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Need help 93 suburban- tranny

05-18-2007, 04:16 PM
I bought a 93 gmc suburban 5.7 l - 2wd automatic , Its ran fine for about six months, Then it started to shift hard out of first gear. I had speedlube change the transmission filter and fluid- they told me i shouldnt that it may cause problems but i had it done anyway. It shifted fine for about a month, Then when i first took off it felt like it was in nuetral - then it would catch and shift ok when shifting to second and drive. I added a bottle of lucas transmission fix but has not helped- now the other day i get up to go to work and it will not move in reverse at all. I checked the fluid and it seems about a quart too high(because of the lucus fluid i added) but i doubt that would of caused it? Is the transmission definatelly bad- or is there anything i can check????

I have a buddy at work who says he has a 700r4 tranny that he would sell me for $250. Is that the tranny i need? He said it came out of a mid 90's chevy truck.

Any help will be greatlly appreciated.

05-18-2007, 04:28 PM
You are right the trans is bad especially when you loose reverse You probably have a 4l60e which does not interchange to a 700r4..

05-18-2007, 04:47 PM
so what is the exact tranny i need to be looking for? Thanks for the quick reply by the way! I appreciate it

05-18-2007, 05:36 PM
You sound like you are a victim of a reaction sun shell failure. This is common on these transmissions. The pan should look rectangular - if you see a wiring harness coming out of the PASSENGER side of the transmission, with a lot of wiring, and NO wires on the DRIVER side, you have a 4L60E. If you have a 3-wire harness coming from the DRIVER side and a TV cable, you have a 4L60 - no E - also called TH700R4.

A reaction sun shell failure results in the failure of gears reverse, 2nd and 4th (the hard shift out of first is probably direct to 3rd).

05-18-2007, 05:51 PM
well i just went outside and tried it again- Its driving in all gears- but its slipping bad when in reverse and when you first take off. The fluid looks good but has a strong smell to it so i dunno. I noticed when i checked the fluid that it was about 1/4'' above the check hot line on the dipstick, and this was with the motor/tranny cold. So would having too much fluid in the tranny cause problems?

Sorry for rambling on but I really need to get this thing running decent.

05-18-2007, 07:05 PM

05-18-2007, 09:41 PM
Sounds to me like the fwd clutches are slipping. They are applied in reverse and 1st.

Sometimes this can be caused by a worn forward accumulator pin. See


05-23-2007, 02:59 PM
ok guys heres the latest...
Its been driving ok- but in the morning when the motor/tranny is cold it slips the worst- other than that it just slips alittle taking off and alittle in reverse.

I got under the truck and found that on the driver side at the tail end of the tranny there is a thin plug with 2 wires. And on the very top of the tranny / on the pass side i believe.... there is a big round plug- cant tell how many wires cause theres a plastic shroud or loom around the wires....

I dont know what to do.... I dont have alot of money right now- but this is my only vehicle right now. Should i drive it till it goes out?
Anyone have any ideas?
Theres a transmission specialist here that i guess drives your car and tells you what they think is wrong for free.
But i want to sound like i know what im talking about so they dont try n get over on me..... What should i tell them that i think is wrong with the tranny? Hopefully its something that can be fixed for under a couple hundred bucks- and not need the whole tranny rebuilt

thanx guys i really appreciate it!!!

05-23-2007, 06:42 PM
Just driving it for free is not a proper test.
The only way anybody can know what is bad on it is proper testing.
And do not try or worry about being able to tell the mechanic what is bad.
That is his job to check it out and tell you what is bad.
But here is a good tip on finding a good repair shop.
Check around Ask around
Word of mouth.
Family friends coworkers neighbors business people and delivery people.
Mailmen and parcel delivery people get around and notice a lot of stuff.
Even a good parts house knows what shops are good and not good.
Chamber of commerce and better business bureau and city hall.
If you find a good referral to a repair shop go look them over and talk to them.
Look for a clean looking busy place with nice people running it.
Ask a few questions and ask about their qualifications and training.
Not all places have trained tech/mechanics.
If they do not find a place that does.
Even all dealers do not have all trained techs/mechanics.
Good luck

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