Building a th-350

[Stomper]

First, if you don't like auto's, that's fine...But I don't want a stick, so, with that out of the way.....

I'll be rebuilding my th350 here in the next week or two and I'd like some input on what kind/brand of rebuild kit to use. What internal beefy goodies should I consider along with the rebuild? I'd like to do it correct the first time around. Also, I'd like to get the opinions of what has worked best for you, not what some one is trying to sell me.

I've been looking around places like TCI and Art Carr but there descriptions of there rebuild kits leave alot to be desired.



Specs.
4bt
th350
doubler type kit,203/205
4.10 gears
42's




Here is what I've got so far.

TCI GM TH-350, all non lock-up, reverse shift pattern valve body 321115 4 .... 4 Retains 1st and 2nd gear engine braking

B&M Cooler 11"x11" stacked plate... can't remember the p.n.

Deep finned aluminum pan.

Thanks,
Brett

 

[sweetk30]

hay my name is brett also cool.

all my friends have had great luck with (transstar) kits in there big mud trucks and some of them were over 6000 lbs. with bbc in frt of them and th350 trannys. this kit is the best bang for the buck in there book. and get the case saver also at any tranny shop. get the 1 that looks like the state of texas NOT the 4 piece kit thay are a bi$$h to install them. get the big cluch packs and keep her cool. i had the same th350 with these parts in my last truck and it had 400 sbc built and in lb truck 6300lbs 1ton axles and no problems. happy building.

 

[Beast388]

When I built my TH350, I purchased the rebuild and band from Napa and a TCI Transcat Super II shift kit from Jegs. I also borrowed the Haynes manual for GM trannies which was a huge help. That book had tons of pictures and excellent instructions.

I just took my time, followed the instructions and put it all together. It has been shifting flawlwssly for 5 years since.

 

[mouse]

Do a detailed step-by-step, with pics, and post it here. I'm sure it would last for decades...I would read it intently

 

[odoa3]

I second the step by step write up. I need to rebuild mine as well!

 

[Ryan B.]

I rebuilt my th350. I went with the B&M master racing overhaul kit for about $125. comes with the clutches, steels, bands, bushings, seals, and gaskets... only thing it doesnt' come with is the 4 thrust washers in the tranny, two of them adjust the endplay of the input and output shaft.
You'll need to measure that endplay before you tear it apart.
Also make sure you put on the front oil pump gasket the correct way, it is possible to put it on backwards so all the holes line up except for the vent tube hole... Then the tranny won't vent and will puke ATF out of the dipstick, catching your truck on fire. Ask me how i know on that one.
I also put in a B&M stage 2 shift kit at the same time, and it barks the tires shifting into 2nd a lot. very fast snappy shifts.
Got about 3-4 years on this tranny.

 

[sweetk30]

when the case is completly striped and ready for cleaning take the vent out of the case and tape the hole with a 1/8 pipe thread tap and clean out the hole and install a barbed end in the hole so you can run a hole up by the firewall if you play in the mud and h20. this will get the vent up top away from h20.

 

[AkMudr]

I noticed you got a cooler and deep pan, good call..will definately xtend the life of the tranny.

 

[Greg72]

I was going to say "tranny cooler"....but I see that's already on your list.

With an aluminum pan, may I suggest a skidplate of some sort?...Aluminum is nice, but it doesn't "play well" with rocks... no second chances, if you hit it...odds are you're walking home.


Beyond that I can only say that the combination of 4.10s and 42's is probably going to make you miserable, at least around town. I'm running a 396/TH350/205 combo with 38.5s and 4.10 gears. The truck just doesn't want to stand up and salute off the line..... it g-o-e-s....but it's not exciting, and I'm sure that the tranny is working pretty hard to get all that mass rolling, especially without much help from gearing. My highway RPMs are great (your's will be even better) I think I turn around 2500RPM at 65 so there are no complaints there.....

My tranny runs cool. I have the biggest (28,000Lb? B&M) cooler on it so I'm doing everything I can to be "nice"...I've run this TH350 for a few years now and so far it's treated me well. My next truck is getting a TH400 but only because I'm planning to have a little more "heat" in the engine department.

 

[Stomper]

and get the case saver also at any tranny shop. get the 1 that looks like the state of texas NOT the 4 piece kit thay are a bi$$h to install them.

You wouldn't have a link or a picture to this? I searched last night but didn't come up with anything.thx Transstar is now bookmarked.

I also borrowed the Haynes manual for GM trannies which was a huge help. That book had tons of pictures and excellent instructions.

I've got a big manual from when I went to auto/diesel tech, so I hope it has enough info. thx

Then the tranny won't vent and will puke ATF out of the dipstick, catching your truck on fire. Ask me how i know on that one.

Note to self: FIRE BAAAAAAAAAD

when the case is completly striped and ready for cleaning take the vent out of the case and tape the hole with a 1/8 pipe thread tap and clean out the hole and install a barbed end in the hole so you can run a hole up by the firewall if you play in the mud and h20. this will get the vent up top away from h20.

Good idea. thx

With an aluminum pan, may I suggest a skidplate of some sort?...Aluminum is nice, but it doesn't "play well" with rocks... no second chances, if you hit it...odds are you're walking home.

I've got a flat belly pan built for the tcase area, I'll look into extending it forward some more.

Beyond that I can only say that the combination of 4.10s and 42's is probably going to make you miserable, at least around town. I'm running a 396/TH350/205 combo with 38.5s and 4.10 gears. The truck just doesn't want to stand up and salute off the line..... it g-o-e-s....but it's not exciting, and I'm sure that the tranny is working pretty hard to get all that mass rolling, especially without much help from gearing. My highway RPMs are great (your's will be even better) I think I turn around 2500RPM at 65 so there are no complaints there.....

Yep, with a massive 105 hp I'm pretty sure it's going to be a dog on the street. The 4.10's were in the axles, so for now it is just a test to see how much of a dog it is. Regearing is definently an option for the future.

With my limited RPM range I can only go so deep in the gears and still be able to drive it on the street. Just from memory, with 5.13's I believe my top speed would be 45mph, that is also not very street friendly but a complete 180

Also, I forgot to mention that I do have a temp guage.

Thanks for all the reply's!! Anyone else?

 

[AkMudr]

If yer after some beefy internal parts...

www.coanracing.com

 

[miniwally]

TCI reverse manual Valve body is the Cats A$$.
Order a larger cooler/ get the biggest oe you can find. I don't think you will be happy with that 11X11

I put a Cooler/Fan combo on my buggy that is a little bigger than that and it works great for low speed stuff but the tranny will get to about 210 when I haul a$$ for about an hour.

The TCI vavle body boosts line presure to full line pressure on all shifts all of the time. I don't see a need to put in a "shift kit" I would install the best clutches that you can though.
You just may be a good canidate for the lower first gear option as well. It is expensive and does not get you that much lower gear but it will help.
BTW 42" tires,4.10s and TH350 are pretty hard to get started moving.

 

[Greg72]

TCI reverse manual Valve body is the Cats A$$.

Is this a bolt-on affair...? How "deep" into the tranny do you have to go to install something like that....?

Everything I know about the inner workings of an autotrans would just about fill-up a thimble... Isn't the valve body that external round cover on the side of the trans case??

 

[AkMudr]

TCI reverse manual Valve body is the Cats A$$.
Order a larger cooler/ get the biggest oe you can find. I don't think you will be happy with that 11X11

Wanna give us a quick run down on valve bodies, the different types and what they do?

With a full manual I know you hafta up/downshift 1005 of the time but whats the difference between full manual and full manual reverse?

 

[miniwally]

Reverse pattern VB gears lay out as follows P R N 1 2 3
Regular shift pattern is P R N 3 2 1

For crawling it works nicely having 1st and reverse only seperated by Neutral.

Make damn sure though that you get the VB with Compression braking.

 

[Beast388]

Is this a bolt-on affair...? How "deep" into the tranny do you have to go to install something like that....?

To get to the valve body, just remove the tranny pan and you are looking at it. The valve body just bolts to the case itself. It is really the "brains" of the tranny. When you install a shift kit, the majority of the mods are done to the valve body.

Isn't the valve body that external round cover on the side of the trans case??

Uh...no. That would be the cover for the governor assembly.

 

[Greg72]

To get to the valve body, just remove the tranny pan and you are looking at it. The valve body just bolts to the case itself. It is really the "brains" of the tranny. When you install a shift kit, the majority of the mods are done to the valve body.



Uh...no. That would be the cover for the governor assembly.

.....blush...... make that a SMALL thimble.

 

[Beast388]

.....blush...... make that a SMALL thimble.

Well, now thanks to CK5, that thimble is a bit bigger.

 

[Stomper]

TCI reverse manual Valve body is the Cats A$$.
Order a larger cooler/ get the biggest oe you can find. I don't think you will be happy with that 11X11

I put a Cooler/Fan combo on my buggy that is a little bigger than that and it works great for low speed stuff but the tranny will get to about 210 when I haul a$$ for about an hour.

The TCI vavle body boosts line presure to full line pressure on all shifts all of the time. I don't see a need to put in a "shift kit" I would install the best clutches that you can though.
You just may be a good canidate for the lower first gear option as well. It is expensive and does not get you that much lower gear but it will help.
BTW 42" tires,4.10s and TH350 are pretty hard to get started moving.

You were one of many reasons that I picked that Valve body.

As for the cooler, it is the biggest that B&M makes I believe at 29,000 plus. I'll look into a dedicated fan tho. Thanks,

 

[sweetk30]

to help get the truck rolling and if you have some extra bucks to spend get the extra deep 1st and 2nd gear set up from a tranny parts shop. this will lower 1 and 2 gears to help take off. my friend had them in his old sbc powerd 383 toyota truck and that thing would about rip the back shackles off the frame. and it might help you in cralling. just a idea. and your 3rd gear will stay the same.

iwent and looked at the link that akmard posted and thay have them for 483.00 and its all there 1st gear is now 2.70 and second gear is now 1.52 thats deep for what i want . and sounds good on price also. its in components then th350 section and then 3/4 to bottom ( planetaries/kits)