88 Burb, 350 w/ 700R

[mmeth83]

Hey Guys,

I bought the Suburban from a guy that used it as a wrecker. He told me he had the transmission, a 700R, set up for the extra weight of pulling a 12,000 trailer and a vehicle on it, easily handling more than 15,000 pounds.

Any idea what modifications he is talking about? I like the idea of maintaining the capability; I eventually want to pull at 15,000 travel trailer with it. Are there others mods, I can try, like gear ratio?

I do want to keep the 350 in it. It’s getting about 14 mpg on the highway now and it’ll get a lot of use.

Thanks!

 

[bucket]

It's really hard to say. One person might simply install a trans cooler and then say it can handle whatever you can throw at it, while another person might build the trans with every HD part available and then say it's only safe to pull a little pop-up camper.

Without a full rebuild to be sure of what's been done, all you really can do is try it. But steep gears (your stock ratio should be 3.42 or 3.73) and a big cooler are a must if you want it to have a chance. And a trans temp gauge so you know when you are cooking the fluid.

 

[yevgenievich]

15k load pull is a lot for a 700r4. As mentioned above, big cooler and temp sensor are needed. 15k load is more in a th400, 4l80e territory.

 

[mmeth83]

Is the th400, 4l80e

15k load pull is a lot for a 700r4. As mentioned above, big cooler and temp sensor are needed. 15k load is more in a th400, 4l80e territory.

Can the th400, 4l80e bolt on directly to the 350?

 

[74 Shortbed]

Yes same bolt pattern.

 

[1987 GMC Jimmy]

I'd do the 4L80E with a standalone controller so you can have that overdrive when you're not towing a monster load.

 

[rt66paul]

Make sure to keep it out of OD when towing. It can get real espensive.

 

[Honky Kong jr]

Make sure to keep it out of OD when towing. It can get real espensive.

What he said heat kills transmissions. Plain and simple.