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Help! Any advice on a 700R4

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Wicked86

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Looking for anyone out there that knows of a better 700R4. I've been through 3 of these so far with no similarities in cause of failure. My current boat anchor lasted 4 mos. with approx. 5,000 miles - no warning just like she went into neutral and thats it. Granted it gets driven, but there has to be a better way. One final note, the previous unit was a TCI that grenaded.. Any thoughts or ideas would be helpful.. :doah:
 
There are three major things that kill a 700R4, wrong axle gearing, heat, TV cable not properly SET.
 
How are you setting the TV cable? What is the line pressure?

What size tires do you have and what axle ratio?

I think the highest recommended 700's here are from Bowtie Overdrives and GM.
 
Thats just it..every install has been by the book. Line pressure I cant recall... I thought for sure that the TV cable was the issue but it wasnt. Frustrating more than anything....
 
Tires are 33x10.50 axle ratios are 3.08 and driveline is stock 10 bolts front and rear.
 
Thanks for the response..axle ratio and tv cable are fine..like I said this is the 3rd one im doing and Its starting to wear on my patience and wallet...
 
Im sure it isnt, but its driven on the street..should be able to last a tad longer til I can resolve the gear ratio and tire issue.
 
HA been thinkin that exact same thing..but also know a GOOD 700r would be ok too..With winter slowly setting in I will have a bit of time to research whats gonna happen here..
 
One other thing came to mind, after each failure did you properly flush out all tranny lines and trans cooler? There could be contaminates in the lines and cooler itself which can ruin a new tranny in short order.
 
Hey..Yeah I replaced both trans. lines and installed a heavy duty trans. cooler. I am relatively new to transmission work, but I appreciate your input, would be nice to pin point what went wrong, ya know? Hard to see when its still in the truck. Wisconsin weather demands storage for now, getting my ducks in a row so to speak....
 
By the way heres a few details - 86 K5 .040 over SB Chevy, edelbrock intake and carb, hooker full length headers, full exhaust. Body has a 3'' lift. 33'' BFG ATs. Interior is all there but needs some TLC and a good clean up. Jesse--
 
Wicked86 said:
Tires are 33x10.50 axle ratios are 3.08 and driveline is stock 10 bolts front and rear.
Click to expand...

Swap to 4.10 gears and it will feel like a big block swap. As an added bonus, the tranny will live longer.

Where did you get these 3 transmissions from?
 
I've been running 35's with 4.56's f/r for the last few years in my 86 700r4 without any problems. It does have a shift kit in it though, even though that probably doesn't make a difference as far as longevity.
 
The first was a stock but rebuilt, the second a TCI, and the third was out of a wreck Believe it was a hipster. Ok..so after the trans issue my next question would be: Will my 10 bolts handle an aggresive gear ratio change or am I lookin at another upgrade?
 
Screwed up but posted an answer. Dont get me wrong, the motor I did has more than enuff, but yeah the trans is definately the weak link. Just tryin to go the best route as far as durability. The last trans had a shift kit and a 2400 stall and seemed to do ok...
 
I have 30k miles on my rebuilt 4L60. I was running 33's with 3.73's, then I swapped to 4.56's, and now I am running 37's. Tranny was built with the "Right Stuff", and I have the TV cable set a tad on the agressive side (IOW, you KNOW when it shifts, but it's not harsh :D).

That said, if you like to rod the piss out of your truck (i.e routine full throttle launches, etc.) you're not going to get as much life out of one. It should still last a lot longer than 5k miles though. TV cable adjustment is critical on these, and it's WAY better to have too much (firm, late shifts) than not enough (early, soft shifts and slippage).
 
I had brought up the TCI Constant Pressure Valve Body in a prior thread. I'd love to see some results from someone actually using it.

It removes the TV cable (line pressure) from the equation. The TV cable is still used, but only to set shift points.

www.tciauto.com/WhatsNewFilestci1982-86700r4constantpressurevalvebody2.pdf

I'd start with one of the good, later 700R4s, have a good reputable shop build it with the good mods, add the valve body, and run a cooler on it. Make sure you have a tranny temp gauge too.

Also, ditch the 3.08's. They bring teh suck. Even on my 31" tires, it sucked. Install 3.73's or 4.10's and you'll be MUCH happier...so will the tranny.

Edit: Another TCI link: http://www.compperformancegroupstor...Screen=PROD&Store_Code=TC&Product_Code=376020
 
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