Hello, can anyone help me out.
I have a TH700R4 in my rig, and i have blown two of them this summer.
It`s starts with slipping in reverse and then forward. It`s seems to be too much oil when this occurs, but when the automatic cools down it`s seems to be correct. The same with both of the trannies. When the tranny is cool i can drive it a while before the same occurs.
What can this be:confused:

http://www.bilbygging.no/download.php?id=6834

And yes, the TV wire is correct adjusted

Sounds like the oil is overheating. Do you have a oil temp gauge for the tranny?

Sounds like the oil is overheating. Do you have a oil temp gauge for the tranny?

No, I don`t have any oil temp gauge.
The rig is only driven four minutes a time. The transfer in LO and the unimog axles have over 7 to 1 ratio, can I overheat the tranny with that??

hmmmm


just an observation....


why dont we see complaints about the TH400?

I burned through my first pullout 4l80e (TH400 + OD) in a couple of months. The home built rebuild is holding strong. Just making sure we're aware the TH400 is not bullet proof, just stronger.

You can easily overheat the fluid even with a ton of reduction and short use if your putting a ton of power through the transmission. Get a large cooler on that transmission and given the symptoms you gave the problem should be rectified.

I burned through my first pullout 4l80e (TH400 + OD) in a couple of months. The home built rebuild is holding strong. Just making sure we're aware the TH400 is not bullet proof, just stronger.

You can easily overheat the fluid even with a ton of reduction and short use if your putting a ton of power through the transmission. Get a large cooler on that transmission and given the symptoms you gave the problem should be rectified.


Im not talkin about a 4l80e. I meant the th400. you see sooo many fewer failures with the 400 than you do with the 700r4 that its pathetic. so, using common sense, why not use the th400?

sure, it "robs" you of some power... but if youre in low low in the double transfer case, do you even notice it? Im willing to bet that most rockcrawlers are based on a simple 300 hp engine anyway. Thats why the gear reduction is needed, because without it, you would have to be screaming to get over an obstacle. there goes control...

simply put as an observation, the transmission should be the toughest thing you can find. Marginal parts provide marginal performance.

besides, wtf do you need a 700r4 for in a buggy?

A 4l80e is internally a TH400 plus some upgraded and updated peices and an OD assembly. Most of the TH400 gear train parts directly swap even. Mine didn't fail because of the electronics, it looks like one of the roller clutches failed and then wiped out a couple bushings which sent particulates everywhere.

The 700R4 has a better 1st gear and is 80lbs lighter. It shouldn't have an issue pushing a light buggy. I'm sure that 80lbs means something to them. Yes you can argue that you want the trans bullet proof so the extra weight is ok, but then what about the 404/406's, should the axles be bullet proof too? Do they really need U1300's/419's? It's a snowball effect and the result is ridiculous amount of added weight that really isn't needed if you build the lighter parts right.

No, I don`t have any oil temp gauge.
The rig is only driven four minutes a time. The transfer in LO and the unimog axles have over 7 to 1 ratio, can I overheat the tranny with that??

Yep, you can overheat that way obviously you'd have to be running it hard though. Not sure what you do for 4 minutes...rock race??

Anyway, are other competitors running 700r4's with the same drivetrain, tranny cooler, etc without issues?

it weight was an issue, they could run a shorty glide.

is there even a trans cooler on your rig???

it weight was an issue, they could run a shorty glide.

Maybe they need the deep 3.06 1st and the .70 OD for the run? Or maybe they just need the length from the front axle for the front driveshaft? Or maybe it's an avalibility thing being their location?

In any case, his issue was how to make his overheating tranny work. The answer isn't always pull out that thing and put this heavier thing in, sometimes just building a system right works alot better.

good point.

its just my opinion that if you built it right the first time, you wouldnt have to redo it and throw more and more money at a failure prone part.

is there even a trans cooler on your rig???

Yes it has a cooler, even with fan

Check your "line pressure" with a trans pressure guage. My WAG says your not building enough pressure and your plates are slipping. Bow Tie Overdrive has alot of info http://http://www.tvmadeez.com/article/part3.php

By the way, I wheel and DD a big fat Jimmy for the past couple of years with BTO stage II 700R; no failures :D

Check your "line pressure" with a trans pressure guage. My WAG says your not building enough pressure and your plates are slipping.
I had a problem with my 700r4 slipping. I put a line pressure guage on and watched the line pressures while I was wheeling. Mine has all the good parts in it so I didn't want to fry it. Ended up being my pump. It had the aluminum style pump in it. I swapped in a cast steel pump from a newer 700 and all is good again.