98 C/K 4X4 Automatic Tranny Problem

when pulling any small or big trailer with this truck, the tranny hits really hard when going into a higher gear. tranny does not hit hard for the first few miles
it does take a few miles before this starts to happen. this only occurs when towing a trailer.
when i turn off the truck and wait for a few minutes the tranny works fine for a few miles then the hard shifting begins again.
the farther i go on the freeway with a trailer, the harder the tranny hits when going up a gear.

the last time i was towing a 6x8 trailer with a dirt bike, tranny fluid went every where. truck still shifted, just oil every where. truck now smells of burnt fluid.
put tranny fluid back in and now there is no leaking (not towing anything). truck runs and shifts good. truck has started to make a low wobble noise lately also.

felt a really bad vibration in a turn the other day, vibration also happened when shifting into gear after the turn, this vibration has only happened once.

this truck has a 1500 motor

anyway, hoping some may know what is going on with this tranny.
will answer any question you may have.

nice site, looking forward to chatting with you all.

hard shifting is because the PCM knows tranny is slipping .. on shutdown it all resets.

so why is this happening when towing only ??? this maybe due to you operating in OD when towing. never use OD use 3rd gear . this prevents over heating and then slippage.

the tranny fluid to use must be dexron VI. this is now the GM approved fluid. GM does not use this spec anymore in any vehicle. also will not do any warranty coverage if this dexron III is used. many tranny shops still use this damaging fluid .

I would drop pan replace filter, clean up the mess in the pan install dexron VI and add a tranny cooler in front of the ac condenser. that should do it.

thanks for the info j cAT.
we kinda thought electronics were involved do to the tranny not hard shifting after a restart. just did not know for sure.

with the leak and smell of burnt fluid, i wanted to change tranny oil/filter.
still do not know where the fluid came from.

really wondering about how much damage was caused by this. so i will be taking the truck to a shop to check things out.

thanks again for the info. :ylsuper: i will definitely not tow with the truck in OD.
will also look into putting a tranny cooler in.

what happened which is quite common is the tranny fluid boiled and bubbled out the tranny vent IMO....

pan drop filter change then do the fluid exchange method at the radiator tranny fluid line.takes 12 qts to do. this will remove the bad fluid engine on in neutral . as 1 qt comes out you add 1 qt in the dip stick bore.

dexron III turns to acid when over heated so only use dexron VI ....

since you tow add the tranny cooler when you do the fluid exchange method since that line will be disconnected .. easy to install a tranny cooler on these trucks save your transmission.

started looking at coolers today, they are some what cheap, will put one in.

OD seems to be getting worse, even without towing. OD hit hard once today, i put it in third, ran good.
i drove in 3rd today, seemed fine.

looks like i will be getting a fluid change very soon. do not want acid in the tranny.

still worried about the noise this thing is making. noise is getting bad when in OD, not so bad in 3rd.
this noise started before the fluid burned up.

thanks again for the advise

could be the torque converter got some tranny particles in it with the over heating . fluid change may help it or it may be damaged . hard to say until it is serviced .

when checking the fluid use a white cloth see if it has particles .. use a magnifier.

going to service soon, will look for particles. have not had time to work on it, cause of work. have not been driven the truck either.

will probably take it to a mechanic. thinking it would only cost about 100.00 to get flush done. this way the flush will get done correctly.

thanks again for the info j cAT
i will keep you updated

Good luck with having a "professional" do it right. They're likely to flush the FLUID and never drop the pan to change the filter. It has been my experience that the guy doing the flush is the newest, most-junior member of the service team.

"I" would never put expensive fluid into a transmission that had the potential for needing an overhaul, especially when the trans wasn't spec'd for the expensive fluid in the first place. In my driveway, that'd get Dex/Merc (Dexron III substitute) until I knew for sure that the trans didn't need to come out for rebuilding.

went to have a flush, they said they do not replace filter. did not do the fluid change.
now just looking to get a inspection and so on. :frown:

thanks for the reply Schurkey

went to have a flush, they said they do not replace filter. did not do the fluid change.
now just looking to get a inspection and so on. :frown:

thanks for the reply Schurkey

remember I said pan drop filter replace and the fluid exchange ..
you never do a flush which means a machine is hooked up then they do not drop pan because that takes more time and this is a damaging service. the fluid exchange after the pan drop filter replacing/cleaning is what you need since the fluid got cooked. .

you must use dexron VI since that is NOW the approved GM fluid. do not use dexron III ....

went to have a flush, they said they do not replace filter. did not do the fluid change.
now just looking to get a inspection and so on. :frown:

thanks for the reply Schurkey


The flush gets all the crap to get flowing around and then damages the torque converter.. this method is OK on some vehicles manufactured but NOT GM vehicles esp.... a 4L60 tranny....clutch material is very high on these so no force fluid activity is allowed ..

on trucks like yours some put a tranny filter in line with the cooler. this filter has a magnet in it. many that have had issues with shifting due to being old have found this filter to work very good.. back when GM made Saturn vehicles they did come with this filter from factory .. fluid lasted much longer...

i thought the flush came with a filter/fluid change.
thought they would flushed the tranny then, put in new filter and fluid.
maybe going to a quick oil change place, was a bad idea!

just taking my chances with a shop, hoping sat.
its to cold and this thing needs some kind of adjustment or something. vibrating is getting worse. :banghead:

thanks again j cAT.

My opinion is that you really need a new tranny! Fluid & filter changes or fluid transfusions most likely will not cure your tranny issues.

Good Luck to you.

i thought the flush came with a filter/fluid change.
thought they would flushed the tranny then, put in new filter and fluid.
maybe going to a quick oil change place, was a bad idea!
Quick-Change artists are often crooks. Spiffy Lube can K-M-A.

I drop the pan, remove (and inspect) the bulk of the "crap" and debris. Seeing the debris, I have a feeling for the general condition of the transmission--metal pieces are never good, large chunks of burnt friction material are never good, but fine grey powder--in reasonable amounts--is pretty normal. I replace the filter which is going to be contaminated with crap and debris, reinstall the pan having gotten rid of ~5 quarts of contaminated fluid, and THEN flush the rest of the contaminated fluid out knowing that when I'm done, nothing but clean fluid has been put into the pan; so extremely little contaminated fluid remains in the transmission--only the residual oil that was in the geartrain and bushings, trapped in the clutch drums or in some of the transmission fluid circuits--ounces, not quarts.

Flushing then dropping the pan means that the new fluid comes in contact with all the debris at the bottom of the pan; and when you drop the pan, you're dropping the new fluid which then has to be replaced with more new fluid.

I'll say it again--no way in hell do I pay for synthetic Dexron VI when the transmission came from GM set-up for inexpensive Dexron III; and the transmission may be terminally wounded anyway so it would all be wasted when the trans comes out for rebuilding.

AFTER the transmission has been overhauled...I could see installing Dex VI.

In truth, I'm fairly satisfied with Dex/Merc (Dexron III substitute) as I've never had a single transmission problem I can blame on "defective acidic fluid". None of my vehicles are newer than 2003; so all of them came factory-filled with Dex III. Again, if I ever buy a newer vehicle, I suppose I'll have to stock-up on the newer fluid.

what some have done with a contaminated tranny is they used dexron III as a flush fluid to remove the antifreeze that got to the tranny from bad radiator . then after all the bad fluid came out [much cheaper flush fluid] they installed the dexron VI..........

thanks again to j cAT, 777stickman, Schurkey for the reply's.

we took the truck to a transmission shop. they said the torque converter is bad.
with that said, we will be rebuilding this tranny. we will also be putting dexron VI, thanks for the tip j cAT.

not sure how this rebuild will go but, we are looking on line and so on for tranny rebuild kits, complete rebuilt trannys and so on.
we would really like to just switch out this old tranny for a rebuilt tranny.

one question, how can i tell if this tranny is a 700r4

any suggestions would be welcome.
thanks again

A TH700-R4 has a TV cable at the throttle body linkage, no shift solenoids, and would not very likely be installed in a 1994.

i would put a pic up but this site gallery sign up/attachments does not work? photo bucket did not work also.
it is amazing what a pain in the butt the net has become. :banghead:

a 1998 gm truck comes with the 4l60 for that model year. now to install a 700r4 in it that would not make any sense since those transmissions suck and the cost and work to make it work would be insane . look at the connector to the transmission see if it has a lot of wires to it if so its a 4l60 .

i was told this might be a 700r4. i am looking at the 4l60 now.
so here are some pics, maybe this can help someone know for sure what tranny it is. :banghead:

thanks again

http://oi68.tinypic.com/2dkbadl.jpg

http://oi63.tinypic.com/2uzdq2t.jpg

http://oi65.tinypic.com/1zoc848.jpg

http://oi67.tinypic.com/293yfdh.jpg

http://oi63.tinypic.com/143ndcn.jpg

If that is the original pan, it is a 4L60E. The TH700-R4 had either a flat bottom pan or a ridged bottom, not the stepped bottom as the 4L60 used. The indentation for a drain plug was also not on the 700-R4.

Moreover, the bolt on bellhousing is a 4L60 feature.

The first photo also shows the range selector switch, which is not a 700-R4 feature.

thanks, we are now looking for a 4L60E.

thanks, we are now looking for a 4L60E.

that pan is the deep pan on the 4l60 . also as was mentioned this does not have a down shift detente cable which the 700R4 must have. tranny shop that looked at this I would not use , most likely not a GM service shop or newbies in the business. just be sure the connector is the same on the replacement tranny because if its different it is the wrong tranny.

When searching for a replacement, be aware that not all model years will be compatible.

The solenoid arrangement and the solenoid coil resistances varied across the model years. Your PCM would likely generate a fault code and/or not shift the transmission if it detects a solenoid out of the correct resistance range.

It should be safe to use a unit from a 1997-2003 but verify that with the interchange guide at you local salvage yard. Earlier units had different solenoid resistances and different arrangements. For example, the 1993-94 units used an 11 pin connector. The 1995 units used a 12 pin connector. Later units used a 16 pin connector. The pump bodies and porting were different, the TCC scheme was different, and the 3-2 shift and downshift schemes were different. Installing the wrong trans to the wrong PCM can not only generate codes, but can cause long term problems with overheating, shift problems, and clutch failures.

To complicate matters, the speedo connection may be on the wrong side, and transfer case mounting may vary.

Again, verify the replacement with an interchange guide.

once again, great advise and it is very much appreciated.

we are going to have this tranny rebuilt. looking to get a new torque converter and a rebuild kit.
this seems to be the cheapest way to go. this will still cost me about $1000.00, still better than $1500.00 to $2000.00.

will keep you all updated, thanks again

we are going to have this tranny rebuilt. looking to get a new torque converter and a rebuild kit.
this seems to be the cheapest way to go. this will still cost me about $1000.00, still better than $1500.00 to $2000.00.
$1000? I'd have figured double that.

The 700 in my '88 K1500 cost $1600 back in 2001 or thereabouts. I did need some hard-parts--a planetary set has completely wiped-out it's roller bearings and put metal shavings EVERYWHERE. Of course, it got a sun-shell and other hard-parts, too. This also includes the R&R labor and a TransGo shift-kit, in addition to the rebuild.

once again, great advise and it is very much appreciated.

we are going to have this tranny rebuilt. looking to get a new torque converter and a rebuild kit.
this seems to be the cheapest way to go. this will still cost me about $1000.00, still better than $1500.00 to $2000.00.

will keep you all updated, thanks again

with a new torque converter and $1000 to rebuild it , that is cheap. I would install a in line tranny magnetic fluid filter at the radiator line up front. then after some use check it out for metal debris . the magnet filters work great to capture all the crap from the old damage and whatever got loosened up from fixing. these are cheap insurance ..

That's about right for a full rebuild. I've done several for less than $250 in parts, including all the shims, frictions, separator plate, pump vanes and slide, and moderate updates. More than a few small parts will start ratcheting up the cost, but it's pretty hard to spend more than $750 in parts unless you bolt on a factory new valve body and numerous other parts. A good, 30,000 mile guaranteed GM factory reman converter can be had for about $125 exchange price, and is worth every cent on a trans with over 100K miles.

ok so, my buddy took the tranny off the truck and realized the torque converter was hooked to the flywheel in some way?
i guess the oil pan has to be taken off to get to/remove the torque converter. any of you guys have clue what this is about?
he said this set up was only done for 3 years, then chevy went back to having a dust cover that made this torque converter easy to remove.
so much for saving some money :banghead:

thanks for looking

so looks like my buddy was just worried about nothing? anyway, hopefully i will have more news soon

If he pulled the transmission off without removing the torque converter-to-flyweel bolts, somebody had better inspect the trans pump and converter bushing REALLY CLOSELY.

I would be reluctant to let him work on it any more.

so ol dude got the tranny out, finaly.
we took it to the tranny guy who did a complete rebuild. charge 900 with new pump, torque converter and rebuild kit.
we took the tranny back to the dude to put back in the truck. turns out he did not have the torque converter seeded correctly and tore up the pump.
tranny is back at the tranny shop. :banghead:

one month later i am just about to go nutts. so much for saving money.
looking for the good in this, just have not found any yet. anyway, thanks again for all the advice. will post when things are complete

so ol dude got the tranny out, finaly.
we took it to the tranny guy who did a complete rebuild. charge 900 with new pump, torque converter and rebuild kit.
we took the tranny back to the dude to put back in the truck. turns out he did not have the torque converter seeded correctly and tore up the pump.
tranny is back at the tranny shop. :banghead:

one month later i am just about to go nutts. so much for saving money.
looking for the good in this, just have not found any yet. anyway, thanks again for all the advice. will post when things are complete

If he pulled the transmission off without removing the torque converter-to-flyweel bolts, somebody had better inspect the trans pump and converter bushing REALLY CLOSELY.


I would be reluctant to let him work on it any more.
For fukk sakes, do not allow that moron to touch your vehicle again. The guy has sh!t for brains.

At least he's paying for the damage he did to your transmission. That won't cost you anything but time.

Don't get me started on what "seeds" he was sprinkling on the torque converter.

Don't get me started on what "seeds" he was sprinkling on the torque converter.

oh well, cant blame that on spell check.

well finally got the truck back. not happy, but it is done. :banghead:
next time i will let a pro do all the work.
anyway, thanks to all again.

looking forward to putting in new gas shocks on the trucks cap.
i have a leak coming from the valve covers.
so you will hear more from me. :crying:

thanks again all

well finally got the truck back. not happy, but it is done. :banghead:
next time i will let a pro do all the work.
anyway, thanks to all again.

looking forward to putting in new gas shocks on the trucks cap.
i have a leak coming from the valve covers.
so you will hear more from me. :crying:

thanks again all

so with your comment sounds like you messed up. what did you do wrong ? best to learn from the mistakes from others than your own .. even if its really stupid stuff..

so with your comment sounds like you messed up. what did you do wrong ? best to learn from the mistakes from others than your own .. even if its really stupid stuff..

did mess up but, did learn a lot from the guys mistake. found a good tranny guy?