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TH350


Lou

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Next on the inspection and repair list will be the TH350.

FYI, I'm a manual guy so go easy on me.

When I start from a dead stop the car gradually increase in speed. when 2nd and 3rd kick in you can feel it good. Before going the rebuild route, I'd like to know if there's anything to check without pulling the tranny in order to eliminate it. The guy I bought it from told me before I even test drove it that he had the tranny rebuild and checked for the same issue and that "It's not the transmission".

I know it's not the brakes dragging or the tranny fluid level.

What else can I check? Modulator? vacuum lines?

What would cause the issue?

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What are you asking? Shifting firm 1-2 and 2-3? Gradual take off from stop? 

What does being a "manual" guy mean? You never drive automatics? You have only rebuilt manuals? 

Not trying to be a wise [censored], just trying to clarify to best answer you. 

Gradual increase in speed is akin to slipping the clutch. Firm shifts, like letting up the clutch pedal very aggressive into each gear. 

What is the stall speed of the converter? Rear gear ratio? 

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Manual transmission guy.

And yes, I only have an issue from a dead stop. I need to build rpms to get moving. I can mash the peddle in 2nd and will drop down to 1st normally. It's just an issue from a dead stop.

Stock converter, 3:08 posi, 225/70/R15.

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Sure the converter is stock stall speed? What's done to the engine? 

As of right now, from what you are describing, sounds like a higher stall converter and 3.08 gear combo. That the converter has to overcome the highway gear ratio and the weight of the car. Excess slippage.  

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That's actually good news. I planned on changing the gears to 3:55 or 3:73.

The car is drivable as it is but as far as launch, forget it.

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10 or 12 bolt rear? Plans for the car? 3.55 is a nice highway gear. The 3.73 is kinda the edge for some. Especially with the 3spd th350 or 400. But the 3.73 will get you out of the hole faster. The new issue would then be traction. The 225s will be angry. Lol

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10 bolt. Plans are a pleasant weather weekend street/parkway cruiser. Plus local shows.

My last Chevelle had 3:73's, my current daily 96 Silverado has 3:55's, my 90 silverado which I still have has 3:73's. But the trucks have OD tranny's.

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I've heard that the TH350/200 4R is a straight up swap beside the TV cable setting and pressure checks required for the OD. I'll end up doing something like that or even better and way more bullet proof, stick with the TH350 and add a Gear Venders OD to it. I think the 350 is original to the car so there's that consideration also. Haven't gotten into it yet.

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I did the 200r4 swap. The biggest issues were the clearances around the tail end of the transmission, (depending on which driveshaft you have.) the length of the driveshaft, moving the cross member back, getting the right linkages and getting them set right. (t.v. cable)

But for a cruiser/highway driver, I really like the results.

Just keep this in mind, get the 200r4 rebuilt..... and make sure they use a hardened barrel/input. Otherwise any hard torquing will tear the internals apart. 

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Yeah Scott, that's what I'm talking about with the 200-4R or the 700-R4 (which I already have). It may be better and more cost efficient to just go with the Gear Vendors OD which bolts onto the existing th350.

But, haven't gotten that far yet. Just forward planning at this point/talking to people for info.

The first thing I'll do is find a stock console and horseshoe shifter to put in in place of the one that's there now which is a mid-seventies something. So, my considerations now have a lot to do with what I end up with.

My son already told me when he gets the car he's putting a manual in it anyway.

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Hey Lou,

I found that the 200r4 is the straight bolt in. The 700r4 requires to many modifications to install. (cross member, yoke, and maybe some trans tunnel issues)

As for the bolt on O.D., I never really looked into it. But I would imagine it's fairly simple.... a couple brackets, some type of shifting arrangement, and shortening the driveshaft would be my guess. 

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its rolling. was a little tough to put in. had to section apiece of floor for clearance gear vendors said clearance problem might be from original body mounts. measured drive shaft length wrong had to have new shaft made. have a vibration need to check drive line angles starting with balancer on engine, back of o/d unit,  drive shaft , pinion yoke and figure out how much height difference between front to rear

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Hmm, sounds fun. 

I don't want to be cutting up original sheet metal.

So, maybe I'll just stay off the highway and stick with the stock trans and a 3:73. Yeah, that's the plan.

Like I said when my son gets it, he can put in his manual.

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