alfolsee2000

I have 2007 HR, 56,000 miles. Vehicle was purchased at auction with front end damages. Changed fenders, bumper, radiator, etc. Checked tranny oil after running the car a couple days and found high level and coolant mixed with transmission oil. Drained and flushed transmission, changed filter at least 5-6 times untill transmission oil was normal red color. Tramsmission worked fine, smooth shifting for the past 3 months. Yesterday transmission would not shift into 4th gear and engine check light came on. Auto parts store read code to be intermittent engine misfire, probably spark plug or spark plug wire. I plan on changing plugs tomorrow and drain and change transmission filter. (hope this helps).
Could I be looking at blown transmission? Have no unusual odors from transmission and still shifts smoothly but will not shift into 4th gear. approx. 3400 rpm at 62 mph. Seems like it was around 2600 rpm at 70mph.
Any advise/help would be appreciated.
I really really like my HHR and would like to keep it.

IgottaWoody

If the miss and trans prob showed up at the same time concentrate on the miss prob first and watch what happens when its fixed and cleared....the codes probably affect the trans and prevent it from shifting into 4th....this car is unique in that it will change its characteristics to protect itself....worth a try

alfolsee2000

I was thinking along those same lines. I have noticed that if the engine is operating at less than optimal performance, certain systems react to this, A/C does not operate if anything wrong with cooling system. I will change the spark plugs later today when it gets a little cooler (97 degrees now).

ChevyMgr

The coolant in the transmission has done damage that flushing will not fix, especially if you have driven it for more than a few miles.

The miss could be a plug but most likely is a coil or cylinder head issue. Sorry neither of these is good news but it is what it is.

alfolsee2000

Thanks for the feed back. Took the coil packs and plugs off. The plugs showed no wear or discoloration. When compared to the ones the parts store sold me, were not the same, confirmed that plugs that were removed were the right ones, so put the same plugs back, cranked up and ran great, no miss. Cleared the codes and ran it, but still would not shift to 4th gear. I have new trans filter so will change the filter and oil and get the oil level right and see what happens. Would it be better to get the transmission rebuilt or replace this one with a rebuilt trans.

alfolsee2000

Forgot to mention one thing. The engine was run in the shop in park with coolant in the transmission but not driven on the road.

IgottaWoody

Somehow I missed the coolant in the trans part...thats never a good thing and could have caused damage, could have gummed up things..question is HOW did coolant get in there.?
Since 4th is generally OD maybe theres something there thats not right...check the harness plug to the trans, could be knocked loose

alfolsee2000

The coolant got in transmission line at oil cooler inside radiator, replaced radiator and flushed transmission several times till transmission oil and color returned to normal. I will check the plug at the transmission. The thing that has me confused is the fact that all other gears shift smoothly, no noise, no clunking...everything else fine except not going to OD. Will check plug and change tranny oil and filter and post results. thanks

alfolsee2000

Ok, changed the transmission oil and filter with new gasket. The oil did not look or smell unusual. Also checked the electrical plug and wiring, all looks ok.
all fuses are ok. Still no shift to overdrive. Went to local transmission shop to troubleshoot transmission but shop is closed, on vacation. ?????

oneton

I don't know if auto parts can ck trans codes, I would have a dealer or a good trans shop ck it to see if it is hard parts or elect.