BUYER BEWARE...KNOW YOUR REPAIR SHOP. There wasa transmission repaircompany and two of their shops kept a transmission pan full of metal particles and shavings in the back of their shop. They would bring out those fake transmission panstoshow a potential customer in order to convince them that their transmissionneeds to be rebuilt. When the customer agreed, the shop made a minoradjustment to the transmission and charged them $1500 for a complete rebuild. After several complaints, the City Attorney had acertified mechanic mark two transmissions that were in perfect condition and sent the cars to the repair shops. After the sting, the managers of those shops were arrested for fraud and tossed in jail. When the twowere relased on probation, their company paid a $10,000 fine, andthen moved the managers totransmission shops in different areas of town.

 

I have a 2000 Blazer that does exactly what the bulletin says: when the tranny gets hot it starts banging from 1st to 2nd. I can drive it all day around town and it never does it, but get out on the interstate and drive a couple of hundred miles and it does it every time. I'll have to save up some money to have that valve replaced. Now if I could find a definate fix for my bouncing fuel gauge I'd have it made.[8D]

 

I have a similar 1st to 2nd hard shift when the transmission is cold and occasionally when it is at operating temp. There is no bang, grinding, warning lights or codes. The hard shift only happens when I am accelerating and if I back off the gas just before the shift it does not do it. If I’m accelerating really fast it does not do it, and if after that I take it easy on accelerating it will do it. I swear the tranny is learning my driving habits and trying to quick shift until it realizes I’m not trying to, then it starts acting normal.

When driving about 10 – 15mph and going into a corner I let off the gas and break slightly or drift into the corner then when I give it a little gas the transmission takes a second or two and finally engages similar to the 1st to 2nd hard shift. This has always happened as long as I can remember. I not familiar with transmissions or rear differentials so as far as I know this is normal. I don’t think I have a limited slip differential but the term “limited slip” sounds like my problem. I changed my differential fluid about 2000 miles ago so that is covered.

I am due for a tranny service so I want to change the fluid this weekend, but if there is a part I need to replace first I will be upset about wasting my money and having to drain it again to replace a part. Worst case scenario…. If I have to replace a valve body is that something I can do without removing the tranny?

Is there any reason why I should not do the tranny fluid change myself?
Do the tranny shops use some sort of machine to flush the system?

2003 Xtreme (75k miles)
Four-speed auto (Hydra-Matic 4L60-E)

 

Would a p1870 code cause my 4wd not to work?

 

Bought an updated valve body from a gm dealer today and its going to a tranny shop later to swap them out. I'll update everyone when i get my truck back. Hope this fixes it!

 

Would love to know your thoughts on this (and the results )

I've got the problem as described--over 200* I get a hard 1-2 shift. Fortunately for me it's always been on the way home, so I only have 2-3 shifts needed before I can park it. Since last summer the ATF typically never exceeds 180* according to the scangauge, so this has only happened maybe 2-3X total as well.

I've been debating taking it in as the problem is intermittent and there are no codes set. But I know once summer rolls around I'll be seeing 200*+ temps on a regular basis.

Also bought a cooler I plan to install soon--figure hey maybe I can just keep the ATF before 200

 

So its been about 2 weeks since I had the valve swapped with one from the GM dealer and it fixed the problem. No more hard 1-2 shifts! I went the more expensive route (roughly $300 for the part and $250 for labor) by buying a remanned valve body from a GM dealer, but talking to the transmission shop guy, reaming the and replacing the TCC solenoid gives you same result just alot cheaper. The codes only set in when the hard shifts happen twice on consecutive trips. Thats why you're not getting the check engine light. The added cooler is a great idea and should keep the temp below 193*. I'm not quite sure if this will fix the problem but it should at least prevent it.