Order Sheet Tranny Question

[HotRodPC]

Thanks... we seriously haven't had a lick of trouble with that tranny in the 22 years we've had the truck, until just a few weeks ago when it just stopped working altogether.

The tranny itself had to have at least 400k miles on her... so not a bad haul.

The dude that re-build my tranny said it was good and worn through. We took it as far as she would go, and then some!

You can get that kind of mileage out of a Th350 but you'd never get it with a 700r4. Also when it comes time for the rebuild, you'll be glad you have the Th350. To have the 700r4 built, is about double what it cost to have a Th350 built and the converters replaced. The later 700r4's aren't so bad with some aftermarket updates, but they'd still never stand up to the durability of a Th350 or Th400. For a half ton pick up, unless a big block, Th400 is just overkill and you do suffer from that overkill in strength. 3/4 ton up, I'd say the Th400 is justified.

 

[CaliDude76]

You can get that kind of mileage out of a Th350 but you'd never get it with a 700r4. Also when it comes time for the rebuild, you'll be glad you have the Th350. To have the 700r4 built, is about double what it cost to have a Th350 built and the converters replaced. The later 700r4's aren't so bad with some aftermarket updates, but they'd still never stand up to the durability of a Th350 or Th400. For a half ton pick up, unless a big block, Th400 is just overkill and you do suffer from that overkill in strength. 3/4 ton up, I'd say the Th400 is justified.

Definately! I've always heard good things about the durability, and universal applications for th350's, (great for jeeps and such). I have first hand testimony on the strength of these tranny's. Glad to have it re-built, and it lasting me another 400k.. my future children's children will still be enjoying the truck.

 

[bucket]

Maybe mine is a th350 then, I dunno. The pan looks a little odd to me. It can't be a 350c can it? The truck has Cali emissions and no ECM because of it (yeah, kinda weird).

...I guess I should just crawl under there and get a good look at it.

 

[Swims350]

it DEFINATELY could be a 350c, just look for the plugin on the DS behind the shift linkage dead give away to a 350c. a 350 pan is square just one corner knocked off at a 45 degree angle. same as the 350c

 

[HotRodPC]

Yep, 350 and 350C pans are even the same. The plug in on the DS as swims pointed out, and of course output shaft is a dead giveaway too but you can't see that while installed in the truck. Now you could pull the torque converter cover and tell if its got the non clutch or the clutch type conveter and that will tell you too if its Th350 or Th350C. If its mid 80's and not a 700r4, then its at least a Th350C lockup if original since by 81 all Th350 were lock up Th350C.

 

[bucket]

What ran the lockup if there's no ECM? Is that what one of those vacuum switches on the firewall are for?

 

[RetroC10Sport]

Yep.

 

[HotRodPC]

What ran the lockup if there's no ECM? Is that what one of those vacuum switches on the firewall are for?

You Guessed it. Vac switch with trans in top gear locks the converter, either brake light or I think its 8hg drop in vacuum, the lock up unlocks, then it takes the same requirments to get it to relock again.

 

[HotRodPC]

While on the subject, there is the difference in input shafts of the Th350 and Th350C.


NON LOCK UP

LOCK UP

 

[dhamp]

I'd have to check and make sure, but on the 8.5 inch 10 bolt, I do beleive the 2.73 and up numerically use the same carrier.

If you have 12 bolt, then is 3.73 and up numerically meaning lower gear. So 3.73 carrier should work for 4.11 and 4.56 etc. Then the 3.42 and down to 2.73.

If your not wanting to change gear and just go with a locker, go with Richmond Powertrax Lock Right unit. Its just a spider gear replacement system. Take out the spiders and install this unit, now you'd have a locker and that will work on any gear ratios. Only thing you need to know for sure is what your spline count is on your axles so you can get the right outer gears.

Yeah, it's the 8.5" 10-bolt. I do have future plans to go with the Powertrax, but I'd also like to step up to some 3.42s at the same time. Maybe CaliDude will do it first, then I can learn from his thread!! LOL

 

[89Suburban]