tranny id?

[mnz28]

Hello, I was wondering if anyone can tell me what tranny I have in my 87 blazer? I know it has the overdrive, the motor is the 350 tbi.

[WarWagon454]

[WarWagon454]

Also- you can look at your RPO codes inside the glovebox.

I know that MD8 is thm700r4 and i'm pretty sure that M40 is th400.

thanks for lettin me answer this one! I'm new but i'm not that dumb. Peace

[mnz28]

Im gonna assume that its either a 700r4 or a 4L80e as it has the overdrive. Im more of a 2nd gen camaro guy and I use my blazer as a snowplow and a winter vehicle. I owned a 1972 Blazer that I needed to get rid of as the body was beyond repair. Im looking for a 72 blazer shell to possably place on the 87 chassis. Like I said im not very knowldgable on the blazer but if you have a 2nd gen camaro question I just may have the answer for you. Thank you for replying as it gives me some ideas on how to identify it. I think I will try the glove box and see what it says.

[gangforward]

Originally Posted by WarWagon454

Also- you can look at your RPO codes inside the glovebox.

I know that MD8 is thm700r4 and i'm pretty sure that M40 is th400.

thanks for lettin me answer this one! I'm new but i'm not that dumb. Peace

Got a source to Decode the RPO codes?

TIA!

[kevinr1970]

Originally Posted by mnz28

Im gonna assume that its either a 700r4 or a 4L80e as it has the overdrive.

The 4l80 style transmission didn't start until I was told '92. But I have seen a Navy surplus '89-91 2wd 1ton crew cab that had an OD tranny and was told it was one of the first 4l80's.
I'm not 100% positive but I don't think any of the old body style Blazers or Suburbans came with the 4l80, only the 700's. Not 100% but if I'm wrong someone will chime in and correct me. Then we'll both know?!?
Now this isn't to say that someone didn't swap a newer tranny for a blown 700
somewhere along the line. But I think the new body trucks/Blazers/Suburbans had the front drive shaft on the driver side where as the older trucks had them on the passenger side. More likely with a 2wd then a 4wd?

[extd56]

1991 Suburbans 3/4 ton had a 4L80E in them, I have taken apart 3 of them and they all had them.

[edman87]

No k5 that I am aware of ever had a 4l series tranny. If it has OD, it is a 700r4.
As for the plow, don't plan on pushing the plow with anything with a 700r4 or towing with it either. That is unless you have it built right. They are ok for street driving and nothing else in stock form, they will do the chores, but won't lkast unless built-up.

[Captkaos]

Originally Posted by edman87

No k5 that I am aware of ever had a 4l series tranny. If it has OD, it is a 700r4.

Just to Clarify, the 4L60 IS a 700R4, and was designated as such starting in 1990 (nothing changed but the naming) = 4-speeds, Longitudinally positioned, 6000 lbs. GVW)

4L60-E = 4-speeds, Longitudinally positioned, 6000 lbs. GVW, Electronically controlled.

There are 2 version of the 4L60-E Pre- (93-96) which was the 700R4/4L60 with electronic control and Post (97-up) which was a completely redesigned case.

The 4L80E, however never came in a 1/2T trucks other than the 91-93 454SS.

[edman87]

Sorry, I was referring to 4l60e. My bad. I was thinking the kept the 700r4 name in that body style through 91.

[kevinr1970]

Very informative!

Originally Posted by Captkaos

Just to Clarify, the 4L60 IS a 700R4, and was designated as such starting in 1990 (nothing changed but the naming) = 4-speeds, Longitudinally positioned, 6000 lbs. GVW)

4L60-E = 4-speeds, Longitudinally positioned, 6000 lbs. GVW, Electronically controlled.

There are 2 version of the 4L60-E Pre- (93-96) which was the 700R4/4L60 with electronic control and Post (97-up) which was a completely redesigned case.

The 4L80E, however never came in a 1/2T trucks other than the 91-93 454SS.

[edman87]

BTW, how can those gross ratings be? A 4l80e came in 8600gvwr trucks. I am not doubting your info, just seems they tell you right on the label that gm automatics won't hold up to abuse. What was the 1/2 to gvwr in the 90's? 7200?

[Captkaos]

4L60 was rated based on 100K miles, from what I gather, not brand new. It has been used on trucks up to 8600lbs, this is on FACTORY motors.

1/2T in our bodystyle were rated for 6100 GVW

GM has also stated that the Dextron III is lifetime trans fluid...

[mnz28]

Thank you guys, You have been very helpfull.

[edman87]

The other manufacturers are no better. Look at the e4od ford, it came in heavy duty trucks meant to tow, behind a diesel, yet would barely hold up to regular driving! I have experience with a couple of these. The same e4od that came in 1/2 ton 4x4 with a 302, was placed behind 1 ton diesels.