4L60E Hard 1-2 shift

[Max Power]

I bought a beater truck so I can keep my LMM nice and new looking. No more hauling garbage in it and driving down gravel roads.

The truck is a 2003 Sierra with a 4.8L and i assume a 4L60E? It has about 200,000 miles on it. The truck runs good and was fairly well maintained. The trans doesn't seem to slip but it does shift hard from 1 to 2 and also seems to shift at a little higher rpm's then I would expect.

I'm not looking to spend a whole pile of money on this truck because it is a beater however if I need to spend some to save some down the road I am always willing to do a bit of preventative maintenance.

Are these issues common? Can they be fixed with a shift kit or some other reasonably cheap fix or do I need to have it rebuilt?

Thanks in advance.

 

[rgullett83]

I would check codes, might have a 1870 stored, used to be a common problem. there are kits out there to correct the issue, but I usually cut a piece of brake line and put it in the tcc isolator valve, which causes tcc to lock up, and no pwm apply.

 

[Max Power]

I'll check the codes in about 30 mins Thanks.

 

[THEFERMANATOR]

With that many miles a build will probably be in your future. Another thing to watch for is a hard 1-2 shift will normally cause the sunshell to break in a quick fashion. I've seen a bad 1-2 solonoid cause excessively hard shifts before, but it could also be that somebody else has played with it before you and installed a corvette servo and a B valve in the valve body without changing out the spring on it. With that many miles there is no telling what has been done before you got it is the problem.

Mike L will know ALOT more than I do about em, just relaying along a few of the things I've seen do this.

 

[Max Power]

It's not snap your neck hard, just firmer then it should be.

Apparantly the truck has never had the trans touched. It's a one owner and maintained by the same shop.

 

[Jack Bauer]

My 4l60e always shifted hard that tranny is a POS as far as im concerned unless you build it.

I had mine built with the corvette servos and all the other goodies to go along with it. The tranny always was great after that.

I als remeber some kind of ground wire that wasnt installed on the trucks from the factory that went to the pressure control module that really made a difference in how it shifted.

But in reality like above poster said a build is probably in your future.

 

[duratothemax]

4L60 with 200k miles on it? wow!

 

[Max Power]

Well he looks after about 10 trucks so he could be wrong but he told me he thought it had never been touched, and it's not like that's a selling feature.

 

[Max Power]

No codes at all so I suspect they've been cleared recently.

Is there any harm in doing an SK 4L60E shift kit? Worst case scenerio I am out the cost of a shift kit and my time? It looks like this can be done with the trans in the truck?

 

[Mike L.]

Worn 1/2 acumalator bore in the valve body from high mileage. No matter what you do you are on borrowed time.

 

[Max Power]

Mike what should I expdect to pay for a rebuilt? I don't need high hp, it won't pulll, just a shop truck. It's basically in retirement now. I doubt it will get 5-10k per year. If I could patch it and make it semi reliable I would be happy.

So a shift kit is a waste of money at this point? What about a replacement valve body?

 

[Mike L.]

Mike what should I expdect to pay for a rebuilt? I don't need high hp, it won't pulll, just a shop truck. It's basically in retirement now. I doubt it will get 5-10k per year. If I could patch it and make it semi reliable I would be happy.

So a shift kit is a waste of money at this point? What about a replacement valve body?

Try the S/K.

 

[Max Power]

Thanks, I guess I don't have much to lose.

WIll it help it last longer or just make it feel better with no longevity gains?

I'll do it right if I need to do it right. Do you offer rebuilt exchanges or can you recommend anyone who does good work that offers rebuilt exchanges?

 

[THEFERMANATOR]

If you have some basic tools you can build it yourself for not much money provided all of the solonoids in it are good. The last stock build I did with an HD-2 shift kit cost less than $400 for everything except the solonoids(one was bad and the customer wanted all new). The first one I built only took me about a day to teardown and re-assemble. I would say a basic kit with a corvette servo, a TRANSTAR converter, beast sunshell(this should be mandatory I think in any 4L60 build), and an SK kit wouldn't set you back much money 2 days time and you'll be good for another 200K probably.

Drop the pan first and see what it looks like inside. While your there take a screwdriver and check the band for side to side movement. If there is a bunch of black material in the pan then you know there is no sense in going any furthur without a build. If it looks clean then do like Mike said and roll the dice. Maybe also put a SONNAX 1-2 valve kit in the valve body while you're there with a corvette servo. And definately replace the seperator plate. I've yet to tear one down that didn't have at least one check ball seat in the plate hammered out.

 

[Mike L.]

Thanks, I guess I don't have much to lose.

WIll it help it last longer or just make it feel better with no longevity gains?

I'll do it right if I need to do it right. Do you offer rebuilt exchanges or can you recommend anyone who does good work that offers rebuilt exchanges?

Sorry
I offer nothing for the 4L60E because I won't do any tech support for it. Way too much trouble.

 

[dmaxvaz]

4L60 with 200k miles on it? wow!

MY SISTER HAS A SUBURBAN WITH 260K ON THE ORIGINAL TRANS I JUST REPLACED IT A COUPLE MONTHS AGO

 

[Mike L.]

MY SISTER HAS A SUBURBAN WITH 260K ON THE ORIGINAL TRANS I JUST REPLACED IT A COUPLE MONTHS AGO

And I have worked on hundeds of them that never made it to 50K.