700R-4 Wont go past 4000 RPMs

[85-BURBON]

I have a 85 K1500 Suburban the trans shifts and runs perfect. The only thing is when you have it to the floor the trans will not go over 4000 RPMs. It has been fully rebuilt and has had some valve body work. My uncle built the entire truck but recently passed away. I am just curious what would cause this and if anyone has an idea why my uncle would set it up this way. I know he did it this way for a reason. Is is the valve body not allowing it to go past 4000 rpms or something else??? Any insight or advice would be much appreciated!

Its a rebuilt 350, 4" lift, 35" procomps, and much much more....

 

[HotRodPC]

I'm not understanding the problem. Are you talking it shifts before 4000 rpm even to the floor? You have it in manual 1st and it won't go over 4000 or what? What happens when you put in it in first and hold it there? Can't get over 4000 in OD? If that's the case, with big 35's in a heavy suburban an in OD, that's probably all the power the motor has. Try it again going downhill and see if it gets over 4000. At any rate, you need to explain a bit better. If you think it's shifting a bit early at full throttle, maybe tighten up the TV cable a hair. I just don't know what you mean exactly.

 

[foamypirate]

4000 RPM seems like a pretty normal shift point for a smog era 350. No sense wringing it out much higher than that unless it's got a cam or work done to it.

 

[HotRodPC]

4000 RPM seems like a pretty normal shift point for a smog era 350. No sense ringing it out much higher than that unless it's got a cam or work done to it.

That's what I'm thinking, especially for a 700r4. They don't like RPM and will split the input drum. This is why if I'm building one and I know it's a bit HiPo, I sleeve the input drum with an aftermarket Sonnax kit.


But we don't know if he's talking shift points, top end, manual shifting or what. Hell the motor might be petered out at 4000 running heavy 35's on a heavy Burb if it's an OEM stocker smog riddled cam spec.

 

[85-BURBON]

In OD at full throttle itll shift right at 3900-4000 rpms. I do think it does have a little to do with tires and overall size of the thing. The engine has a fresh build on it as well. Nothing crazy just a fresh mild rebuild. I feel like it is shifting a tad bit early. I dont have much experience with 700R4s. Ive had a few TH350s' and 400's but not a 700R4. If you put it in 1 or 2 it will go past the 3900 mark but not in OD. Is this normal for a fresh 700R4 with a decent engine in front of it?

First post Ive made here appreciate the help everybody?

 

[HotRodPC]

Sounds about right to me. Consider the tire size and a 30% overdrive, consider the strain you're putting on the engine and that transmission for that matter. OD gives you a torque loss, it's just for cruising once you've reached your desired cruising speed. Do you get over 4000 rpm in D or 3rd?