The transmission in my '98 Blazer is starting to give me some trouble. It feels like there's some slip, shifting is a little rough, though driveable, and my gas mileage is about 3-4 mpg worse on average. The check engine light went on and the error code seems to be P1870, which I guess indicates slippage.

I have about 120k on the Blazer now. My local shop says I need to rebuild or replace, but couldn't refer me to anyone reputable in the local area to do a rebuild. He told me he'd keep an eye out for a good deal on a replacement, but I've been looking at remanufactured stuff.

I've been looking at monstertransmissions.com. Is something this drastic called for? If so, does anyone have any experience buying from Monster? I'm specifically looking at one of these.

 

I had heard good things about Monster Transmissions up until recently. A friend of mine installed one about a year ago and it failed. They pulled some obscure requirement out of no where to say they were not liable and that the warranty was void.

A quick search for "P1870" turned up:
P1870 Explained

 

After digesting the P1870 search results, it sounds like it might not be unreasonable. The warranty story sucks. Your friend doesn't happen to reside in CA...?

The problem for me is that my Blazer is a DD, so if I'm going to have the transmission taken apart for any appreciable length of time, I'm not opposed to spending some $$ on a more solid fix, especially if I get some other performance benefit from it.

I saw that you had previously recommended MT, but now seems like there's reason to be cautious. Do you know of any of their competitors that you might recommend?

 

No, he resides about 20 minutes east of me in NY.

My recommendation would be to ask around for a competent mechanic that has rebuilt the 700R4/4L60/4L60E before and go that route. Having someone local to go back to if you have problems is MUCH better than dealing with someone a long way away.

Prior to this issue, I have heard a lot of good things about their transmissions and none of the people I had talked to had a problem. This one case of someone having a problem and getting tossed out on his butt makes me skeptical...

 

That does suck. I know my way around contracts, and I wouldn't have problems with court... except FL is a bit far for a $1600 part. But their treatment of your friend probably just cost them a sale. :-)

 

I had the same problem, turned out i had a pressure gasket leaking tranny fluid, check your fluid level after running it for like ten miles and leave it running while u check it. I just fixed it changed the fluid and filter and put in lucas tranny fix and it works perfect. I wouldnt keep driving it to avoid damage

 

It never hurts to check for leaks, but I'm pretty sure it's not just a seal. A mechanic pal is going to trade services, so the labor will be cost effective for me. I just need to find a reliable source for parts, even if that means just getting a reman from GM.

I've had more time to scour the net for info on Monster Transmission, which has lots of marketing effort, but no real independent reviews. Definitely giving them a pass.

 

I've been driving with the P1870 for 18 months now!

There is a sticky valve & there is a mod that can be done. I was originally told it's not critical so 18 months later & I'm still good. Will try get the extended warrenty insurance to fix it after the winter.
Fortunately untill now I've done mostly town driving & don't experience the problem.
I only experience the rough gear change when the transmission is very hot like after half an hour riding at 100kph on the motorway.

 

I was told much the same thing, except that my fuel consumption is about 20% worse, which I was also told to expect. That, and the waste of power is noticeable. Do you feel a lot of slipping with yours, kiwiblazer?

 

I think there is, although the Chevy guys seem to think it's ok & the transmission guys who road tested it at the time & said it was still good. Performance & economy has been about the same since I bought the truck, so I really have nothing to compare it with.
In respect of economy, all Blazer owners I've been able to speak to have lousy economy.
Probably about 6 or so. Not many Blazers in New Zealand. LOL

I get around 18 litre per 100km (12/13 US mpg) Highway a bit better.