CK5
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No power driving up hill
- Thread starter Blazer Ralph
- Start date
Good point!
I went out towards pinecrest from San Jose, it drove great until I got to the hills, then she was crawling, like 15 mph maybe and wouldn’t go faster! No smoke or anything just crawling. When I got to my hunting spot I was able to use 4x4 and truck did great! I just checked tire size this morning and they are actually 35” tires
I just ordered new tires 28.9” diameter, guess I’ll start there and see. I’ll keep you all updated
Timing was set correctly at the mechanic shop
@Blazer Ralph i think you overshot with 29” tires. Factory was 31x10.50. It may look little weird with 29” tires. Was the truck lifted to fit the 34” tires?
Oh I’m gonna add some doubt here
“Mechanic” probably sent it to what they want to see for the emissions based on the sticker on the radiator. In actuality, these trucks run better. If you set the timing based off of how it runs, not according to what GM tells you to do.
And +1 to 31/10.5s
28.9 is thr true diameter ? That might be a 30 " tire advertised.
Normally a 35" tire needs @3" of lift closer to 4".
Pinecrest is in the west Sierra's, haven't spent much time on that side, still steep grades.
At 15mph you should have been in 1st gear climbing the hills, that is really to slow, I complain when I get slowed down to the 35 mph range.
This mechanic shop you're using tell us about them. What do they know about old cars?
If your truck still has a gm Quardrajet I encourage you to stay with that.
Normally a 35" tire needs @3" of lift closer to 4".
Pinecrest is in the west Sierra's, haven't spent much time on that side, still steep grades.
At 15mph you should have been in 1st gear climbing the hills, that is really to slow, I complain when I get slowed down to the 35 mph range.
This mechanic shop you're using tell us about them. What do they know about old cars?
If your truck still has a gm Quardrajet I encourage you to stay with that.
rampage
3/4 ton status
It would be a lot cheaper to find a used axle with the correct gears. But did you even check the gear ratio before ordering tires or are you just gonna blindly throw parts at it?
It was lifted, I looked online at multiple sights for wheel size and they all come up as 29” tires
Yes still has quadrajet
I ordered good year wrangler trail runner A/T tires 235/75R15, I will stay with the quadrajet
A 1982 K5/K10 came with P215/75R15’s and the 31’s was optional.
As others have said up above by all means verify your current gear ratio first.
And no doubt a 29” tall tire is not going to look good with a lift or not - also the ground clearance sucks.
A common 31” tall tire will look much better and won’t hurt the gear loss effect so much that you’ll feel it - it’s small enough.
Verify things like already mentioned such as proper timing and not super emission retarded setting which will make a motor WEAK along with your carb adjustments and fuel delivery - it’s possible your fuel pump is weak and while under load it can’t supply enough fuel.
As others have said up above by all means verify your current gear ratio first.
And no doubt a 29” tall tire is not going to look good with a lift or not - also the ground clearance sucks.
A common 31” tall tire will look much better and won’t hurt the gear loss effect so much that you’ll feel it - it’s small enough.
Verify things like already mentioned such as proper timing and not super emission retarded setting which will make a motor WEAK along with your carb adjustments and fuel delivery - it’s possible your fuel pump is weak and while under load it can’t supply enough fuel.
Awesome thanks for info, I cancelled tire order so I can get correct size, I will check timing and get carb tuned right thank you
So do you know for sure which transmission it is? Do you have a picture of the pan? If you count the detents in the shift lever, is it PRND21 or PRND321?
Because having OD changes what the ideal setup is for gears/tires. Either way the correct answer is:
Because having OD changes what the ideal setup is for gears/tires. Either way the correct answer is:
- Go figure out what gear ratio you have
- Go figure out which transmission you have
- Form a tire plan (i.e. keep the 35's or go down to 33's, depending on lift)
- Choose the ideal ratio for that tire and transmission (i.e. 4.56 or 4.88 with 35's and OD)
- Start spending money
Blue85’s gotta good point - get a pick of the gear indicator above the steering wheel column and bottom center of the instrument panel and crawl under it and take a few pics of the transmission pan and we can identify it for you so you will know for certain what you’re working with.
Also, if the RPO code sticker is still in the glove box door include that and we might be able to identify what gear ratio you got.
Also, if the RPO code sticker is still in the glove box door include that and we might be able to identify what gear ratio you got.
Ok, when I get home I will get some pics, thank you guys for all your help! You all are awesome! I really appreciate it
Ok so it’s definitely a th350 transmission, I can add pics without upgrading this forum. But I checked the shape of the pan. There are no tags in glove box
thats to bad about the rpo sticker is lost info when thats gone.
