Blown 700r4

[imiceman44]

So I have never had a problem with my 700r4, it was rebuilt 34k miles ago, and when I got a leak in my radiator I changed it and topped off my transmission fluid.
Well I ran out of dex3 and I had some b&m trick shift fluid so I figured half a quart would not do much but it can't harm.
I drove it one day and I lost the transmission.
First it felt like it started in second, after 30 minutes it wouldn't upshift to overdrive, then I lost all gears except 1st and reverse.
Trying to park it to take another car, it wouldn't move in reverse

I let be all day and I started it and it went reverse and then 1st for a mile then I barely made it back.
Al of this happened in 60 miles total from the time I put the trick shift.
I read about it and it is not compatible with electronic transmissions. But the 700r4 is not.
Could it be just coincidence?
I have to take it apart to see what happened but it was too quick.
Oh and it's a 1989 in my suburban

 

[1-ton]

Sorry to hear about your trans, but do a Google search using the search term "blown 700R4", and you will get 100,000 hits.

Time to get in touch with Greg Ducato for a new 700R4. Better yet go to a 4L85E. Those are rated for 650 Ft Lb of torque in stock form.

 

[diesel4me]

I doubt the B&M trick shift killed it--I've read that stuff is basically Type F transmission fluid,which has been used in GM automatics by racers for years to firm up the shifts..(at least in Th350's and 400's)..

It might be the govenor gear stripped out--that would only let first and reverse work...bought my van cheap because of that..

It probably just decided to take a dump--most 700R4's fail that way..fine one minute,then all hell breaks loose,and the loss of overdrive is a common symptom....something probably failed and its just a coincidence it happened after you topped the fluid off..wont hurt to check the govenor first though..

 

[imiceman44]

Sorry to hear about your trans, but do a Google search using the search term "blown 700R4", and you will get 100,000 hits.

Time to get in touch with Greg Ducato for a new 700R4. Better yet go to a 4L85E. Those are rated for 650 Ft Lb of torque in stock form.

Oh I have a 4l80e and a 454tbi waiting for this to happen so I can put them in.
I just never had a failure that quick.
And I will be opening it up and fixing it myself.

 

[imiceman44]

I doubt the B&M trick shift killed it--I've read that stuff is basically Type F transmission fluid,which has been used in GM automatics by racers for years to firm up the shifts..(at least in Th350's and 400's)..

It might be the govenor gear stripped out--that would only let first and reverse work...bought my van cheap because of that..

It probably just decided to take a dump--most 700R4's fail that way..fine one minute,then all hell breaks loose,and the loss of overdrive is a common symptom....something probably failed and its just a coincidence it happened after you topped the fluid off..wont hurt to check the govenor first though..

I will check the governor because some of the behavior was related.

 

[1-ton]

Oh I have a 4l80e and a 454tbi waiting for this to happen so I can put them in.
I just never had a failure that quick.
And I will be opening it up and fixing it myself.

I was reading a GM Performance catalog I got from the GM Performance booth at the NHRA drag races a couple of weeks ago, and I was amazed to find that the catalog listed the 4L80E (like I have in my crew cab) its rated max capacity is 400 Ft Lb of torque while the 4L85E its max rated capacity is 650 Ft Lb of torque.

 

[Greg Ducato]

The Trick Shift didn't kill it but is an odd coincidence that it failed that way, you can use a quart of motor oil in the system and it wouldn't make much difference on the older transmissions such as the 700R4. These and the 4L60E are like the governor bomb G80 10 bolt. You hear people with 250K miles on 35's that have never broken one and then there is the guy with the mall crawler on 31's that didn't make it to 75 thousand miles. They are not "husky" transmissions

 

[Blue85]

So have you drained the fluid (and looked at it) and refilled?

Isn't it possible being low on fluid is the initial symptom? Something must have prompted you to add fluid.

 

[imiceman44]

So have you drained the fluid (and looked at it) and refilled?

Isn't it possible being low on fluid is the initial symptom? Something must have prompted you to add fluid.

I changed radiator and refilled the transmission fluid that was lost in the process.
I don't have time for it now but when I get the chance I am opening it up and checking

 

[6.2Blazer]

I agree with the above statements.....likely just coincidence in regards to the Trickshift fluid, especially if only running 1/2 quart of it. I would be more concerned about the radiator replacement, such as the new one having some sort of issue with trans cooler. Was it a new radiator or a used one? I could see either have a plugged up trans cooler or having some type of debris in it. Of course the trans going out after a radiator replacement could have also been a coincidence also.

You stated the rebuilt trans only had 34k on it. How many miles did the original trans have on it before needing rebuilt? Seems pretty common for people to go 100k+ miles on the original transmission and then the "rebuilt" trans only lasts 15k-30k. Then everybody jumps on the bandwagon of how crappy the trans is because they only last 15k-30k and never consider that maybe it wasn't rebuilt correctly or the cooler lines weren't flushed out and filled the new trans with debris.

 

[Babaganoosh]

The Trick Shift didn't kill it but is an odd coincidence that it failed that way, you can use a quart of motor oil in the system and it wouldn't make much difference on the older transmissions such as the 700R4. These and the 4L60E are like the governor bomb G80 10 bolt. You hear people with 250K miles on 35's that have never broken one and then there is the guy with the mall crawler on 31's that didn't make it to 75 thousand miles. They are not "husky" transmissions

I was hoping the mall crawler statement was my truck. I got 90 miles total out of 3 transmissions.

Thankfully I had your shop build me the one I'm not scared to drive down the highway, already planning the 3rd trip.

 

[Blue85]

Well if the new rad could leak coolant into the transmission lines, that would explain the sudden death. That should show up even on the dipstick, though.

 

[Greg Ducato]

I was hoping the mall crawler statement was my truck. I got 90 miles total out of 3 transmissions.

Thankfully I had your shop build me the one I'm not scared to drive down the highway, already planning the 3rd trip.

I have seen your driving videos, that's the kind of shit that keeps a transmission builder up at night

 

[frankin5]

I have seen your driving videos, that's the kind of shit that keeps a transmission builder up at night

You should have charged him triple for your warranty.

 

[Greg Ducato]

Had I only known

 

[imiceman44]

I agree with the above statements.....likely just coincidence in regards to the Trickshift fluid, especially if only running 1/2 quart of it. I would be more concerned about the radiator replacement, such as the new one having some sort of issue with trans cooler. Was it a new radiator or a used one? I could see either have a plugged up trans cooler or having some type of debris in it. Of course the trans going out after a radiator replacement could have also been a coincidence also.

You stated the rebuilt trans only had 34k on it. How many miles did the original trans have on it before needing rebuilt? Seems pretty common for people to go 100k+ miles on the original transmission and then the "rebuilt" trans only lasts 15k-30k. Then everybody jumps on the bandwagon of how crappy the trans is because they only last 15k-30k and never consider that maybe it wasn't rebuilt correctly or the cooler lines weren't flushed out and filled the new trans with debris.

I didn't not think of this, you might be right.
The radiator was used and I found out now that the transmission in that truck had failed so there might have been some debris in the cooler.

 

[1-ton]

I didn't not think of this, you might be right.
The radiator was used and I found out now that the transmission in that truck had failed so there might have been some debris in the cooler.

I learned a long time ago to never run my transmission cooling lines through the radiator. It is too risky. I just run my transmission cooler lines straight into a decent size trans cooler.

 

[imiceman44]

I learned a long time ago to never run my transmission cooling lines through the radiator. It is too risky. I just run my transmission cooler lines straight into a decent size trans cooler.

I did that on all my wheelers but this is a stock suburban didn't want to reinvent the wheel

 

[Babaganoosh]

Had I only known

Hey I said up front I like to use every bit of the engine it has haha.

 

[diesel4me]

We used to sell WIX "in-line" universal filters for automatics at the parts stores--many shops would install one after installing a used or rebuilt transmission once they flushed the cooler out in the radiator with brake cleaner and compressed air to ensure no debris left behind from the failed transmission would get into the "new" one..

This photo is of one made by ATP,but the WIX ones look similar--I found one of the WIX ones had been installed on my Suburban,the previous owner told me when I bought it the 700R4 was failing,it didn't want to go into overdrive most of the time,and reverse sometimes wouldn't work after you drove it some distance..

--he did drop the pan on it,said it looked like road tar inside for fluid,all he did was spray it all clean with brake cleaner,and blow it off with the air hose,and put the pan right back on,refilled it with dexron atf and a quart of Lucas transmision treatment,which didn't really change anything..I bet he put that in-line filter on it too,but he didn't say so..I wonder if that filter could be plugging up,but chances are the 700r4 is on its way out ..