hi, I think this is my first post in this forum. I have a 2007 H3 with 170k miles. Recently I noticed that at stop lights the trans seemed to be slipping a little bit. within 2 days of first noticing the problem, the problem got much worse. when the truck is cold, it seems to shift ok, but as soon as it hits operating temp( just above half way on temp gauge) the problems start. I can hear a whining sound which is kind of like what you would expect from a bad accessory bearing. its not really a grinding, but does seem like it could be metal on metal....the sounds gets louder with rpms. when coasting the sound the almost goes away. finally after a couple of days of this, at operating temperature I lost all gears. press on the accelerator and almost no engagement of gears. turning the car off and then back on got me just enough gear back to limp to my local mechanic. I lost gears 4-5 times within 3 miles. I did not think to try manual shifting, I just left it in D. I also checked the trans fluid when the engine was hot and it showed full. I've been trying to research this and sounds like it could be: blown trans pump, TCM, etc. I don't think its electrical, eg TCM because I hear a mechanical problem( the whining./bearing sound). My mechanic hasn't been able to look at the truck yet but I was hoping someone on this forum might have some ideas. thanks

 

Welcome to HF.

Your trans has lived beyond its life expectancy, time for a rebuild. When was the last time you changed the Trans Fluid and Filter?

Fluid level is important, but fluid quality is how you check the health of an auto trans. Dark, burnt smell coffee is BAD!

 

huh, so the 4L60e, one of GM's/Chevy's most common engines from the time, only lasts 170k miles...and thats considered normal?

 

Only 170K miles??????????? They normally only get that far on a heavy full time 4X4 truck if provided regular maintenance. Since you declined to answer my question regarding when the last time the Trans Fluid & Filter were changed, I'm thinking you did pretty well so far.

Cracks me up how many drivers have no idea what happens when the Trans pukes.

Good luck and let us know how it turns out.

 

so a Hummer H3(aka Chevy Colorado ) is a "heavy" truck? and I should be thankful to have gotten 170k miles? I don't know the maintenance history because I bought the truck this past December.
the truck is going to the dealer this week. I hate dealers, but the small town where the truck is at doesn't have an independent who can handle trans work. theories so far are: 1) TCM 2) Torque Converter 3) Trans pump 4) Transfer case.
TCM doesn't explain the mechanic sound I hear when the trans fails. also seems odd that the truck shifts when cold, but not after being warmed up. my theory there is that the viscosity of the trans fluid when cold is enough to enable shifts, but after heating up and viscosity thins out, shifts fail....to me that suggests an issue with the viscous coupling in the torque converter. I should hear from the mechanic next week.

 

An H3 is NOT a Colorado, they share some frame pieces, depending upon the Colly options, they can share the same 3.7L, that is where the comparison ends.

2007 Colly Extended Cab 4X4 w/ 3.7L curb weight 4,062 lbs (not FT 4X4).
2007 H3 curb weight 4700 lbs.

Your 2007 H3 does not have a TCM, those started in 2008+ years. Not the T Case either, those either fail to lock/unlock, or the chain is toast and there is nothing except a lot of racket.
TQ Converter issues are usually in lock-up, either failure or refusal to unlock.
You might be onto something with a possible pump failure, but if you have a Trans with 170K out of the truck, it would be a poor choice not to at lease rebuild the basics with new bands, springs, seals etc. I am confident the dealer is going to gouge the chit out of you with labor rates, then they are going to try to sell you a new replacement Trans. Replace parts is their motto. A good Trans guy is a good guy to befriend.

Does it trigger a code or CEL?

Anyways, best of luck, just like we hope to win the lotto, we can hope your issue is minor.

I look at rebuild time as the opportunity to build a better than stock Trans, like: Beast Sunshell; Sonnax smart tech input housing with Borg Warner 29 element dual cage sprag; Sonnax 2nd & 4th gear super hold servos; new GM reverse input drum and Sonnax extra wide Kevlar band....

 

I haven't been to a dealer in over 15 years for exactly that reason. in this case I had to leave the Hummer 400 miles from home and all I could find was a Chevy dealer in the area that does work on GMC as well. Yes, I am expecting them to tell me that they don't do rebuilds( like most shops these days) and that an OEM Trans is $3500 + 20hrs labor at $150/hr. I've done a ton of work on age truck in the last 6 months and it was driving great until the trans broke. what makes these expensive repairs tough to swallow is the value of the truck can be more than $5-6k according to KBB. its worth more than that to me when it works, but at some point you need to stop repairing and move on

 

I hear you, the situation sucks.

Up here in the D, there are many Transmission Shops capable of not just rebuilds, but performance builds for race applications. They don't call it the Motor City for noting.

My Trans guy is my business partner's cousin, his shop is all of maybe 11 miles away. We trade work and it's all good.

 

You don't need a dealer to drop the 4l60e. Diy or take it to a shop that can R&R. Drive in with a reman or good used transmission in the back, and have them swap it out. Just find a shop that can R&R ,[40.470867299999995,-74.6616433]];tbs:lrf:!1m4!1u3!2m2!3m1!1e1!1m4!1u2!2m2!2m1!1e1! 2m1!1e2!2m1!1e3,lf:1]transmissions!

 

can someone recommend a source for plug & play 4L60E for my H3? dealer service just called. they want to source a Reman trans and quoted me $3100 + labor. they said the real problem is finding a reman trans. when I do a google for trans, they seem to be available from all kinds of places. I just need a low cost trans...so if someone can recommend a source that would be great.