700r4 help!

[Fancy]

So some of you may recall my original 700r4 went out at 170xxx miles. My buddy who had a 700r4 laying around after he totaled his truck gave me his with only 5000 on it after a rebuild/upgrade. I installed it myself and followed details closely as well as installed a aftermarket trans cooler by B&M and a after market trans filter by Derale. I payed extra close attention to the TV adjustments and followed the instructions. After install it ran good for about a month and then i noticed it got a hard shift from 1-2. On my way home it would not hit 4. I instantly tried to pull off the freeway when third acted like neutral. After costing to a stop it down shifted and 1 and 2 worked then 3 for a bit and again like it shifted to neutral. I pulled over at the safest place and checked fluid and saw it was low so i added a quart and since i was so close to home i drove the back way in 2 by shifting into second. Since it was dark and raining i didn't notice till the next morning my pan had been dumping fluid. I pulled the pan and resealed everything and adjusted fluid levels again. I noticed no metal shavings but alot of fine black dust. (im assuming clutch dust). still this didn't fix anything. o yea internal filter looked clean and had just been replaced.

Any ideas would be great! unfortunately if i have to replace the trans it is probably bye bye truck for me as i have no money and have already dumped to much into it. So any help would be appreciated.

 

[Fordum]

Not sure if that model has a governor or not. I know on the ones that do, that can cause those symptoms.
What happened to your old tranny? Between the two, you might be able to do a rebuild yourself.
You would not want to take used soft parts off one and put on the other, but a hard part in good shape would be usable.
Several people have rebuilt those successfully.

I understand the kit is fairly cheap, and you have lots of folks here to help with directions.

Don't know what a junkyard tranny would run, but if the price is right, you could get one with a 90 day warranty while you build a good one.

 

[Fancy]

hey thanks for the quick reply! Ya they have governors i just don't know much about them to know what symptoms would be linked to that. What would be an example of a soft part?

I still have the old tranny and it actually kind of went out the same way except no real forward gears barley moved in first as i recall. I was told it was toasted and to replace it.

Could it be something other than the tranny causing this? like a bad t-case?

 

[GMCSuburban2500]

It's unclear in your post (or I'm just missing it - that happens)

Did you fix the leak and refill the trans fluid to the proper level? if so, how does it work?

you can run them low on oil a short time and they'll survive... you certainly cut it's lifespan, but chit happens, right?

EDIT: Reread your post... looks like you refilled it and nothing... probably toasted then. Sorry.

 

[Fancy]

Sorry ya im new to transmission and i do not have a tach to help with knowing rpms. I fixed the leak and refilled it yes (mobil 1 ATF) to proper level (actually a hair over). After taking a step back and rethinking it. Im thinking what is happening is this. It shift from first to second LATE and firm! i say this becuase as i accelerate i can feel my RPMS rise high and then SHIFT i don't want to say hard shift but it is sudden and jolts sort of. Then again for 2-3 except smoother. Now this is where it gets tricky i can feel the rpms again increasing and then they spike and its like im in neutral almost. I want to say as if it shifts into fourth and no forth but i don't feel a shift. It feels like im in third and then no third. but when i slow down and start over same thing.

 

[GMCSuburban2500]

Hmm.... Sounds like slippage, but I have to agree the governor may be at fault too... had a TH350 that did that. Probably the easiest thing would be pull the gov... check for free movement of the weights, then mic the lands. Don't know what the spec is off the top of my head... .800 inches or something. Too small (worn out) governor or sticking weights could do this.

 

[Fancy]

Thanks i will most likely check the gov first! the trans did sit in my buddies shop for quite some time i guess! (a few years he thinks) not sure if that helps.

Also it is 3rd that is acting like neutral (or slipping if that is what slipping is)! I drove it in drive and it dose the same thing. from what i know OD is the fourth gear so it would not shift into fourth if it was in D right? Thus it is third that is acting like neutral or slipping

 

[Fordum]

What would be an example of a soft part?

Welllll, I kinda used the term loosely. A hard part would be like a gear or shaft. A "soft part" would be like a clutch or brake band. Things that normally wear. A gear wears too, but you would expect a gear to outlast the clutch many times over.

If a gear or shaft or shell, something like that, I would not hesitate to reuse it if it looked good.
But I would only try to reuse a clutch plate or brake band in an absolute emergency.

Most of your rebuild kits have seals, brake bands and clutches mostly.

It sounds like you may have lost 4th gear for some reason. I would reset the TV cable first thing. Its easy to set, and can destroy a transmission if it has gotten out of adjustment.

Then pull the governor and see if it looks ok and moves freely. Again, I don't remember on that tranny, but on most its accessible from the outside.

Also, check the fluid again. It might have had an air bubble and did not read correctly.

If you had a lot of dust, it might have caused a valve in the valve body to stick. Never worked on one of that model, but have pulled the valve body on older ones. If its not to tricky, you might be able to pull that one and clean it.

There are a lot of guys on here who have rebuilt their own, and a few that have rebuilt lots of them. Hopefully they will chip in soon.

 

[bigblock72]

The transmission is done. The 3-4 clutch is burnt to nothing, yours is a classic case where you lost OD first then lost third. Most likely caused by low fluid level that caused line pressure to drop enough to allow the clutch to slip, that particular clutch won't tolerate much slippage before steels start to cone and once the steels cone there isn't much contact between the clutches and steels that further aggravate the slippage issue. By the time you noticed the problem it was too late.

The best cure for that is to have the rebuilder install a Raybestos Z-pack in that clutch, DO NOT use the thin clutches and steels that most rebuilders use to get 9-10 (stock is 6) clutches in the 3-4 pack. The thin steels will overheat and cone even faster than stock steels and will not live in a truck (ok in a car) where the design of the clutches in the Z-pack will tolerate a lot more slippage before anything bad happens.

Sorry for the bad news and be careful when shopping for another trans or rebuilder, the 700r4 is a good trans if built properly no matter what the "pros" say.

 

[THRILLBILLY]

had the same shift issues with my 700r4. mine unleashed all hell at once though, turns out the govenor gear was shredded, 4th clutch pack was shot, servo was toast, band was gone, and a shift ball in the throttle body had moved and wedged itself between the body and plate... don't know how and why all this happened at once but needless to say I put some money into build number 2 so I wouldnt have any of these issues again!