[mrboyle]

I have a TH700R4 in my Explorer (AA kit) with aprox. 25K on it. Until recently it worked perfect. In the past few days it has started to slip on the 2-3 up shift and will not hold overdrive if under any load. Fluid is full and clean.

Some things you should know about the tranny. The TV has always been a little tight (had to back off throttle to get it to drop into OD) and the lockup on the torque converter has been hit and miss (it worked fine on flat land but not so well if pulling a grade).

Any thoughts as to why all of a sudden it started acting up?

 

[Grumpy_old_fart]

I have a TH700R4 in my Explorer (AA kit) with aprox. 25K on it. Until recently it worked perfect. In the past few days it has started to slip on the 2-3 up shift and will not hold overdrive if under any load. Fluid is full and clean.

Some things you should know about the tranny. The TV has always been a little tight (had to back off throttle to get it to drop into OD) and the lockup on the torque converter has been hit and miss (it worked fine on flat land but not so well if pulling a grade).

Any thoughts as to why all of a sudden it started acting up?

its a 700r4?

not asking... just stating that since you already identified the problem, why not get something more appropriate for the task at hand?

this is an opinion, not a complete bash. the trans was made for a car, adapted to other applications. the problems you describe are simply a good indication that you are asking more than it can provide.

 

[bc shredder]

do you understand how a trans works???

You dont want the converter locked up pulling a grade because it sevearly limits the fluid flow to the trans cooler (you doo have a good cooler right). Grump is right slipping shifts just means you have worn out the trans. One of the best things you can do for an auto trannie (as specially a 700r4 is a nice big cooler) Don't let that trannie get hot that is what killes them.

 

[lumpdog]

You dont want the converter locked up pulling a grade because it sevearly limits the fluid flow to the trans cooler (you doo have a good cooler right). Grump is right slipping shifts just means you have worn out the trans. One of the best things you can do for an auto trannie (as specially a 700r4 is a nice big cooler) Don't let that trannie get hot that is what killes them.

Typical 3/4 clutch failure.


Pull the trans and get a good HD build.

I like the 700, and prefer it over other trans... But to each his own. A 700 built and installed correctly will give you years of great service, I have been thrashing on them in my rigs for a long, with great results.

 

[mrboyle]

its a 700r4?

not asking... just stating that since you already identified the problem, why not get something more appropriate for the task at hand?

this is an opinion, not a complete bash. the trans was made for a car, adapted to other applications. the problems you describe are simply a good indication that you are asking more than it can provide.

You think the 700 is weak, you should compair it to the pos A4LD that Ford put in the Explorer stock. Now that is a weak tranny! I seroiusly doubt I'm asking "more" than the tranny can do considering the engine has 237K miles on it and I've seen 700's hold up just fine behind built V8 engines just fine. As far as the cooler, it has a large cooler on it, so I doubt it has been overheated.

Typical 3/4 clutch failure.


Pull the trans and get a good HD build.

I was afraid that was the problem.

 

[Grumpy_old_fart]

You think the 700 is weak, you should compair it to the pos A4LD that Ford put in the Explorer stock. Now that is a weak tranny! I seroiusly doubt I'm asking "more" than the tranny can do considering the engine has 237K miles on it and I've seen 700's hold up just fine behind built V8 engines just fine. As far as the cooler, it has a large cooler on it, so I doubt it has been overheated.

you state the 700 is a good trans, yet it suffered from a "typical 3-4 clutch failure". this means that this problem exists in this trans. think about it.

 

[lumpdog]

you state the 700 is a good trans, yet it suffered from a "typical 3-4 clutch failure". this means that this problem exists in this trans. think about it.

Every trans has its typical failure..


You always recommend the 400. Yet the 400 has been exhibiting typical direct clutch failure causing loss of reverse and 3rd gear. 4l80e's use the same setup, and it is the most common failure I see in them as well. Which then leads to a center support and direct drum replacement.

Every trans has it's weak point. But, almost every trans when properly built with upgraded parts will last for years.

Everyone knows that a factory 700 was built with soft shifts and durability issues. But with a good shift kit and a few upgrades, they can be built to be very strong and reliable.

Biggest problem I have seen with 700's??? The rebuilder themselves being sloppy. This trans can't handle the old 350/400 building technique of just slapping it together without checking clearances and tolerances, or using sub par parts. Second biggest failure cause? It's during installation. It is amazing to me to have personally dealt and built transmissions for local repair shops who still don't understand how important the TV adjustment is to the life of the trans.

Sure, the 350 could be built by as monkey in a sandpit and still work, but this ain't the 1970's anymore......

We could go on the 700/400 debate for years. And probably will.

 

[florida4x4]

Oh dang, going down this road again :flipoff2:

I hate the way my 700R shifts but it's going strong with over 150k on the clock. Original owner swore it was never rebuilt. The burb has the factory towing package and I've put an additional cooler on it.

 

[onecrustyman]

At what temp should a 700R run?

 

[lumpdog]

As a general rule of thumb, trans temp shouldn't read higher than engine temp, so around th 200 degree mark. I wouldn't run it over 250 degrees to be safe.

My Dodge diesel with OD and a non lockup converter runs about 200 degrees in the summer pulling 20,000 lbs.

I consider 200 and lower good, 200 to 225 acceptable, 225 to 250 ok in short durations, 250 to 275 WARNING, 275 and up...Trans Death..

Now these are pan/case fluid temps, not hotline converter temps.

 

[mrboyle]

lumpdog, do you think that running the TV cable the way its been (having to feather the throttle to get it to shift into OD) may have caused the premature clutch failure?

 

[lumpdog]

lumpdog, do you think that running the TV cable the way its been (having to feather the throttle to get it to shift into OD) may have caused the premature clutch failure?

No, I don't. A tight TV causes higher line pressure readings, which is what is causing the upshift as you describe. There is a possibility that the higher pressure blew out a seal, but that generally only occurs when you have worn parts and/or damaged seals to start with.

 

[mrboyle]

Thanks. I've never been happy with the converter I installed, so I guess this gives me a good reason to swap it with a higher stall.