700R4 Slipping in 4th Gear - why?
 

Hey everyone,

Got a rebuilt standard 700R4 w/OD from Monster Transmission 2 years ago for my '70 C10 2WD with a '69 396. Open differential. Been a great tranny up to a few months ago. At low speed in 3rd or 4th, occasionally I felt a shudder and lack of acceleration once warm, then it would grab and go. Fluid level always good, shifts fine, everything else good.

But yesterday, about 5 mins into the drive, in 4th about 40 mph, when I tried to accelerate with just normal effort it won't accelerate and the rpm rapidly climbs. Doesn't seem to do that in first 3 gears. I took it straight home. It's still under extended warranty, Monster asked I take it to a local tranny shop here in Las Vegas.

Anyone have an idea what this could be? I really appreciate the help. It's been a great 700R4 til now.

Re: 700R4 Slipping in 4th Gear - why?
 

It is headed south. Time to pull it and do a rebuild.
Jimmy

Re: 700R4 Slipping in 4th Gear - why?
 

Time for a rebuild my friend i try not to talk about about company's but the fact u got 2 years out of a monster transmission is amazing local shop get them in all the time after the fail and monster declines warranty repairing. If u google there reviews they have alot of issuses find you a good local shop to build it and tune it for ur truck.

Re: 700R4 Slipping in 4th Gear - why?
 

3/4 clutch is dying...behind a 396 you were lucky to get 2 years...

Be careful with Monster...

What stage trans did you buy?

Might be a good time to upgrade to an 4L80e and have it professionally built....

Good luck...

:chevy::chevy::chevy:

Re: 700R4 Slipping in 4th Gear - why?
 

I appreciate all the replies. Oh boy, just looked at BBB complaints, never seen so many in my life. It is a Level 1 firmness, mild factory shift, 1800-2000 torque converter. I'm the only driver and I drive it easy, not hard.
Monster sent me an ATRA.com link to find an authorized shop. I think I'll use Transmission Service Center, them seemed good when I took my old TH400 by when I first got the truck. Motor has a mild cam from PO, prob has about 360 hp is my guess. Only have about 8,000 miles on the 700R4.

Re: 700R4 Slipping in 4th Gear - why?
 

If you decide to ditch the 700 for modern, you’ll need a trans controller. I have a 4l80 behind my 67 with a US Shift controller.

Side note, I could have swore I saw your truck driving down Lamb by Pic-A-Part the other day. Nice truck.

Re: 700R4 Slipping in 4th Gear - why?
 

Gm never put a 700R4 behind a big block for a reason.

Re: 700R4 Slipping in 4th Gear - why?
 

Tom...never has a truer word been spoken....

Chew em up and spit em out...

:chevy::chevy::chevy:

Re: 700R4 Slipping in 4th Gear - why?
 

It's not the HP that hurts them. It's the BB torque

Re: 700R4 Slipping in 4th Gear - why?
 

Yup. 600lbs/ft at 1000rpm isn't even 150hp, but it will tear the crap out of your driveline when starting off from a stop.