New here from MS K5 Blazer

[Old77]

Wow! 3k for a rebuild or was it a brand new, beefed up tranny? That seems high to me unless there was an awful lot of goodies that got thrown into it.

 

[HotRodPC]

Yep, I'd have to say everything was done and maybe even more, like the hardened input shaft. That alone can be close to $1000 part. So you sure shouldn't be breaking that one.

 

[Old77]

$1000 just for the part? Wow! When I had my TH350 rebuilt I had a shift kit and a 2200 stall converter installed and I don't remember exactly but I think the rebuild and install was around $1000. Granted, the two transmissions are completely different....

 

[HotRodPC]

$1000 just for the part? Wow! When I had my TH350 rebuilt I had a shift kit and a 2200 stall converter installed and I don't remember exactly but I think the rebuild and install was around $1000. Granted, the two transmissions are completely different....

Yep, totally differant. Trust me, a 700r4 is a POS. But, it can be made to be a good transmisison, it just has to have alot more done to it where the T350 needs very little done to it, and a T400 even less. So your T350 is probably about equal in strength to his 700r4. Although if his input shaft is hardened and the input drum is sleeved, he may have that edge of yours in stength, and yes a T350 can break an input shaft. I've done it once. Although if you are going to break a trans, that's the kind of break you want. It shears off and then done !!! No shavings to speak of, and no other damage to the trans since the pump stop immediatly in that scenario and doesn't circulate any bad shavings or dirty fluid. When that happens, simply pull the trans, the pump, and there it is. Take the forward and direct clutch drums out, put a new input shaft in the assembly, reinstall, torque pump, reinstall and back in action.

 

[Old77]

I've thought about swapping out my TH350 in favor of the 700R4 because with the TH350 my RPMs are so high at highway speeds with only having the 3 speeds. At 70 mph I'm up in the 3000 RPM range and I'd rather been down around 2200 or 2300. I know that the swap is not just a straight swap as I'd have to fab a new mounting bracket and a shorter drive shaft but from I'm reading from you it'd take a lot more to give it the strength I'd want? I had not heard this before. I'd heard some bad things about the 4L60E but not too much about the 700R4's.

 

[HotRodPC]

OK, I was lying. Its not a $1000 for the input shaft only. I had to go recheck, and I guess in my head, I say its $1000 but thats also for the hardened output shaft too. $420 for the front hardened section, and $639 for the hardened output shaft made of 300M. The front shaft is just electically hardeded to be 57% stronger. I'm sure that where I got the $1000 from. Sorry for the scare.

 

[HotRodPC]

I've thought about swapping out my TH350 in favor of the 700R4 because with the TH350 my RPMs are so high at highway speeds with only having the 3 speeds. At 70 mph I'm up in the 3000 RPM range and I'd rather been down around 2200 or 2300. I know that the swap is not just a straight swap as I'd have to fab a new mounting bracket and a shorter drive shaft but from I'm reading from you it'd take a lot more to give it the strength I'd want? I had not heard this before. I'd heard some bad things about the 4L60E but not too much about the 700R4's.

The 700r4 is junkier than the 4L60-E. The E has problems with solenoids and electrical computer issues, but can you really blame that on the trans? Not really. But the 700r4 was such a POS, every single year, improvements were made. Then about the time its becoming an OK trans, now we switch it up with a new set of problems going to -E models. But as far as the hard parts in a 4L60-E they have the better technology design changes in the strength area. Lucky for us, most of the 4L60-E parts are backwards compatible to the 700r4, so you can update the 700r4 with the newer stuff in most cases, but not all. Where you want as far as a 700r4 build, is with an 88-92 700r4 case. (93 went to 4L60-E). So avoid the 82-86 700r4's when possible. The 87 is an OK unit too, but with the changes from 87-88, the 88-92 is preffered. Now many 4L60-E parts are NOT interchangeable in the 82-86 700r4. Just best to find a 88-92 and be on the safer side. I could post more here, but It would get to long.

 

[HotRodPC]

There are pro's and con's to the 350 vs 700r4. IMO, the winning transmission would depend on what you're using the truck for. T350 is stronger of course, needs less done to it to handle some abuse. 700r4 has a deeper first gear which is great for taking off, or pulling something at take off. BUT, the 700r4 has a very wide ratio between first and second, so you can potentially get that fall off in the shift to 2nd, so racers usually wind up first gear real tight over their power band range, so that when they hit 2nd, they are still at the bottom of their power band range. No need to do that in a T350. Of course the obvious OD in 700r4, no explanation needed. But, for you nice cruising 77, yes you need a 700r4 and would be the practical proper choice if you drive it on the highway at 70mph. I myself like 700r4 because you can run alot lower rear end ratio, which is a torque gain for sure, and also takes strain off the 700r4 helping it last longer, so with the 700r4 you can have the best of both worlds. A low 3.73 or 4.10 rear end ratio, but yet have OD to compesate for it in the big end.

 

[Old77]

All GREAT info man!

When looking at a 700R4, what "era" tranny it is to determine that it's an 88-92 unit as opposed to the earlier units?

 

[HotRodPC]

BTW, and I hate to keep muddying up the new guys thread, but we are staying on topic of his built 700r4 aren't we??? To converty your Old77 to a 700r4 is going to be alot less headache than you think. Good chance you might NOT have to cut your driveshaft. There is only 5/8 inch differant in the 700r4 and the Intermediate output shaft T350 which is what you should have in your truck now. The trans with the 9 inch tailshaft housing. The yokes are also the same for T350 and 700r4, so dshaft might just bolt right in, no mods needed. The shift likage is in he exact same spot as is the cooling lines. You can likely also use the same brackets on the carb for your 700r4 TV cable the T350 is using for the detent cable. The same trans mount too and crossmember, just have to move the crossmember a couple inches. The only other thing to addess would be the TC lock up. There are kits sold to fix that issure for about $40 or so.

 

[87BlazerBeast]

everything you can do to it was done. I'm going to have to dissagree with you on that,i like 700r4 more than the th350.

 

[crazy4offroad]

If it wasnt so expensive to mod it to get it to work in my truck, I'd like to have the 4L80E. Price is another reason the TH350 is still widely liked.

 

[HotRodPC]

Yep, if you can do wo the OD, T350 is a great trans, very cheap, and very plentiful and very durable in an OEM form. Change a few parts and its pretty damn strong, unlike the 700r4, you have to basically revamp every aspect of a 700r4 to make them good. As 87BB said, he spent $3000 on a 700r4 build. I bulld a T350 just as strong for less than $1000.

 

[HotRodPC]

If it wasnt so expensive to mod it to get it to work in my truck, I'd like to have the 4L80E. Price is another reason the TH350 is still widely liked.

There is way to put a 4L80-E in your truck for alot cheaper than you'd think. The big expense is the aftermarket computer. You can do without the computer if choose to go full manual valve body.

 

[crazy4offroad]

Full manual meaning you have to shift each gear, and downshift as well? From what I understand th 4L80E is stout as the TH400 but with OD and no HP loss.