresh trans, who knows, maybe my 13.65 @ 98 mph wasn't my best with the DP, maybe I coulda got close to the 12's or way low 13's, DAMN maybe put the Stage 1 on and start fresh
Mark, are you going with a rebuild of yours or are you looking to buy one from a tranny company? I'm in the same boat. My tranny guy told me he thinks that a 2.75 first gear (200r4 gear?) is available for the TH350. I'm waiting to see if that is fact or fiction. Tony
What makes you so sure the trans is toast. When you put in the torque convertor did you pull it back out from the trans at about .080 thous for the proper end play? If the tq convertor stays against the pump in the trans it will burn it up. If pulled too far out same thing will happen by losing contact. You shim between the flex plate and the torque convertor to get the proper .080. In other words push all the way in and put enough shim in to get to .080 and pull it out that much.
Mark, I'd say that your trans(if in reality it is bad) probably started going around the day you were running your fastest times so I wouldn't get too excited. You have to wonder if the newer high stall converter didn't just push it over the edge by applying more torque to the clutches and with how many runs on them since the 90's maybe that's all they needed. One factor for sticking with a T350 is the rebuild price should be noticeably cheaper than a 200-4R rebuilt to take the same amount of HP the T350 can and even more so if you have to buy a core. Converting a T350 converter to a 200-4R would be prohibitively expensive because IIRC the hub and input shaft are larger on the T350. At that point you may as well sell the converter and buy a new 200-4R unit. Along the same lines a 2.75 gear set for a T-350 are going for around 500 plus installation and a trans shop would probably want to supply it and mark it up. Your good converter will all but make up for the difference in gearing for off the line performance. A lower stall converter could probably use the extra grunt off the line but don't forget that the 200 probably weighs a bit more than the 350. Don't even get me going on working on that 200-4R governor, hoo boy! Been there done that. http://www.summitracing.com/parts/ati-354040/overview/ The big question you have to ask yourself as far as converting to a 200-4R is how many miles are you going to put on the car that the OD is really necessary. For an occasional cruise down the highway or trip to the track IMO it is not worth it. If you plan on at least a few thousand highway miles a year it could be. In that case the real value is in its ability to cut down on wear and tear to a HP engine over many miles. The higher MPG is just a bonus. One plus it does have is the lockup converter but if you don't lock it up going down the strip you're leaving performance on the table. All the GN's with LU do. As far as too much or not enough converter engagement goes not enough and as soon as it disengages the car will stop moving. Too much engagement where it bottoms out on the pump occasionally while driving the pump could certainly be damaged causing possible low pressure and clutch slippage but engagement can't be too bad because if the pump was really ruined the car would stop moving once it goes plus making all kind of whining noises leading up to it. I would check your converter play for sure before you pull it just to see what it is.
Hey Mike, You touched on everything I've been pondering about the 350 verses 2004R swap since its been mentioned. I like the overdrive idea, heck my GN has the 2004R, and it holds up well (no track time yet tho) but to bring the 2004R strength up to the T-350 is going to cost more. Im sticking with my T-350. If Im capable of going 13.5 or finally hit 100 mph in the 1/4 I'd be happy. If I MAGICALLY do a 12.99 I'd be real happyp
Im having mine rebuilt. I wasn't aware of a first gear swap ( Im not trans. savvy) was available for the 350 trans. But as Mike mentioned its not a huge difference in ratio. If you were going from the stock 2.52 first to a 3.52 first, then it would make a difference I would think. Im putting my money into stronger parts where needed instead.
A modified 700r first gear is all that's needed to get a low first gear in a th350 thats tranny building 101. Janis will know the routine im sure But its usually a $75 /$100 upgrade. The stock hard parts are fine for your application I promise, I ran th350s for years in high 11sec 4000lb cars with 60's in the 1.6's.
I pulled the engine to put the convertor in, I installed the convertor two or three times to make sure it went on two clicks/thumps. There was the required clearance between the flexplate and convertor, THAT I made sure of:TU: Last night I went under the car and noticed my detent cable casing was pulled out of its plastic "boss" that bolts to the trans. case. The cable eyelet itself was still connected to the small wire that protrudes from the trans. Not sure if that would make a difference being the cable itself is still attached, but thinking as the engine torques to the right, the trans case goes lower on that side maybe pulling the casing outo No: Another thought, the trans "seemed" fine before the drag radials. Maybe the traction from the DR's pushed the trans over the edge................ next weakest link. When I changed the filter and fluid a few months back, there was quite a bit of fiber (clutch) in the pan, I didn't give it a second thought as its was the first filter and fluid change since the rebuild in the 90's, it only had around 14000 mi. on it
The points brought up before make a lot of sense. If this is more a strip car than a cruiser stick with the t350. It would be a lot of headache dialing in a new carb and a new transmission at the same time. The t350 is a proven unit, cheap to build and will get you what you want. Also, if it turns out your Trans did have a failure of some sort, or even if it didn't, flush that converter. Either talk to who you bought it from or the place rebuilding your trans. It's worth the extra money knowing you aren't running contaminated fluid through your brand new transmission. Also do a thorough flush of the trans cooler if you have one and the radiator trans cooler if you use it.
Good to know Hugger, thanks! Like I said Im not trans. savy Now the 700R4 trans first gear would be worth doing in my opinion a 3.08 vs a 2.52:Brow:
im not certain if it will be 3.08 im thinking its 2.75 as they only use one side of the gear set or somthin another I just knowmy trans guy turns them on a lathe for reason or another and you get a lower first gear it will help with the 60ft but its also gonna put you in 2nd faster and at a lower mph which may hurt you its a trade off I rekon.
Not unless 2nd gear can be changed as well because the drop off from 1st to 2nd would be even worse than what the 700R4 is going from a 3.06:1 to a 1.63:1 gear ratio for 2nd gear. With the 3.06:1 in a TH350 and 2nd gear unchaged at 1.52:1 the RPM would be taken WAY to low without over revving the flock out of the engine and absolutely kill your QM times, that would be over a 50% drop in gear ratio going to 2nd gear!! If you could get traction with the 3.42 rear gear and the 3.06 1st gear your 60 ft times would be great, but when you hit 2nd gear @ 6,000 in theory the RPM would drop to 3,000 with the torque converter raising that only slightly. With the SP3 your max torque probably isn't until 4,000 plus RPM now and that is where you would want your RPM to drop to when you shift, no lower to be able to stay in that sweet spot. That is why the TH350 works so well because of how the gear ratios are spaced out to keep the engine in the sweet spot when it shifts. Derek
I agree with both Hugger & Derek on both the traction issue and the big drop off in rpm on the 1-2 shift. You'll definitely drop ell under 4500 on the1-2 shift.
I can hear Janis asking you right now what the heck you want to do that for. The extra cost might as well go into a 2004r trans. You are told not to do anything now you want to change the trans into something else, I swear. A direct bolt in and the car will run the same and the times will not change in fact it will probably go faster if you keep the same stall. I went from a 3500 loose stall to a tight 3000 stall and ran the exact same times. Does anyone ever listen to someone that has been there done that or is everyone on some other cloud.
Better watch that kind of talk you're starting to sound like gsjohnny. Besides once Mark found out it would cost around $750 just for the 2.75:1 first gear set for a TH350 I'm sure he would scrap that idea. A bench job to throw some new clutches in his trans won't hurt his wallet as bad as buying a whole new trans. You can tell someone until you're blue in the face how to spend their $$ but you can't take it personal when they don't take your advise. Derek
Hey there Mr. happy, I started the question about the 2.75 first gear not Mark. Please read back few posts. I am a great listener, please do tell the difference between the 2.52 to the 2.75 first gear. Tony
The difference is right around 8.4%. With a 9.5:1 first gear multiplication ratio being optimum for a street/strip car that ratio with the 3.42 rear gear in the car now will bring it to 9.405:1 1st gear multiplication ratio from 8.6184:1 1st gear multiplication ratio with the 2.52:1 first gear ratio. If Mark had a 3.73:1 rear gear ratio with the TH350 his FGMR would be 9.3996:1 optimizing his 1st gear ratio that will be helpful to recover RPM when shifting. With the 2.75 1st gear the drop off from 1st to 2nd would probably make it a wash from the potential gain off the line the extra gearing in low 1 would give the car vs. the setup in there now. Derek
