2.73:1 Rear - Do I have a chance in hell to......

[Ricko1966]

Well, I've seen people make that statement that if it doesn't lock, the trans will overheat... But I didn't really believe that... All trans prior to lockups didn't "overheat". But if this was because early 700r4's were questionable, well, I believe they were, but lack of lockup is not what burned them up. Glad at least the trans I put in it is from 1989.

I'd love to hook up and go, but the trailer is in storage and covered. Winter here.... I figured some guys already "lived this scenario" and would have a tale to tell.

I see a lot of people target 2800rpm as the optimum for towing with a 350/305. I think in Drive (3) with lockup, I'd be a little over 700 rpm under that. I suppose I should see where peak torque was on this 305. I got time for armchair quarterbacking right now!

Thanks for all the comments !

They overheat if they don't lock up in 4th gear because they starve for oil. And you do not want to tow in 4th gear with a 700r4 anyways.

 

[bucket]

They overheat if they don't lock up in 4th gear because they starve for oil. And you do not want to tow in 4th gear with a 700r4 anyways.

Right.

No lockup in 4th gear: Bad

No lockup in 2nd or 3rd: No Problem

 

[AuroraGirl]

Well, I've seen people make that statement that if it doesn't lock, the trans will overheat... But I didn't really believe that... All trans prior to lockups didn't "overheat". But if this was because early 700r4's were questionable, well, I believe they were, but lack of lockup is not what burned them up. Glad at least the trans I put in it is from 1989.

I'd love to hook up and go, but the trailer is in storage and covered. Winter here.... I figured some guys already "lived this scenario" and would have a tale to tell.

I see a lot of people target 2800rpm as the optimum for towing with a 350/305. I think in Drive (3) with lockup, I'd be a little over 700 rpm under that. I suppose I should see where peak torque was on this 305. I got time for armchair quarterbacking right now!

Thanks for all the comments !

lockup trans use different materials than non lockup. a th350c will burn up if it doesnt lockup.
Maybe the fact most modern ones are designed to stay locked most of the time and only be unlocked partially for NVH with barely any slip (so barely heat or wear)

 

[bucket]

lockup trans use different materials than non lockup. a th350c will burn up if it doesnt lockup.
Maybe the fact most modern ones are designed to stay locked most of the time and only be unlocked partially for NVH with barely any slip (so barely heat or wear)

I dunno, I ran a th350c with no lockup for several years and never hurt it. It only got replaced because I engine swapped the truck and put in a th400.

 

[Ricko1966]

700r4 uses pressurized oil from the tcc circuit to help lubricate one of the planetaries,look at a GM transmission hydraulic chart.They changed pumps 86? so they oiled better,but still no lockup is risky business. Proper way to go no lockup,is a pump modification remove the checkball from the pump shaft,and run a non lockup converter and the guys that do that don't even seem to have luck keeping them alive as long. Not that this is scientific,but I like the example. A guy on a different forum has been through multiple 700r4s,same truck. Trucks on its 4th transmission he got 5 years out of the 1st 2 running lockup,he got 1 year out of the 3rd one,no lockup,he's on his 4th and running lockup. The significance,in my opinion is the guys who say"I haven't had a problem" well neither did this guy immediately. Maybe it's like smoking it doesn't kill everyone,but it kills enough to know it's not a good idea.