Transmission trouble

[stantjeeper85]

My tranny isnt shifting the way it is suppose to. With the way the burban is geared, in overdrive it is suppose to shift around 1800 rpms. But right now it is shifting between 2500-3000 rpms (which is alot considering the tach only goes to 4000). its been off and on like this for a little over a week and now it is starting to have trouble shifting into 1st gear when i take off from a dead stop. Ive been told its a fluid issue and that something may be clogging the throttle valve. first, WHAT is a throttle valve? And what can be done to fix this issue? Im going to change the tranny fluid this weekend. Im guessing this is a 700r4.

[Robyn]

Drop the pan and see whats in there.
Could be a dirty filter and dirty oil.

If you find large amount of shiny stuff in the pan there is likely greater issues.

Make sure your throttle pressure cable is working right.

The TV circuit is run by the TV cable that hooks up to the IP

What year is the truck???

Robyn

[stantjeeper85]

its an 89. previous owner rebuilt the tranny a few thousand miles before i bought it and ive only put a few thousand miles on it since i bought it.

When you say "drop the pan" what pan exactly are you talking about? For the tranny??? Ive done very little tranny work in my time (changed the fluid in an old jeep of mine) but with proper instruction I can do anything ...

[Robyn]

YESSSSSSSSS Tranny pan :)

Drop the pan and carefully dump the oil out.
Look for sparkely crap in the bottom. (shavings, metal)

There are nice manuals avaiable (Modest price) for auto trannies and are model specific.

These books are very helpful (Unlike the one size fits all books)

I did my first tranny O'Haul back in the 70's with one of these and having never seen the inside of an auto before.

Was a snap, had it all out, done and back together in a weekend.

Good luck

Robyn

[stantjeeper85]

okay so i changed the fluid and NO luck. I did drop the pan to see what was going on under there and did NOT find any shiny little pieces of metal (phew). The oil WAS dirty though. A disgusting dark brown and smelled burnt. The fluid i put in was a red colored synthetic blend. Took it for a test drive and still shifted into each gear at about 2500 rpms. It did NOT shift into overdrive at all. The only difference i noticed was that it didnt shift as hard.

So whats the deal!?

[Robyn]

BURNT :eek:


Tranny shot

Hate to be the harbinger of sad news but, the burnt smell is from clutch lining thats gone away.


No 4th gear is likely a result of a burnt 2-4 band or a 3-4 clutch.


No real way to tell other than rip it apart.


A 700R4 is not a bad tranny but, there are a lot of things that need attention to detail when rebuilding.


The biggest thing is the addition of a good shift kit.
I prefer the Transgo "Dash 2-3" kit and I always set everything on the KILL settings ;)


This kit also makes many recommendations as to other parts that should be replaced and or upgraded while the box is apart.



Clutch and band lining is basically a paper substance, that when soaked with oil provides the frictional clutch surface.


When there is slippage the paper gets hot and burns.
The acrid, nasty smell and dark color of the oil is the tell tale sign.


My only suggestion is to plan on yanking the box out and spreading it out on the bench.


There is no quick fix at this juncture.


Secret for a 700R to survive
Do all the upgrades that are recommended. Always do a shift kit.
A 700R has very tiny parts inside as compared to a 4L80 or a TH400
The clutch drum is aluminum and the clutches are very small.

The number of lined plates and steels needs to be increased in the 3-4 clutch to the max that will fit. (Kits explain)
The sun shell needs to be replaced with a "BEAST" or similar.
Sprags need to be upgraded.
Input drum needs to be replaced with a HD reinforced unit.
2-4 band servo needs to be upgraded
A few valves need to be changed as well.
2-4 band needs to be a HD unit

Oil pump needs to be the 13 vane unit.

Make sure the TV circuit is adjusted absolutely correct or the sucker will go away.

This may seem like a lot of work but, if you want the little 700R to live, this is what it takes to keep them healthy for any length of time.

Been into several, and when done right, they work sweet.
Seen many fried ones too.

In a light car application they are not too bad from the OEM.
Pickups, Burbs and such will task them to the limit, especially if you try and tow with them.

The diesels literally rip them apart in stock OEM config.

The early ones (82-85) would split the input shaft lengthwise and explode the tranny all in one quick bang.

The later units ("K" Case) are good core to use.
They have two valve bodies and several other desirable things.
Good starting point to build on

The governor must be for a diesel if using just any "K" case tranny.

Car 700R's have small clutch packs and are unsuitable for a 4X4, pickup or Burbs



Keep us posted and we will help where we can.


Robyn

[stantjeeper85]

Wish I had read this sooner, although Im not sure it wouldve made a difference. After the weekend was over the tranny started shifting better. I figure maybe it took some time for the new oil to work its way through the tranny. So I drive on it. At times its still sketchy but mostly is okay, even shifts into overdrive, until last night. Driving home down the highway and no overdrive. Is like this for 15 miles when finally the tranny gives out, "slips" out of gear, and no more forward motion. The truck slows to a dead stop. No gear works. Not even reverse. Had to get towed home.

So I guess im looking at needing a new tranny or having to rebuild this one? Kinda frustrating considering the previous owner claims to have rebuilt it 3k miles ago.

How do I tell for sure what tranny I have?

[DmaxMaverick]

Wish I had read this sooner, although Im not sure it wouldve made a difference. After the weekend was over the tranny started shifting better. I figure maybe it took some time for the new oil to work its way through the tranny. So I drive on it. At times its still sketchy but mostly is okay, even shifts into overdrive, until last night. Driving home down the highway and no overdrive. Is like this for 15 miles when finally the tranny gives out, "slips" out of gear, and no more forward motion. The truck slows to a dead stop. No gear works. Not even reverse. Had to get towed home.

So I guess im looking at needing a new tranny or having to rebuild this one? Kinda frustrating considering the previous owner claims to have rebuilt it 3k miles ago.

How do I tell for sure what tranny I have?

Sounds like it's shot. Typical symptoms.

An 89 with OD is a TH700R4. Do yourself a favor and follow Robyn's advice on the rebuild. Be sure it is at least the correct case for your year model. It should have a large "K" on the right side of the case. If it doesn't have the "K", it's been swapped out with an earlier model at some point. Many tranny exchange rebuilders mix/match them, and most folks don't know to check for this.

[stantjeeper85]

I have alot of experience in general maintenance of trucks. But i have no experience in working on transmissions. (of course, I once said that in regards to engines, but with the help of a good haynes manual i was able to rebuild the engine in an old jeep of mine). But engines and transmissions are not the same things unfortunatley. Would it be wiser to take it to a place like AAMCO and have them fix the tranny? What cost would I be looking at if i went that route? What cost would I be looking at if I tried to rebuild it myself? is it possible or feasible to consider switching out to 4L80 or a TH400
? are these better/stronger trannys? What about converting to a manual?

[rustyk]

NOT a place like AAMCO - you're far better off with a local shop, hopefully one with an ugly, near toothless guy with scraggly hair and a name on his shirt like "Bud".

My motorhome had an AAMCO rebuild (4L80E), which I knew when I bought it - and factored in the price of a real rebuild. That came last year, and I had it done by a local guy (who I already knew) and had only HD Borg-Warner parts used.

IMHO, AAMCO builds to a price point. Local builders basically say, "I don't ever want to see that one again!" because the local mechanics don't want to eat the labor on a warranty claim.

[stantjeeper85]

Well, Aamco already picked it up last night. The pick up was free of charge and theyre gonna diagnose the problem free of charge and call me before they begin any repairs. Im just gonna wait and see what they say. My dad's 85 6.2 burban tranny was rebuilt by Aamco and it never had any problems after that (same shop as where mines at).

[Robyn]

Rusty

I know the place, we have one here too. Called Bubbas tranny shop :eek:

Those little hole in the wall places with barely enough room in the bay between piles of crap for your rig to fit on the hoist are the cream of the crop.

The Kids just had their 4L80 done at a little shop here in Newberg.

Couple steps up from the "Buds" but the fella's there are darned good and know what they are doing.

Cost about $2K for the 4L80 in the kid's 99 GMC 2500 4x4

They paid for the parts and I did some trading with the owner of the shop for the labor (He likes Gun toys) :D

All parties came away happy on this one.

Ammco Hmmmm not my first choice BUTTTTTTTTT any port in a storm I guess.

The biggy is, does the tech know what the heck he is doing???

Even the best shops can have garbage go out the door if the tech is sloppy.

You must be very anal when working in these auto loaders as there are so many places that can bite you if your not careful.
.

Robyn

[rustyk]

Amen, Sista!

Although I had my 4L80E rebuilt by a guy named "Chris" (who names a Baby Transmission Builder, "Chris"?), but he was well-known to me, and despite over 25 years doing this, he:

(Sit down folks! Seriously!) CHECKS THE SHOP MANUAL ON EVERY STAGE OF EVERY TRANSMISSION, AND GOES THROUGH ABOUT 6-8 ROLLS OF PAPER TOWELS CLEANING HIS HANDS BETWEEN STEPS!

Which is probably why he gets a "come-back" about every five years.

I had my '87 Honda tranny rebuilt by Roger (who could well have been named Bud, except he was missing less than a dozen teeth). This was Roger's first Honda, and after he finished, it ran perfectly for over 200K miles.

But he KNEW ATs, and mentioned, "By the way, that thing failed (at 44K) because this part was installed backwards."

I agree the tech is the major element of the equation, but I doubt AAMCO is springing extra for premium parts.

[Robyn]

Talk about ANAL
6-8 rolls OMG :eek:

Clean hands type for sure.

Missy

[stantjeeper85]

Truck should be fixed later today. Aamco is installing Borg Warner parts. Ill let youo guys know how it goes.

[1984potato]

Mine is in dire need of a good look over. Originally built by Mike, the 700r4 expert at AAMCO. Governor weights were for gasoline (Robyn diagnosed the problem from thousands of miles away) and now I get some serious slippage when I mash the long skinny pedal. I wonder if the torque converter is also for a gasoline engine. Words of caution: WATCH THEM VERY CLOSELY!!!!!:( ASK LOTS OF QUESTIONS!!!!

The Diesel Page has helped me understand my truck to the point I haven't been on in a long time. Great job Guys & Gals! Fair warning-I'm back!

Haus.

[rustyk]

Truck should be fixed later today. Aamco is installing Borg Warner parts. Ill let youo guys know how it goes.

Now that's AMAZING! If they really do that (and aren't lying), you'll have a damned good tranny!

[Robyn]

Potato

The converters are very different from a 350 gasser to a diesel.

The converter used in the 400 was basically the same from the big block to the diesel.

The 700R4 was never used with a Big Block.

The 6.2 got the 700R but the 6.5 TD never saw one from the factory.

I have seen them used in that application BUTTTT this is a tad iffy at high power levels, unless the 700 has been well built.

The stall speed of the converter for a 350 gasser is far higher than for the 6.2.

You can simply swap the converter though. No biggy.

There are other parts in a 700R that are different on the diesel too.

The clutch packs usually have more plates.


Missy

[Edahall]

After having my 700R4 transmission rebuilt by a reputable shop for my 82 Suburban, I was driving down the highway at a high rate of speed and noticed that there was some slight slipping going on at high power levels in overdrive. I brought the Suburban back in and the owner/rebuilder had to increase the pressure. He was surprised that the little 6.2 could put out that much torque. Since then, I have put about 60k of hard miles without incident.