ACK! My beater needs a transmission!!!

[the_experience03]

230,000 miles is plenty on any transmission, especially a 700R4. I agree with you that it has an unnecessarily deserved bad reputation. However, all reputations have their roots in something. The high failure rate of the early 700R4's as well as GM's decision to use them in large diesel powered 1 ton trucks probably is one of the biggest contributions to this reputation. Still, hot rod guys all over the country flock to this transmission because it operates independent of a computer and gives them the overdrive to make their low gearing a little more tolerable on longer trips.

$600 is a smoking deal on a rebuilt 700R4. Heck, a used high miler goes for $400 or so in these parts. This is probably the route I would go. If you were looking to build a wheeler out of the truck there are other options that could be looked at (like that TH-350), but for a weekend warrior I think keeping it as close to stock as possible is important. The Turbo 350 is not without problems either. It just happens to be considered more reliable and the fact that you could repair it in a gravel pit with a set of tools purchased from the discount bin at Harbor Freight earns it a lot of credit.

The TV cable is the most important issue when setting up a 700R4...of course it is the only thing you should have to adjust. It's also extremely easy to do and takes all of 5 minutes. I wouldn't worry much about it. Heck, it's even a relatively easy transmission to change out thanks to the big inspection cover under the torque converter. I like not having to rotate the engine to get to the bolts.

Your mechanic is very intelligent when he tells you that a swap to a 5 speed is not worthwhile. On top of the cost involved with getting the transmission, crossmember, pedal assembly, etc, they can be a real bear on the S-series Blazers. More than once I've had to loosen the body mount bolts and jack the body up to get at that darn upper left bolt on the bellhousing. There is nothing more frustrating than being able to get a wrench on a bolt but not being able to turn it due to space. Or getting 3 feet of extensions on the impact with a swivel socket only to watch it fly apart and send extensions sailing everywhere the first time you hit the trigger...

 

[timbuk]

cheese i got 2 of those things in my yard one has 4.3 with od and one has 2.8 both have only 75k miles on them and both run fine.both are rusted out.too bad im in bc eh!

 

[JoeMonstermaker]

The 700R4 is VERY popular in the hot rod world. If I ever give up the four-speed in my '55, I'll put in a 700R4. The three rebuilds in 30 days experience has to be due to something not being done properly, not the design of the trans. I once put three Cadillac 500 motors in my Chevy truck in 30 days... two were just old unknown engines.

In my mind you have two good options: get the cheapest working trans you can and immediately sell the truck, then buy one with a 5-speed, or get a well-built 700R4 even if at a moderately high cost. Then, keep it out of overdrive anytime you have to use much throttle.

 

[bbbrt76]

a properly updated and rebuilt 700r4 will easily outlast the rest of that blazer no way I'd spend the money to go to a th350

 

[the_experience03]

Damn you, Vanguy! I just drove up to International Falls last night to pick up a new hoopty ('91 C2500 LD) for $600. I drove it all the way home without a problem. I got in it today to go to work and everything seemed fine...1st gear....2nd gear.....neutral....wait?!?!?!? Yep...a 700R4 that burnt up its 3-4 clutch pack. Now we're in the same boat only I'll only be spending $200 on my new-to-me-well-used junkyard tranny because...well...it's a junkyard beater. So...who is next to lose a tranny?

 

[bbbrt76]

Just wish I could put some 6-way leather seats with seat warmers in the new Blue Bird!!

go for it! you've got the seats now, I'm sure your wife will understand lol

 

[the_experience03]

It's a 1997 Deville D'Elegance with 93,000 miles on it. I drove it home! ALL the way home! Tranny seems to be good in the Cadillac!

You're lucky. A 4T80E is not a cheap or easy tranny to replace.

I think I have better luck than you. I got the deal on this truck through a good friend that knew the guy who was selling it (and it turns out he was just another middleman in it for another middleman that was in it...like 5 people involved in this $600 truck ). Anyway...my buddy called the guy up and is going to make it right. I didn't ask him to and I'm not at all concerned about it, but my buddy is which is cool. It goes to character for sure. Anyway...all I'm out is the use of the truck until Sunday when I get the new tranny installed along with rear brakes, a block heater, an oil pressure gauge (it's a Canadian truck and I don't like kilopascals or trust the factory gauge), and move the damn pitman arm. You can install the pitman arm 4 ways on those trucks. It would appear that someone did it wrong because the truck goes straight down the road and has the same number of turns lock to lock...but the steering wheel is at 90* to the left. Such is life with used vehicles. I like to just take it all in stride. Of course I don't spend much on my vehicles either.

 

[the_experience03]

Slop in the frame mounted bushings can make the transmissions not quite completely shift. What happens if you disconnect the linkage and manually shift the manual valve? Can you get reverse and park? It just *sounds* like your manual valve isn't moving completely from one position to the next and you will notice it most at the extremes of shifting, that is from reverse to park and from second to manual low.

 

[the_experience03]

I actually don't mind the little 700R4. It certainly has its issues, but no automatic built has even been without them. It's quite possible the manual valve is toast. That should be a relatively easy fix.

It's interesting that you're having such terrible luck. When I swapped that 700R4 into my pickup after losing the 3-4 clutch I did a very small amount of work on it. Supposedly it already had stacked plates on the clutches, but I never verified this. I did install a Gil Younger kit in the valvebody, have my TV cable one notch tighter than factory (giving me a 3-4 shift at 50-55 mph under light throttle versus 45 to put it in perspective), and I have a switch allowing me to manually drive the TCC or let the ECM drive it. Rarely does the computer get the chance to work it. I couldn't be more happy either. You'd never believe that a 7200lbs GVWR 3/4 Chevy with a TBI 305 (L03, 170 hp at the crank ) and a 700R4 would make much of a tow rig, but it does AMAZINGLY well. It's all in the finer details of tuning.

 

[Jarlaxle]

Tghe TH700/4L60E is an awesome transmission...I prefer the TH-200-4R, but the 700 is pretty good.

Sounds like you got a bad one from the boneyard.

 

[Jarlaxle]

That sounds like plain and simple incompetence on the rebuilder's part, no more and no less. The 4L60E in my old Caprice wagon was the second-worst trans the guy at Triangle had ever seen (the TC was had gotten so hot it was discolored)...I was still able to drive it about 14 miles from where I bought it to the shop (it wouldn't go past second gear), despite the trans being so cooked the only thing he was able to reuse was the case. (His best guess: the fluid might have topped 350 degrees.)

The idiot who owned it pulled a 6500lb boat with no tow package and trans cooler.

I've seen a TH-700 holding up to a 2-ton Super Bee powered by a crossrammed EFI 426 Hemi (yes, I absolutely did say it has a crossrammed EFI 426 Hemi) with an easy 550HP (it's a low 12-second car with 3.54 gears). The same guy has a TH-700 behind a 454 Chevy in a 10-ton Pace Arrow tag-axle class A motorhome. (He owns a shop that specializes in TH-700's.)

 

[the_experience03]

You should be able to get that transfer case into neutral by shifting the transmission to neutral and then simultaneously holding 4hi and 4lo while in 2hi. Of course I would still advise against flat towing it that way for any real distance.

 

[the_experience03]

Well now I'm not so sure given the age of that thing. My initial reaction was to assume it was a New Venture 233 transfer case which is part time and has the ability to go into neutral provided there is someway of inputing that to the TCCM. I know some of the with the old knob style required you to turn past 2hi to the "hidden" neutral position and others required the sequence I said. Now I'm wondering if you don't have the same Borg Warner 4472 transfer case used in the Olds Bravada. I suppose the easiest way to tell would be to crawl under and look at the tag on the t-case. If all else fails try and see if you can turn the front driveshaft by hand with the vehicle in park. Is there a disconnect on the long-side front axle tube?

 

[the_experience03]

Hey you...bringer of the transmission bad luck...

So here we are about a year later...I swapped a reasonable 700R4 (Alto stacks, Gil Younger kit, etc) into my beater C2500. Last Friday night it was -30 outside and I had to take a little trip. Wouldn't you know it...the 2-3 shift valve hung up just a little on the 2-3 upshift. The transmission decided to try and be in 2nd gear and 3rd gear at the same time. Now I have yet another 700R4 with the 3-4 clutch pack visible as black and sparkley fluid on the dipstick.

I sure do love automatics...

 

[spirit_of_76]

My 95 GMC Jimmy just lost o.d. Christmas eve and it's the best vehicle i have. Best of luck with your 94.

 

[the_experience03]

Well...my old beater is going be become an organ donor to my Toyota crawler. I had been driving it around with just 1st and 2nd in town when I heard what sounded like a roots supercharger under the hood at a light. Within 5 blocks the alternator locked up solid and killed the motor. I took the serp belt off and limped her on home (no big fear of overheating in Minnesota this time of year) and bought a new beater...another '91 Chevy with a 700R4. But...this one had 4 new tires put on it within 100 miles of me buying it. People don't do that to vehicles on their way to the big junkyard in the sky...I don't think.

 

[Jarlaxle]

[quote="spirit_of_76":3dy83jch]My 95 GMC Jimmy just lost o.d. Christmas eve and it's the best vehicle i have. Best of luck with your 94.

Unfortunately, I don't think a '95 can be swapped to a TH350. Probably the '94 can't either. Word of advice. Don't mess around with a used 700-R-JUNK or 4L60, they aren't worth the trouble, as you see from my experience. Much better off to have it rebuilt with updates.[/quote:3dy83jch]

The original 4L60E in my old Caprice went 108,000 miles, despite the idiot owner towing a 6500lb boat with no trans cooler (and no tow package, and a 3000lb hitch...and no wiring...). The trans guy's best guess: the fluid may have hit 400 degrees. The rebuild (stock except for a Corvette governor for firmer upshifts) was trouble-free with 60,000 miles (sold the car).

 

[the_experience03]

It doesn't have to be weak junk to be an overdrive. There are many overdrives out there that are pretty fantastic. The 4L80E is a pretty trouble-free transmission, as are the Dodge 46, 47, and 48 series transmissions once you get past the lack of a cold bypass on the older ones. Heck, I really don't even have issue with the 5R110 either aside from it needing expensive low viscosity fluid. And if we want to talk about lighter duty transmissions how about the Toyota A340/Jeep AW4? If you keep the fluid cool they last a LONG time without problems. There are just better designs and worse designed. GM seems to like the more complex designs which work WELL...when they work. But they get expensive in a hurry when something breaks and with that many moving parts something is bound to break.

 

[the_experience03]

Electronic controls are a GOOD thing though. Look at the newer transmissions used by everyone. They all have a tow-haul mode. This allows the transmission to up the line pressure and follow new mapping for upshifts and downshifts while still retaining a high mileage, low wear driving condition the rest of the time. You want a shift kit for your 4L60E? Cut the wire to the EPC solenoid and enjoy full line pressure all the time. Want your engine to heat up quickly? Electronic transmissions allow for logic that will warm up the engine faster by holding lower gears and keeping the converter out of lock up. Want the transmission to cool down faster when you're towing? They can do that too. A 41TE has logic in it that will lock the converter all the way down to 2nd gear to fight heat. Barring major mechanical hard part failure they will remain functional. How about diagnosing transmissions? It's no longer a guessing game when I can see specific clutch volume indexes or shift adaptives. Electronics aren't all bad. Remember...200,000 miles is the new 100,000 miles.

 

[bus-bro]

And 50 is the new 30.